chơi xổ số keno trực tuyến

{"appState":{"pageLoadApiCallsStatus":true},"categoryState":{"relatedCategories":{"headers":{"timestamp":"2025-01-31T04:01:09+00:00"},"categoryId":33758,"data":{"title":"Astronomy","slug":"astronomy","image":{"src":null,"width":0,"height":0},"breadcrumbs":[{"name":"Academics & The Arts","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"},"slug":"science","categoryId":33756},{"name":"Astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"},"slug":"astronomy","categoryId":33758}],"parentCategory":{"categoryId":33756,"title":"Science","slug":"science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"}},"childCategories":[],"description":"Get to know the stars. Plus: gravity, solar activity, lunar geology, and more.","relatedArticles":{"self":"//dummies-api.coursofppt.com/v2/articles?category=33758&offset=0&size=5"},"hasArticle":true,"hasBook":true,"articleCount":65,"bookCount":2},"_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"relatedCategoriesLoadedStatus":"success"},"listState":{"list":{"count":10,"total":65,"items":[{"headers":{"creationTime":"2017-03-26T17:11:44+00:00","modifiedTime":"2024-10-19T19:31:32+00:00","timestamp":"2024-10-19T21:01:03+00:00"},"data":{"breadcrumbs":[{"name":"Academics & The Arts","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"},"slug":"science","categoryId":33756},{"name":"Astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"},"slug":"astronomy","categoryId":33758}],"title":"Important Events of the Space Age","strippedTitle":"important events of the space age","slug":"the-space-age","canonicalUrl":"","百度搜引索擎简化":{"metaDescription":"The Soviet Union's successful launch of the first satellite, Sputnik, marks the start of the Space Age. Here are many other significant events.","noIndex":0,"noFollow":0},"content":"The Space Age, generally considered started by the launch of the Russian satellite Sputnik, is defined by the events surrounding space exploration and development of space technology. This list maps out major events of the Space Age:\r\n\r\n<b>1957</b> The Soviet Union launches Sputnik 1, the first artificial satellite to orbit Earth.\r\n\r\n<b>1958</b> Using the satellite Explorer 1, James Van Allen discovers Earth’s radiation belts (<i>magnetosphere</i>).\r\n\r\n<b>1960</b> Frank Drake begins the Search for Extraterrestrial Intelligence (SETI) at the National Radio Astronomy Observatory in Green Bank, West Virginia.\r\n\r\n<b>1961</b> Yuri Gagarin makes the first manned space flight.\r\n\r\n<b>1963</b> Valentina Tereshkova is the first woman in space.\r\n\r\n<b>1967</b> Jocelyn Bell Burnell and Anthony Hewish discover pulsars.\r\n\r\n<b>1969</b> Neil Armstrong and Buzz Aldrin walk on the moon.\r\n\r\n<strong>1971</strong>: The Soviet Union launches the first space station, Salyut 1.\r\n\r\n<strong>1972</strong>: The Soviet Union's Mars 3 spacecraft makes first soft landing on another planet, Mars.\r\n\r\n<b>1979</b> Using pictures from Voyager 1, Linda Morabito discovers erupting volcanoes on Jupiter’s moon, Io.\r\n\r\n<strong>1981</strong>: NASA's Columbia shuttle becomes first winged spaceship to orbit Earth and return to airport landing.\r\n\r\n<b>1987 </b>Ian Shelton discovers the first supernova since 1604 plainly visible to the naked eye.\r\n\r\n<b>1990</b> The Hubble Space Telescope launches.\r\n\r\n<b>1991</b> Alexander Wolszczan discovers planets orbiting a pulsar — the first known planets outside the solar system.\r\n\r\n<b>1995</b> Michel Mayor and Didier Queloz discover 51 Pegasi B, the first planet of a normal star beyond the Sun.\r\n\r\n<b>1998</b> Two astronomer teams discover that the expansion of the universe is getting faster, perhaps due to a mysterious “dark energy” associated with the vacuum of space.\r\n\r\n<b>1999</b> Mars Global Surveyor finds that Mars may have had an ocean at one time.\r\n\r\n<b>2003 </b>The<b> </b>Wilkinson Microwave Anisotropy Probe satellite finds that the universe is 13.7 billion years old.\r\n\r\n<b>2012</b> The Kepler spacecraft finds that there probably are billions of planets in orbit around stars in our galaxy, and the rover Curiosity lands on Mars.\r\n\r\n<strong>2015 </strong>The New Horizons probe explores Pluto and its moons and then heads outward in the Kuiper Belt.","description":"The Space Age, generally considered started by the launch of the Russian satellite Sputnik, is defined by the events surrounding space exploration and development of space technology. This list maps out major events of the Space Age:\r\n\r\n<b>1957</b> The Soviet Union launches Sputnik 1, the first artificial satellite to orbit Earth.\r\n\r\n<b>1958</b> Using the satellite Explorer 1, James Van Allen discovers Earth’s radiation belts (<i>magnetosphere</i>).\r\n\r\n<b>1960</b> Frank Drake begins the Search for Extraterrestrial Intelligence (SETI) at the National Radio Astronomy Observatory in Green Bank, West Virginia.\r\n\r\n<b>1961</b> Yuri Gagarin makes the first manned space flight.\r\n\r\n<b>1963</b> Valentina Tereshkova is the first woman in space.\r\n\r\n<b>1967</b> Jocelyn Bell Burnell and Anthony Hewish discover pulsars.\r\n\r\n<b>1969</b> Neil Armstrong and Buzz Aldrin walk on the moon.\r\n\r\n<strong>1971</strong>: The Soviet Union launches the first space station, Salyut 1.\r\n\r\n<strong>1972</strong>: The Soviet Union's Mars 3 spacecraft makes first soft landing on another planet, Mars.\r\n\r\n<b>1979</b> Using pictures from Voyager 1, Linda Morabito discovers erupting volcanoes on Jupiter’s moon, Io.\r\n\r\n<strong>1981</strong>: NASA's Columbia shuttle becomes first winged spaceship to orbit Earth and return to airport landing.\r\n\r\n<b>1987 </b>Ian Shelton discovers the first supernova since 1604 plainly visible to the naked eye.\r\n\r\n<b>1990</b> The Hubble Space Telescope launches.\r\n\r\n<b>1991</b> Alexander Wolszczan discovers planets orbiting a pulsar — the first known planets outside the solar system.\r\n\r\n<b>1995</b> Michel Mayor and Didier Queloz discover 51 Pegasi B, the first planet of a normal star beyond the Sun.\r\n\r\n<b>1998</b> Two astronomer teams discover that the expansion of the universe is getting faster, perhaps due to a mysterious “dark energy” associated with the vacuum of space.\r\n\r\n<b>1999</b> Mars Global Surveyor finds that Mars may have had an ocean at one time.\r\n\r\n<b>2003 </b>The<b> </b>Wilkinson Microwave Anisotropy Probe satellite finds that the universe is 13.7 billion years old.\r\n\r\n<b>2012</b> The Kepler spacecraft finds that there probably are billions of planets in orbit around stars in our galaxy, and the rover Curiosity lands on Mars.\r\n\r\n<strong>2015 </strong>The New Horizons probe explores Pluto and its moons and then heads outward in the Kuiper Belt.","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}}],"primaryCategoryTaxonomy":{"categoryId":33758,"title":"Astronomy","slug":"astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"secondaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"tertiaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"trendingArticles":null,"inThisArticle":[],"relatedArticles":{"fromBook":[{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246756,"title":"How To Watch Meteor Showers","slug":"viewing-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246756"}},{"articleId":246753,"title":"Spotting Sporadic Meteors, Fireballs, and Bolides","slug":"spotting-sporadic-meteors-fireballs-bolides","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246753"}}],"fromCategory":[{"articleId":300371,"title":"The Autumnal Equinox Marks Our Seasonal Transition","slug":"the-autumnal-equinox-marks-the-transition-to-fall","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/300371"}},{"articleId":292167,"title":"The Magic of the Moon and the Total Lunar Eclipse","slug":"dont-miss-out-on-this-months-lunar-eclipse","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/292167"}},{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}}]},"hasRelatedBookFromSearch":false,"relatedBook":{"bookId":281963,"slug":"astronomy-for-dummies","isbn":"9781394163076","categoryList":["academics-the-arts","science","astronomy"],"amazon":{"default":"//www.amazon.com/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","ca":"//www.amazon.ca/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","indigo_ca":"//www.tkqlhce.com/click-9208661-13710633?url=//www.chapters.indigo.ca/en-ca/books/product/139416307X-item.html&cjsku=978111945484","gb":"//www.amazon.co.uk/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","de":"//www.amazon.de/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20"},"image":{"src":"//coursofppt.com/wp-content/uploads/astronomy-for-dummies-5th-edition-cover-9781394163076-202x255.jpg","width":202,"height":255},"title":"Astronomy For Dummies","testBankPinActivationLink":"//testbanks.wiley.com","bookOutOfPrint":true,"authorsInfo":"<p><p><b><b data-author-id=\"9879\">Stephen P. Maran</b>, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects.</p>","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. 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Historically, astronomers described comets as having a head and tail or tails, but with additional research, they've been able to clarify the nature of a comet's structure.\r\n\r\n[caption id=\"attachment_246765\" align=\"alignnone\" width=\"535\"]<img class=\"size-full wp-image-246765\" src=\"//coursofppt.com/wp-content/uploads/astronomy-comet.jpg\" alt=\"astronomy-comet\" width=\"535\" height=\"256\" /> A comet is really just a dirty ice ball.[/caption]\r\n<h2 id=\"tab1\" >The nucleus</h2>\r\nAstronomers initially named a bright point of light in the head of a comet the <em>nucleus.</em> Today we know that the nucleus is the true comet — the so-called dirty ice ball. The other features of a comet are just emanations that stem from the nucleus.\r\n\r\nA comet far from the Sun is only the nucleus; it has no head or tail. The ice ball may be dozens of miles in diameter or just a mile or two. That size is pretty small by astronomical standards, and because the nucleus shines only by the reflected light of the Sun, a distant comet is faint and hard to find.\r\n\r\nImages of Halley's nucleus from a European Space Agency probe that passed very close to it in 1986 show that the lumpy, spinning ice ball has a dark crust, like the tartufo dessert (balls of vanilla ice cream coated with chocolate) served in fancy restaurants. Comets aren't so tasty, but they <em>are</em> real treats to the eye.\r\n\r\nHere and there on Halley's nucleus, the probe photographed plumes of gas and dust from geyserlike vents or holes, spraying into space from areas where the Sun was warming the surface. Some crust! And in 2004, NASA's Stardust probe got close-up images of the nucleus of Comet Wild-2. This nucleus seems to bear impact craters and is marked with what may be pinnacles made of ice. Those are the cold facts.\r\n\r\nNot all comet nuclei are shaped like Halley's, though. In August 2014, the Rosetta spacecraft reached Comet 67P/Churyumov–Gerasimenko, known as 67P to its friends (like me). Rosetta orbited the comet nucleus while the comet orbited the Sun until the end of the European Space Agency mission in September 2016. Its photographs revealed a nucleus shaped roughly like a dumbbell with two unequal weights. Astronomers referred to the \"weights\" as two <em>lobes</em> of the comet connected by a thinner structure they named the <em>neck</em>. Some astronomers stuck their necks out by theorizing that the odd-shaped nucleus was formed by the low-speed collision of two earlier objects.\r\n<h2 id=\"tab2\" >The coma</h2>\r\nAs a comet gets closer to the Sun, solar heat vaporizes more of the frozen gas, and it spews out into space, blowing some dust out, too. The gas and dust form a hazy, shining cloud around the nucleus called the <em>coma</em> (a term derived from the Latin for \"hair,\" not the common word for an unconscious state). Almost everyone confuses the coma with the head of the comet, but the head, properly speaking, consists of both the coma and the nucleus.\r\n\r\nThe glow from a comet's coma is partly the light of the Sun, reflected from millions of tiny dust particles, and partly emissions of faint light from atoms and molecules in the coma.\r\n<h2 id=\"tab3\" >A tale of two tails</h2>\r\nThe dust and gas in a comet's coma are subject to disturbing forces that can give rise to a comet's tail(s): the dust tail and the plasma tail. (Sometimes when you view a comet, you see just one kind of tail, but when you're lucky, you see both.)\r\n\r\nThe pressure of sunlight pushes the dust particles in a direction opposite the Sun, producing the comet's <em>dust tail.</em> The dust tail shines by the reflected light of the Sun and has these characteristics:\r\n<ul>\r\n \t<li>A smooth, sometimes gently curved appearance</li>\r\n \t<li>A pale yellow color</li>\r\n</ul>\r\n[caption id=\"attachment_246766\" align=\"alignnone\" width=\"351\"]<img class=\"size-full wp-image-246766\" src=\"//coursofppt.com/wp-content/uploads/astronomy-sun.jpg\" alt=\"astronomy-sun\" width=\"351\" height=\"400\" /> A comet's tail points away from the Sun.[/caption]\r\n\r\nThe other type of comet tail is a <em>plasma tail</em> (also called an ion tail or a gas tail). Some of the gas in the coma becomes <em>ionized,</em> or electrically charged, when struck by ultraviolet light from the Sun. In that state, the gases are subject to the pressure of the <em>solar wind,</em> an invisible stream of electrons and protons that pours outward into space from the Sun.\r\n\r\nThe solar wind pushes the electrified cometary gas out in a direction roughly opposite of the Sun, forming the comet's plasma tail. The plasma tail is like a wind sock at an airport: It shows astronomers who view the comet from a distance which way the solar wind is blowing at the comet's point in space.\r\n\r\nIn contrast to the dust tail, a comet's plasma tail has the following:\r\n<ul>\r\n \t<li>A stringy, sometimes twisted, or even broken appearance</li>\r\n \t<li>A blue color</li>\r\n</ul>\r\nNow and then, a length of plasma tail breaks from the comet and flies off into space. The comet then forms a new plasma tail, much like a lizard that grows a new tail when it loses its first one. The tails of a comet can be millions to hundreds of millions of miles long.\r\n\r\nWhen a comet heads inward toward the Sun, its tail or tails stream behind it. When the comet rounds the Sun and heads back toward the outer solar system, the tail still points away from the Sun, so the comet now follows its tail. The comet behaves to the Sun as an old-time courtier did to his emperor: never turning his back on his master. The comet shown could be going clockwise or counterclockwise, but either way, the tail always points away from the Sun.\r\n\r\nThe coma and tails of a comet are just a vanishing act. The gas and dust shed by the nucleus to form the coma and tails are lost to the comet forever — they just blow away. By the time the comet travels far beyond the orbit of Jupiter, where most comets come from, it consists of only a bare nucleus again. And the nucleus is a little smaller, due to the gas and dust that it sheds. The dust the comet loses may someday produce a meteor shower, if it crosses Earth's orbit.\r\n\r\nHalley's comet is a good example of the wasting-away process. Halley's nucleus decreases by at least a meter (39.37 inches, or slightly more than a yard) every 75 to 77 years when it passes near the Sun. The nucleus is only about 10 kilometers (10,000 meters or 6.2 miles) in diameter right now, so Halley's comet will survive only about 1,000 more orbits, or about 75,000 years. Dust shed by the famous comet causes two of the top annual meteor showers, the Eta Aquarids and the Orionids.","description":"A comet is a stuck-together mixture of ice, frozen gases (such as the ices of carbon monoxide and carbon dioxide), and solid particles — the dust or \"dirt\" shown here. Historically, astronomers described comets as having a head and tail or tails, but with additional research, they've been able to clarify the nature of a comet's structure.\r\n\r\n[caption id=\"attachment_246765\" align=\"alignnone\" width=\"535\"]<img class=\"size-full wp-image-246765\" src=\"//coursofppt.com/wp-content/uploads/astronomy-comet.jpg\" alt=\"astronomy-comet\" width=\"535\" height=\"256\" /> A comet is really just a dirty ice ball.[/caption]\r\n<h2 id=\"tab1\" >The nucleus</h2>\r\nAstronomers initially named a bright point of light in the head of a comet the <em>nucleus.</em> Today we know that the nucleus is the true comet — the so-called dirty ice ball. The other features of a comet are just emanations that stem from the nucleus.\r\n\r\nA comet far from the Sun is only the nucleus; it has no head or tail. The ice ball may be dozens of miles in diameter or just a mile or two. That size is pretty small by astronomical standards, and because the nucleus shines only by the reflected light of the Sun, a distant comet is faint and hard to find.\r\n\r\nImages of Halley's nucleus from a European Space Agency probe that passed very close to it in 1986 show that the lumpy, spinning ice ball has a dark crust, like the tartufo dessert (balls of vanilla ice cream coated with chocolate) served in fancy restaurants. Comets aren't so tasty, but they <em>are</em> real treats to the eye.\r\n\r\nHere and there on Halley's nucleus, the probe photographed plumes of gas and dust from geyserlike vents or holes, spraying into space from areas where the Sun was warming the surface. Some crust! And in 2004, NASA's Stardust probe got close-up images of the nucleus of Comet Wild-2. This nucleus seems to bear impact craters and is marked with what may be pinnacles made of ice. Those are the cold facts.\r\n\r\nNot all comet nuclei are shaped like Halley's, though. In August 2014, the Rosetta spacecraft reached Comet 67P/Churyumov–Gerasimenko, known as 67P to its friends (like me). Rosetta orbited the comet nucleus while the comet orbited the Sun until the end of the European Space Agency mission in September 2016. Its photographs revealed a nucleus shaped roughly like a dumbbell with two unequal weights. Astronomers referred to the \"weights\" as two <em>lobes</em> of the comet connected by a thinner structure they named the <em>neck</em>. Some astronomers stuck their necks out by theorizing that the odd-shaped nucleus was formed by the low-speed collision of two earlier objects.\r\n<h2 id=\"tab2\" >The coma</h2>\r\nAs a comet gets closer to the Sun, solar heat vaporizes more of the frozen gas, and it spews out into space, blowing some dust out, too. The gas and dust form a hazy, shining cloud around the nucleus called the <em>coma</em> (a term derived from the Latin for \"hair,\" not the common word for an unconscious state). Almost everyone confuses the coma with the head of the comet, but the head, properly speaking, consists of both the coma and the nucleus.\r\n\r\nThe glow from a comet's coma is partly the light of the Sun, reflected from millions of tiny dust particles, and partly emissions of faint light from atoms and molecules in the coma.\r\n<h2 id=\"tab3\" >A tale of two tails</h2>\r\nThe dust and gas in a comet's coma are subject to disturbing forces that can give rise to a comet's tail(s): the dust tail and the plasma tail. (Sometimes when you view a comet, you see just one kind of tail, but when you're lucky, you see both.)\r\n\r\nThe pressure of sunlight pushes the dust particles in a direction opposite the Sun, producing the comet's <em>dust tail.</em> The dust tail shines by the reflected light of the Sun and has these characteristics:\r\n<ul>\r\n \t<li>A smooth, sometimes gently curved appearance</li>\r\n \t<li>A pale yellow color</li>\r\n</ul>\r\n[caption id=\"attachment_246766\" align=\"alignnone\" width=\"351\"]<img class=\"size-full wp-image-246766\" src=\"//coursofppt.com/wp-content/uploads/astronomy-sun.jpg\" alt=\"astronomy-sun\" width=\"351\" height=\"400\" /> A comet's tail points away from the Sun.[/caption]\r\n\r\nThe other type of comet tail is a <em>plasma tail</em> (also called an ion tail or a gas tail). Some of the gas in the coma becomes <em>ionized,</em> or electrically charged, when struck by ultraviolet light from the Sun. In that state, the gases are subject to the pressure of the <em>solar wind,</em> an invisible stream of electrons and protons that pours outward into space from the Sun.\r\n\r\nThe solar wind pushes the electrified cometary gas out in a direction roughly opposite of the Sun, forming the comet's plasma tail. The plasma tail is like a wind sock at an airport: It shows astronomers who view the comet from a distance which way the solar wind is blowing at the comet's point in space.\r\n\r\nIn contrast to the dust tail, a comet's plasma tail has the following:\r\n<ul>\r\n \t<li>A stringy, sometimes twisted, or even broken appearance</li>\r\n \t<li>A blue color</li>\r\n</ul>\r\nNow and then, a length of plasma tail breaks from the comet and flies off into space. The comet then forms a new plasma tail, much like a lizard that grows a new tail when it loses its first one. The tails of a comet can be millions to hundreds of millions of miles long.\r\n\r\nWhen a comet heads inward toward the Sun, its tail or tails stream behind it. When the comet rounds the Sun and heads back toward the outer solar system, the tail still points away from the Sun, so the comet now follows its tail. The comet behaves to the Sun as an old-time courtier did to his emperor: never turning his back on his master. The comet shown could be going clockwise or counterclockwise, but either way, the tail always points away from the Sun.\r\n\r\nThe coma and tails of a comet are just a vanishing act. The gas and dust shed by the nucleus to form the coma and tails are lost to the comet forever — they just blow away. By the time the comet travels far beyond the orbit of Jupiter, where most comets come from, it consists of only a bare nucleus again. And the nucleus is a little smaller, due to the gas and dust that it sheds. The dust the comet loses may someday produce a meteor shower, if it crosses Earth's orbit.\r\n\r\nHalley's comet is a good example of the wasting-away process. Halley's nucleus decreases by at least a meter (39.37 inches, or slightly more than a yard) every 75 to 77 years when it passes near the Sun. The nucleus is only about 10 kilometers (10,000 meters or 6.2 miles) in diameter right now, so Halley's comet will survive only about 1,000 more orbits, or about 75,000 years. Dust shed by the famous comet causes two of the top annual meteor showers, the Eta Aquarids and the Orionids.","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}}],"primaryCategoryTaxonomy":{"categoryId":33758,"title":"Astronomy","slug":"astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"secondaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"tertiaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"trendingArticles":null,"inThisArticle":[{"label":"The nucleus","target":"#tab1"},{"label":"The coma","target":"#tab2"},{"label":"A tale of two tails","target":"#tab3"}],"relatedArticles":{"fromBook":[{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246756,"title":"How To Watch Meteor Showers","slug":"viewing-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246756"}},{"articleId":246753,"title":"Spotting Sporadic Meteors, Fireballs, and Bolides","slug":"spotting-sporadic-meteors-fireballs-bolides","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246753"}},{"articleId":246750,"title":"Planning Your First Steps into Astronomy","slug":"planning-first-steps-astronomy","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246750"}}],"fromCategory":[{"articleId":300371,"title":"The Autumnal Equinox Marks Our Seasonal Transition","slug":"the-autumnal-equinox-marks-the-transition-to-fall","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/300371"}},{"articleId":292167,"title":"The Magic of the Moon and the Total Lunar Eclipse","slug":"dont-miss-out-on-this-months-lunar-eclipse","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/292167"}},{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246756,"title":"How To Watch Meteor Showers","slug":"viewing-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246756"}}]},"hasRelatedBookFromSearch":false,"relatedBook":{"bookId":281963,"slug":"astronomy-for-dummies","isbn":"9781394163076","categoryList":["academics-the-arts","science","astronomy"],"amazon":{"default":"//www.amazon.com/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","ca":"//www.amazon.ca/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","indigo_ca":"//www.tkqlhce.com/click-9208661-13710633?url=//www.chapters.indigo.ca/en-ca/books/product/139416307X-item.html&cjsku=978111945484","gb":"//www.amazon.co.uk/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","de":"//www.amazon.de/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20"},"image":{"src":"//coursofppt.com/wp-content/uploads/astronomy-for-dummies-5th-edition-cover-9781394163076-202x255.jpg","width":202,"height":255},"title":"Astronomy For Dummies","testBankPinActivationLink":"//testbanks.wiley.com","bookOutOfPrint":true,"authorsInfo":"<p><p><b><b data-author-id=\"9879\">Stephen P. Maran</b>, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects.</p>","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35300"}},{"authorId":35295,"name":"Richard Tresch Fienberg","slug":"richard-tresch-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35295"}}],"_links":{"self":"//dummies-api.coursofppt.com/v2/books/"}},"collections":[],"articleAds":{"footerAd":"<div class=\"du-ad-region row\" id=\"article_page_adhesion_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_adhesion_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-6531990ee1db0\"></div></div>","rightAd":"<div class=\"du-ad-region row\" id=\"article_page_right_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_right_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-6531990ee22cd\"></div></div>"},"articleType":{"articleType":"Articles","articleList":null,"content":null,"videoInfo":{"videoId":null,"name":null,"accountId":null,"playerId":null,"thumbnailUrl":null,"description":null,"uploadDate":null}},"sponsorship":{"sponsorshipPage":false,"backgroundImage":{"src":null,"width":0,"height":0},"brandingLine":"","brandingLink":"","brandingLogo":{"src":null,"width":0,"height":0},"sponsorAd":"","sponsorEbookTitle":"","sponsorEbookLink":"","sponsorEbookImage":{"src":null,"width":0,"height":0}},"primaryLearningPath":"Explore","lifeExpectancy":"Two years","lifeExpectancySetFrom":"2024-10-19T00:00:00+00:00","dummiesForKids":"no","sponsoredContent":"no","adInfo":"","adPairKey":[]},"status":"publish","visibility":"public","articleId":246764},{"headers":{"creationTime":"2018-11-14T07:43:57+00:00","modifiedTime":"2024-10-19T19:08:24+00:00","timestamp":"2024-10-19T21:01:02+00:00"},"data":{"breadcrumbs":[{"name":"Academics & The Arts","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"},"slug":"science","categoryId":33756},{"name":"Astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"},"slug":"astronomy","categoryId":33758}],"title":"Planning Your First Steps into Astronomy","strippedTitle":"planning your first steps into astronomy","slug":"planning-first-steps-astronomy","canonicalUrl":"","百度搜引索擎简化":{"metaDescription":"Here's some solid advice on how to get started in observing the night sky, including beginner equipment and astronomy clubs.","noIndex":0,"noFollow":0},"content":"If you're just starting to become interested in astronomy, get into the astronomy hobby gradually, investing as little money as possible until you're sure about what you want to do. Here's a plan for acquiring both basic skills and the needed equipment:\r\n<ol>\r\n \t<li>\r\n<p class=\"first-para\"><strong>If you have a late-model computer, invest in a free or inexpensive planetarium program. </strong>Better yet, if you have a smartphone, download and use a free or cheap planetarium app. Start making naked-eye observations at dusk on clear nights and before dawn, if you're an early riser.</p>\r\n<p class=\"child-para\">To plan your observations of planets and constellations, you can also rely on the weekly sky scenes at the <em><a href=\"//www.skyandtelescope.com/\" target=\"_blank\" rel=\"noopener\">Sky & Telescope website</a></em>. If you don't have a suitable computer, plan your observations based on the monthly sky highlights in <em>Astronomy</em> or <em>Sky & Telescope</em> magazine.</p>\r\n</li>\r\n \t<li><strong>After a month or two of familiarizing yourself with the sky and discovering how much you enjoy it, invest in a serviceable pair of 7x50 binoculars.</strong></li>\r\n \t<li>\r\n<p class=\"first-para\"><strong>As you continue to observe the bright stars and constellations, invest in a star atlas that shows many of the dimmer stars, as well as star clusters and nebulae.</strong> Sky & Telescope's Pocket Sky Atlas by Roger W. Sinnott (Sky Publishing, 2007) is a good choice. For maps that are equally good but larger, consult the <em>Jumbo Pocket Sky Atlas</em> by the same author and publisher (2016); you'll just need a bigger pocket.</p>\r\n<p class=\"child-para\">Compare scenes in your star atlas with the constellations that you're observing; the atlas shows their RAs and Decs. Eventually, you'll start to develop a good feel for the coordinate system.</p>\r\n</li>\r\n \t<li><strong>Join an astronomy club in your area, if at all possible, and get to know the folks who have experience with telescopes.</strong></li>\r\n \t<li><strong>If all goes well and you want to continue in astronomy invest in a well-made, high-quality telescope in the 2.5-to-4-inch size range.\r\n</strong>\r\nStudy the telescope manufacturer websites earlier in this chapter or send for catalogs advertised in astronomy magazines. Better yet, talk to experienced astronomy club members if you can. They can advise you on buying a new telescope, and they may know someone who wants to sell a used telescope.</li>\r\n</ol>\r\nYou may be able to borrow a starter telescope and try it out at home. Thanks to the New Hampshire Astronomical Society (NHAS), a movement to place such telescopes in public libraries has begun.\r\n\r\nAstronomy clubs purchase the telescopes; club members modify them for use by inexperienced borrowers and then donate them to the libraries. The telescope model adopted for this project is the Orion StarBlast 4.5, which retails for about $210. It's meant for use on a tabletop but may work for you when just placed on the ground.\r\n\r\nAccording to <em>Sky & Telescope</em>, by late 2016, NHAS had placed more than 100 of these telescopes in New Hampshire libraries, and the St. Louis Astronomical Society had placed over 130 in Missouri and Illinois libraries. Astronomy clubs in other areas are beginning to sponsor library telescopes; search the web to see whether a library telescope program exists near you. Who knows; you may have a (star) blast!\r\n\r\nIf you find that you enjoy astronomy, after a few years, consider moving up to a 6- or 8-inch telescope. It may be harder to use, but you'll be ready to master it after you have some experience. Equipped with a larger telescope, you can see many more stars and other objects.\r\n\r\nYou can get ideas about what larger telescopes to consider by talking to other amateur astronomers and by attending a star party, where you can see many different telescopes in operation and on display.","description":"If you're just starting to become interested in astronomy, get into the astronomy hobby gradually, investing as little money as possible until you're sure about what you want to do. Here's a plan for acquiring both basic skills and the needed equipment:\r\n<ol>\r\n \t<li>\r\n<p class=\"first-para\"><strong>If you have a late-model computer, invest in a free or inexpensive planetarium program. </strong>Better yet, if you have a smartphone, download and use a free or cheap planetarium app. Start making naked-eye observations at dusk on clear nights and before dawn, if you're an early riser.</p>\r\n<p class=\"child-para\">To plan your observations of planets and constellations, you can also rely on the weekly sky scenes at the <em><a href=\"//www.skyandtelescope.com/\" target=\"_blank\" rel=\"noopener\">Sky & Telescope website</a></em>. If you don't have a suitable computer, plan your observations based on the monthly sky highlights in <em>Astronomy</em> or <em>Sky & Telescope</em> magazine.</p>\r\n</li>\r\n \t<li><strong>After a month or two of familiarizing yourself with the sky and discovering how much you enjoy it, invest in a serviceable pair of 7x50 binoculars.</strong></li>\r\n \t<li>\r\n<p class=\"first-para\"><strong>As you continue to observe the bright stars and constellations, invest in a star atlas that shows many of the dimmer stars, as well as star clusters and nebulae.</strong> Sky & Telescope's Pocket Sky Atlas by Roger W. Sinnott (Sky Publishing, 2007) is a good choice. For maps that are equally good but larger, consult the <em>Jumbo Pocket Sky Atlas</em> by the same author and publisher (2016); you'll just need a bigger pocket.</p>\r\n<p class=\"child-para\">Compare scenes in your star atlas with the constellations that you're observing; the atlas shows their RAs and Decs. Eventually, you'll start to develop a good feel for the coordinate system.</p>\r\n</li>\r\n \t<li><strong>Join an astronomy club in your area, if at all possible, and get to know the folks who have experience with telescopes.</strong></li>\r\n \t<li><strong>If all goes well and you want to continue in astronomy invest in a well-made, high-quality telescope in the 2.5-to-4-inch size range.\r\n</strong>\r\nStudy the telescope manufacturer websites earlier in this chapter or send for catalogs advertised in astronomy magazines. Better yet, talk to experienced astronomy club members if you can. They can advise you on buying a new telescope, and they may know someone who wants to sell a used telescope.</li>\r\n</ol>\r\nYou may be able to borrow a starter telescope and try it out at home. Thanks to the New Hampshire Astronomical Society (NHAS), a movement to place such telescopes in public libraries has begun.\r\n\r\nAstronomy clubs purchase the telescopes; club members modify them for use by inexperienced borrowers and then donate them to the libraries. The telescope model adopted for this project is the Orion StarBlast 4.5, which retails for about $210. It's meant for use on a tabletop but may work for you when just placed on the ground.\r\n\r\nAccording to <em>Sky & Telescope</em>, by late 2016, NHAS had placed more than 100 of these telescopes in New Hampshire libraries, and the St. Louis Astronomical Society had placed over 130 in Missouri and Illinois libraries. Astronomy clubs in other areas are beginning to sponsor library telescopes; search the web to see whether a library telescope program exists near you. Who knows; you may have a (star) blast!\r\n\r\nIf you find that you enjoy astronomy, after a few years, consider moving up to a 6- or 8-inch telescope. It may be harder to use, but you'll be ready to master it after you have some experience. Equipped with a larger telescope, you can see many more stars and other objects.\r\n\r\nYou can get ideas about what larger telescopes to consider by talking to other amateur astronomers and by attending a star party, where you can see many different telescopes in operation and on display.","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}}],"primaryCategoryTaxonomy":{"categoryId":33758,"title":"Astronomy","slug":"astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"secondaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"tertiaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"trendingArticles":null,"inThisArticle":[],"relatedArticles":{"fromBook":[{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246756,"title":"How To Watch Meteor Showers","slug":"viewing-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246756"}},{"articleId":246753,"title":"Spotting Sporadic Meteors, Fireballs, and Bolides","slug":"spotting-sporadic-meteors-fireballs-bolides","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246753"}}],"fromCategory":[{"articleId":300371,"title":"The Autumnal Equinox Marks Our Seasonal Transition","slug":"the-autumnal-equinox-marks-the-transition-to-fall","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/300371"}},{"articleId":292167,"title":"The Magic of the Moon and the Total Lunar Eclipse","slug":"dont-miss-out-on-this-months-lunar-eclipse","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/292167"}},{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}}]},"hasRelatedBookFromSearch":false,"relatedBook":{"bookId":281963,"slug":"astronomy-for-dummies","isbn":"9781394163076","categoryList":["academics-the-arts","science","astronomy"],"amazon":{"default":"//www.amazon.com/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","ca":"//www.amazon.ca/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","indigo_ca":"//www.tkqlhce.com/click-9208661-13710633?url=//www.chapters.indigo.ca/en-ca/books/product/139416307X-item.html&cjsku=978111945484","gb":"//www.amazon.co.uk/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","de":"//www.amazon.de/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20"},"image":{"src":"//coursofppt.com/wp-content/uploads/astronomy-for-dummies-5th-edition-cover-9781394163076-202x255.jpg","width":202,"height":255},"title":"Astronomy For Dummies","testBankPinActivationLink":"//testbanks.wiley.com","bookOutOfPrint":true,"authorsInfo":"<p><p><b><b data-author-id=\"9879\">Stephen P. Maran</b>, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects.</p>","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. 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But digital meteor photography requires a digital single lens reflex camera (DSLR), which is an expensive camera (point-and-shoot cameras and cellphone cameras don't work very well, except in the rare case when you can catch a brilliant fireball) and a lot of trial-and-error experimenting until you get it right.\r\n\r\nFurther, you need a DSLR that you can set for time exposures and that accepts a cable for an intervalometer or \"remote switch with digital timer.\"\r\n\r\nYou might need to spend more on a suitable camera for meteor photography than on a decent small telescope for other observations, but the camera can be used for other purposes, not just your astronomy hobby.\r\n\r\nHere are some important guidelines for digital meteor photography:\r\n<ul>\r\n \t<li>Observe from as dark a location as possible, away from urban lighting.</li>\r\n \t<li>Try meteor photography only when the Moon is below the horizon.</li>\r\n \t<li>Use a sturdy tripod so the camera doesn't shake during a time exposure.</li>\r\n \t<li>Use a wide-angle lens (because you'll catch more meteors in a single shot than with a normal lens) and set it on Infinity. Don't use a telephoto lens.</li>\r\n \t<li>Use an intervalometer or \"remote switch with digital timer\" to operate the camera shutter without shaking the camera and to take pictures at regular intervals during the night.</li>\r\n \t<li>Point the camera about halfway up the sky from the horizon to the zenith, or a little higher, facing whichever direction has the least interfering sky glow from city or other lights.</li>\r\n \t<li>\r\n<p class=\"first-para\">Spend some time making test exposures to determine what settings to use on that particular night. (The best settings vary depending on how bright the sky is.) Make several 10-second exposures, some 20-second exposures, and some 30-second exposures. You're trying to determine how long you can let an exposure last (the longer the better) without skylight overexposing the picture.</p>\r\n<p class=\"child-para\">You may need to repeat this series of time exposures for each of two or three ISO settings. (With a larger ISO setting, you can record fainter meteors, which means more meteors, but with the larger ISO setting, the sky overexposes sooner, so you can't expose for as long a time.) With experience, you should find the \"sweet spot\" of exposure time and ISO that works best with your lens at your location.</p>\r\n</li>\r\n \t<li>For more info on digital meteor photography read this <a href=\"//www.amsmeteors.org/meteor-showers/how-to-photograph-meteors-with-a-dslr/\" target=\"_blank\" rel=\"noopener\">expert advice</a>.</li>\r\n</ul>\r\nYou can photograph sporadic meteors by following the preceding guidelines, but there aren't many sporadic meteors to catch on any given night. A meteor shower offers you the opportunity to snap more meteors, as long as the Moon isn't in the sky. With moonlight, you'll catch far fewer meteors, if any.\r\n\r\nWhen photographing a meteor shower, take the photographs when the shower radiant (the constellation from which the meteor shower seems to come) is well above the horizon, preferably 40 degrees or more. The horizon is at 0 degrees altitude, and the zenith (overhead point) is 90 degrees up, so the halfway point between them is at 45 degrees; two-thirds of the way up is 60 degrees, and so on.","description":"Digital cameras are now the preferred tools for photographing meteors. But digital meteor photography requires a digital single lens reflex camera (DSLR), which is an expensive camera (point-and-shoot cameras and cellphone cameras don't work very well, except in the rare case when you can catch a brilliant fireball) and a lot of trial-and-error experimenting until you get it right.\r\n\r\nFurther, you need a DSLR that you can set for time exposures and that accepts a cable for an intervalometer or \"remote switch with digital timer.\"\r\n\r\nYou might need to spend more on a suitable camera for meteor photography than on a decent small telescope for other observations, but the camera can be used for other purposes, not just your astronomy hobby.\r\n\r\nHere are some important guidelines for digital meteor photography:\r\n<ul>\r\n \t<li>Observe from as dark a location as possible, away from urban lighting.</li>\r\n \t<li>Try meteor photography only when the Moon is below the horizon.</li>\r\n \t<li>Use a sturdy tripod so the camera doesn't shake during a time exposure.</li>\r\n \t<li>Use a wide-angle lens (because you'll catch more meteors in a single shot than with a normal lens) and set it on Infinity. Don't use a telephoto lens.</li>\r\n \t<li>Use an intervalometer or \"remote switch with digital timer\" to operate the camera shutter without shaking the camera and to take pictures at regular intervals during the night.</li>\r\n \t<li>Point the camera about halfway up the sky from the horizon to the zenith, or a little higher, facing whichever direction has the least interfering sky glow from city or other lights.</li>\r\n \t<li>\r\n<p class=\"first-para\">Spend some time making test exposures to determine what settings to use on that particular night. (The best settings vary depending on how bright the sky is.) Make several 10-second exposures, some 20-second exposures, and some 30-second exposures. You're trying to determine how long you can let an exposure last (the longer the better) without skylight overexposing the picture.</p>\r\n<p class=\"child-para\">You may need to repeat this series of time exposures for each of two or three ISO settings. (With a larger ISO setting, you can record fainter meteors, which means more meteors, but with the larger ISO setting, the sky overexposes sooner, so you can't expose for as long a time.) With experience, you should find the \"sweet spot\" of exposure time and ISO that works best with your lens at your location.</p>\r\n</li>\r\n \t<li>For more info on digital meteor photography read this <a href=\"//www.amsmeteors.org/meteor-showers/how-to-photograph-meteors-with-a-dslr/\" target=\"_blank\" rel=\"noopener\">expert advice</a>.</li>\r\n</ul>\r\nYou can photograph sporadic meteors by following the preceding guidelines, but there aren't many sporadic meteors to catch on any given night. A meteor shower offers you the opportunity to snap more meteors, as long as the Moon isn't in the sky. With moonlight, you'll catch far fewer meteors, if any.\r\n\r\nWhen photographing a meteor shower, take the photographs when the shower radiant (the constellation from which the meteor shower seems to come) is well above the horizon, preferably 40 degrees or more. The horizon is at 0 degrees altitude, and the zenith (overhead point) is 90 degrees up, so the halfway point between them is at 45 degrees; two-thirds of the way up is 60 degrees, and so on.","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. 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Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35300"}},{"authorId":35295,"name":"Richard Tresch Fienberg","slug":"richard-tresch-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35295"}}],"_links":{"self":"//dummies-api.coursofppt.com/v2/books/"}},"collections":[],"articleAds":{"footerAd":"<div class=\"du-ad-region row\" id=\"article_page_adhesion_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_adhesion_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-6531990ed5b91\"></div></div>","rightAd":"<div class=\"du-ad-region row\" id=\"article_page_right_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_right_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-6531990ed60cb\"></div></div>"},"articleType":{"articleType":"Articles","articleList":null,"content":null,"videoInfo":{"videoId":null,"name":null,"accountId":null,"playerId":null,"thumbnailUrl":null,"description":null,"uploadDate":null}},"sponsorship":{"sponsorshipPage":false,"backgroundImage":{"src":null,"width":0,"height":0},"brandingLine":"","brandingLink":"","brandingLogo":{"src":null,"width":0,"height":0},"sponsorAd":"","sponsorEbookTitle":"","sponsorEbookLink":"","sponsorEbookImage":{"src":null,"width":0,"height":0}},"primaryLearningPath":"Explore","lifeExpectancy":"Five years","lifeExpectancySetFrom":"2024-10-19T00:00:00+00:00","dummiesForKids":"no","sponsoredContent":"no","adInfo":"","adPairKey":[]},"status":"publish","visibility":"public","articleId":246761},{"headers":{"creationTime":"2018-11-14T08:33:21+00:00","modifiedTime":"2024-10-19T18:50:03+00:00","timestamp":"2024-10-19T21:01:02+00:00"},"data":{"breadcrumbs":[{"name":"Academics & The Arts","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"},"slug":"science","categoryId":33756},{"name":"Astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"},"slug":"astronomy","categoryId":33758}],"title":"Skywatching for Artificial Satellites","strippedTitle":"skywatching for artificial satellites","slug":"skywatching-artificial-satellites","canonicalUrl":"","百度搜引索擎简化":{"metaDescription":"You can see a lot of different artifical satellites orbiting the earth by simply looking up on a clear night. Here's how to find them.","noIndex":0,"noFollow":0},"content":"Hundreds of operating satellites are orbiting Earth, along with thousands of pieces of orbiting space junk — nonfunctional satellites, upper stages from satellite launch rockets, pieces of broken and even exploded satellites, and tiny paint flakes from satellites and rockets.\r\n\r\nYou may be able to glimpse the reflected light from any of the larger satellites and space junk, and powerful defense radar can track even very small pieces.\r\n\r\nThe best way to begin observing artificial satellites is to look for the big ones — such as NASA's International Space Station or the Hubble Space Telescope — and the bright, flashing ones (the dozens of Iridium communication satellites).\r\n<p class=\"article-tips tip\">Looking for a big or bright artificial satellite can be reassuring to the beginning astronomer. Predictions of comets and meteor showers are sometimes mistaken, the comets usually seem fainter than you expect, and usually you see fewer meteors than advertised. But artificial satellite viewing forecasts are usually right on.</p>\r\n<p class=\"article-tips tip\">You can amaze your friends by taking them outside on a clear early evening, glancing at your watch, and saying \"Ho hum, the International Space Station should be coming over about there (point in the right direction as you say this) in just a minute or two.\" And it will!</p>\r\nWant to know what to watch for? Here are some characteristics you can pinpoint for both large and bright satellites:\r\n<ul>\r\n \t<li>\r\n<p class=\"first-para\">A big satellite such as the Hubble Space Telescope or the International Space Station generally appears in the evening as a point of light, moving steadily and noticeably from west to east in the western half of the sky. It moves much too slowly for you to mistake it for a meteor, and it moves much too fast for a comet. You can see it easily with the naked eye, so it can't be an asteroid — and, anyway, it moves much faster than an asteroid.</p>\r\n<p class=\"child-para\">Sometimes you may confuse a high-altitude jet plane with a satellite. But take a look through your binoculars. If the object in view is an airplane, you should be able to distinguish running lights or even the silhouette of the plane against the dim illumination of the night sky. And when your location is quiet, you may be able to hear the plane. You can't hear a satellite.</p>\r\n</li>\r\n \t<li>\r\n<p class=\"first-para\">An Iridium satellite is a wholly different viewing situation: It usually appears as a moving streak of light that gets remarkably bright and then fades after several seconds. It moves much more slowly than a meteor. And an Iridium flare or flash is often brighter than Venus, second in brilliance only to the Moon in the night sky. The Sun, located below your horizon, reflects off one of the door-size, flat, aluminum antennas on the satellite to cause the flash of light. At star parties, people cheer when they spot an Iridium flare, just like when folks see a fireball. You can even see some Iridium flares in daylight.</p>\r\n<p class=\"child-para\">And consider this: More than 60 Iridium satellites are in orbit. They interfere with astronomy, and professional astronomers want them to disappear, but until now, at least, the satellites have had a \"flare\" for entertaining us. A subsequent generation of the satellites, called Iridium NEXT, started being launched into space in January 2017.</p>\r\n<p class=\"child-para\">The NEXT satellites may be next to useless for amateur flare watchers because the design of the antennas has changed so that bright reflections from them are unlikely. The good news is that retiring all the original Iridiums will take a while, so if you start looking soon you may be able to catch some impressive flares before they're just history.</p>\r\n</li>\r\n</ul>","description":"Hundreds of operating satellites are orbiting Earth, along with thousands of pieces of orbiting space junk — nonfunctional satellites, upper stages from satellite launch rockets, pieces of broken and even exploded satellites, and tiny paint flakes from satellites and rockets.\r\n\r\nYou may be able to glimpse the reflected light from any of the larger satellites and space junk, and powerful defense radar can track even very small pieces.\r\n\r\nThe best way to begin observing artificial satellites is to look for the big ones — such as NASA's International Space Station or the Hubble Space Telescope — and the bright, flashing ones (the dozens of Iridium communication satellites).\r\n<p class=\"article-tips tip\">Looking for a big or bright artificial satellite can be reassuring to the beginning astronomer. Predictions of comets and meteor showers are sometimes mistaken, the comets usually seem fainter than you expect, and usually you see fewer meteors than advertised. But artificial satellite viewing forecasts are usually right on.</p>\r\n<p class=\"article-tips tip\">You can amaze your friends by taking them outside on a clear early evening, glancing at your watch, and saying \"Ho hum, the International Space Station should be coming over about there (point in the right direction as you say this) in just a minute or two.\" And it will!</p>\r\nWant to know what to watch for? Here are some characteristics you can pinpoint for both large and bright satellites:\r\n<ul>\r\n \t<li>\r\n<p class=\"first-para\">A big satellite such as the Hubble Space Telescope or the International Space Station generally appears in the evening as a point of light, moving steadily and noticeably from west to east in the western half of the sky. It moves much too slowly for you to mistake it for a meteor, and it moves much too fast for a comet. You can see it easily with the naked eye, so it can't be an asteroid — and, anyway, it moves much faster than an asteroid.</p>\r\n<p class=\"child-para\">Sometimes you may confuse a high-altitude jet plane with a satellite. But take a look through your binoculars. If the object in view is an airplane, you should be able to distinguish running lights or even the silhouette of the plane against the dim illumination of the night sky. And when your location is quiet, you may be able to hear the plane. You can't hear a satellite.</p>\r\n</li>\r\n \t<li>\r\n<p class=\"first-para\">An Iridium satellite is a wholly different viewing situation: It usually appears as a moving streak of light that gets remarkably bright and then fades after several seconds. It moves much more slowly than a meteor. And an Iridium flare or flash is often brighter than Venus, second in brilliance only to the Moon in the night sky. The Sun, located below your horizon, reflects off one of the door-size, flat, aluminum antennas on the satellite to cause the flash of light. At star parties, people cheer when they spot an Iridium flare, just like when folks see a fireball. You can even see some Iridium flares in daylight.</p>\r\n<p class=\"child-para\">And consider this: More than 60 Iridium satellites are in orbit. They interfere with astronomy, and professional astronomers want them to disappear, but until now, at least, the satellites have had a \"flare\" for entertaining us. A subsequent generation of the satellites, called Iridium NEXT, started being launched into space in January 2017.</p>\r\n<p class=\"child-para\">The NEXT satellites may be next to useless for amateur flare watchers because the design of the antennas has changed so that bright reflections from them are unlikely. The good news is that retiring all the original Iridiums will take a while, so if you start looking soon you may be able to catch some impressive flares before they're just history.</p>\r\n</li>\r\n</ul>","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}}],"primaryCategoryTaxonomy":{"categoryId":33758,"title":"Astronomy","slug":"astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"secondaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"tertiaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"trendingArticles":null,"inThisArticle":[],"relatedArticles":{"fromBook":[{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246756,"title":"How To Watch Meteor Showers","slug":"viewing-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246756"}},{"articleId":246753,"title":"Spotting Sporadic Meteors, Fireballs, and Bolides","slug":"spotting-sporadic-meteors-fireballs-bolides","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246753"}},{"articleId":246750,"title":"Planning Your First Steps into Astronomy","slug":"planning-first-steps-astronomy","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246750"}}],"fromCategory":[{"articleId":300371,"title":"The Autumnal Equinox Marks Our Seasonal Transition","slug":"the-autumnal-equinox-marks-the-transition-to-fall","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/300371"}},{"articleId":292167,"title":"The Magic of the Moon and the Total Lunar Eclipse","slug":"dont-miss-out-on-this-months-lunar-eclipse","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/292167"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246756,"title":"How To Watch Meteor Showers","slug":"viewing-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246756"}}]},"hasRelatedBookFromSearch":false,"relatedBook":{"bookId":281963,"slug":"astronomy-for-dummies","isbn":"9781394163076","categoryList":["academics-the-arts","science","astronomy"],"amazon":{"default":"//www.amazon.com/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","ca":"//www.amazon.ca/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","indigo_ca":"//www.tkqlhce.com/click-9208661-13710633?url=//www.chapters.indigo.ca/en-ca/books/product/139416307X-item.html&cjsku=978111945484","gb":"//www.amazon.co.uk/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","de":"//www.amazon.de/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20"},"image":{"src":"//coursofppt.com/wp-content/uploads/astronomy-for-dummies-5th-edition-cover-9781394163076-202x255.jpg","width":202,"height":255},"title":"Astronomy For Dummies","testBankPinActivationLink":"//testbanks.wiley.com","bookOutOfPrint":true,"authorsInfo":"<p><p><b><b data-author-id=\"9879\">Stephen P. Maran</b>, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects.</p>","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35300"}},{"authorId":35295,"name":"Richard Tresch Fienberg","slug":"richard-tresch-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35295"}}],"_links":{"self":"//dummies-api.coursofppt.com/v2/books/"}},"collections":[],"articleAds":{"footerAd":"<div class=\"du-ad-region row\" id=\"article_page_adhesion_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_adhesion_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-6531990ea55e8\"></div></div>","rightAd":"<div class=\"du-ad-region row\" id=\"article_page_right_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_right_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-6531990ea5f8b\"></div></div>"},"articleType":{"articleType":"Articles","articleList":null,"content":null,"videoInfo":{"videoId":null,"name":null,"accountId":null,"playerId":null,"thumbnailUrl":null,"description":null,"uploadDate":null}},"sponsorship":{"sponsorshipPage":false,"backgroundImage":{"src":null,"width":0,"height":0},"brandingLine":"","brandingLink":"","brandingLogo":{"src":null,"width":0,"height":0},"sponsorAd":"","sponsorEbookTitle":"","sponsorEbookLink":"","sponsorEbookImage":{"src":null,"width":0,"height":0}},"primaryLearningPath":"Explore","lifeExpectancy":"Five years","lifeExpectancySetFrom":"2024-10-19T00:00:00+00:00","dummiesForKids":"no","sponsoredContent":"no","adInfo":"","adPairKey":[]},"status":"publish","visibility":"public","articleId":246769},{"headers":{"creationTime":"2018-11-14T07:52:02+00:00","modifiedTime":"2024-10-19T17:19:58+00:00","timestamp":"2024-10-19T18:01:03+00:00"},"data":{"breadcrumbs":[{"name":"Academics & The Arts","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"},"slug":"science","categoryId":33756},{"name":"Astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"},"slug":"astronomy","categoryId":33758}],"title":"Spotting Sporadic Meteors, Fireballs, and Bolides","strippedTitle":"spotting sporadic meteors, fireballs, and bolides","slug":"spotting-sporadic-meteors-fireballs-bolides","canonicalUrl":"","百度搜引索擎简化":{"metaDescription":"Learn the differences between meteroids, meteor showers, fireballs, and bolides, and how to identify them when you see those flashes in the night sky.","noIndex":0,"noFollow":0},"content":"When you're outdoors on a dark night and see a \"shooting star\" (the flash of light from a random, falling meteoroid), what you're probably seeing is a <em>sporadic</em> meteor. But if many meteors appear, all seeming to come from the same place among the stars, you're witnessing a <em>meteor shower.</em> Meteor showers are among the most enjoyable sights in the heavens.\r\n\r\nA dazzlingly bright meteor is a <em>fireball.</em> Although a fireball has no official definition, many astronomers consider a meteor that looks brighter than Venus to be a fireball. However, Venus may not be visible at the time you see the bright meteor. So how can you decide whether you're seeing a fireball?\r\n<p class=\"article-tips tip\">Here's a rule for identifying fireballs: If people facing the meteor all say \"Ooh\" and \"Ah\" (everyone tends to shout when they see a bright meteor), the meteor may be just a bright one. But if people who are facing the wrong way see a momentary bright glow in the sky or on the ground around them, it's the real thing. To paraphrase an old Dean Martin tune, when the meteor hits your eye like a big pizza pie, that's a fireball!</p>\r\nFireballs aren't very rare. If you watch the sky regularly on dark nights for a few hours at a time, you'll probably see a fireball about twice a year. But <em>daylight fireballs</em> are very rare. If the Sun is up and you see a fireball, mark it down as a lucky sighting. You've seen one tremendously bright fireball. When nonscientists see daytime fireballs, they almost always mistake them for an airplane or missile on fire and about to crash.\r\n\r\nAny very bright fireball (approaching the brightness of the half Moon or brighter) or any daylight fireball represents a possibility that the meteoroid producing the light will make it to the ground.\r\n\r\nFreshly fallen meteorites are often of considerable scientific value, and they may be worth good money, too. If you see a fireball that fits this description, write down all the following information so your account can help scientists find the meteorite and determine where it came from:\r\n<ol>\r\n \t<li><strong>Note the time, according to your watch.\r\n</strong>\r\nAt the earliest opportunity, check how fast or slow your watch is running against an accurate time source, such as the <a href=\"//www.time.gov/\" target=\"_blank\" rel=\"noopener\">Official U.S. Time site</a>. If you have a smartphone, it should give you the time accurate at least to the minute.</li>\r\n \t<li><strong>Record exactly where you are.\r\n</strong>\r\nIf you have a Global Positioning System receiver handy (or a smartphone with a GPS app, such as Compass on the iPhone), take a reading of your latitude and longitude. Otherwise, make a simple sketch showing where you stood when you saw the fireball — note roads, buildings, big trees, or any other landmarks.</li>\r\n \t<li><strong>Make a sketch of the sky, showing the track of the fireball with respect to the horizon as you saw it.\r\n</strong>\r\nEven if you're not sure whether you faced southeast or north-northwest, a sketch of your location and the fireball track helps scientists determine the trajectory of the fireball and where the meteoroid may have landed.</li>\r\n</ol>\r\nAfter a daylight fireball or a very bright nighttime fireball, interested scientists advertise for eyewitnesses. They collect the information, and by comparing the accounts of persons who viewed the fireball from different locations, they can close in on the area where it most likely fell to the ground.\r\n\r\nEven a brilliant fireball may be only the size of a small stone — one that would fit easily in the palm of your hand — so scientists need to narrow the search area to have a reasonable chance of finding it. If you don't see a call for information after your fireball observation, chances are good that the nearest planetarium or natural history museum will accept your report and know where to send it.\r\n\r\nOr, report your fireball observation to the <a href=\"//www.amsmeteors.org/\" target=\"_blank\" rel=\"noopener\">American Meteor Society</a> — just look for the prominent \"Report a Fireball\" link on their home page.\r\n\r\nA <em>bolide</em> is a fireball that explodes or produces a loud noise even if it doesn't break apart. Some people use <em>bolide</em> interchangeably with <em>fireball.</em> (You won't find an official agreement on this term; you can find different definitions in even the most authoritative sources.) The noise you hear is the sonic boom from the meteoroid, which is falling through the air faster than the speed of sound.\r\n\r\nWhen a fireball breaks apart, you see two or more bright meteors at once, very close to each other and heading the same way. The meteoroid that produces the fireball has fragmented, probably from aerodynamic forces, just as an airplane falling out of control from high altitude sometimes breaks apart even though it hasn't exploded.\r\n\r\nOften a bright meteor leaves behind a luminous track. The meteor lasts a few seconds or less, but the shining track — or <em>meteor train</em> — may persist for many seconds or even minutes. If it lasts long enough, it becomes distorted by the high-altitude winds, just as the wind gradually deforms the skywriting from an airplane above a beach or stadium.\r\n<p class=\"article-tips remember\">You see more meteors after midnight local time than before because, from midnight to noon, you're on the forward side of Earth, where our planet's plunge through space sweeps up meteoroids. From noon to midnight, you're on the backside, and meteoroids have to catch up in order to enter the atmosphere and become visible.</p>\r\n<p class=\"article-tips remember\">The meteors are like bugs that splatter on your auto windshield. You get many more on the front windshield as you drive down the highway than on the rear windshield because the front windshield is driving into bugs and the rear windshield is driving away from bugs.</p>","description":"When you're outdoors on a dark night and see a \"shooting star\" (the flash of light from a random, falling meteoroid), what you're probably seeing is a <em>sporadic</em> meteor. But if many meteors appear, all seeming to come from the same place among the stars, you're witnessing a <em>meteor shower.</em> Meteor showers are among the most enjoyable sights in the heavens.\r\n\r\nA dazzlingly bright meteor is a <em>fireball.</em> Although a fireball has no official definition, many astronomers consider a meteor that looks brighter than Venus to be a fireball. However, Venus may not be visible at the time you see the bright meteor. So how can you decide whether you're seeing a fireball?\r\n<p class=\"article-tips tip\">Here's a rule for identifying fireballs: If people facing the meteor all say \"Ooh\" and \"Ah\" (everyone tends to shout when they see a bright meteor), the meteor may be just a bright one. But if people who are facing the wrong way see a momentary bright glow in the sky or on the ground around them, it's the real thing. To paraphrase an old Dean Martin tune, when the meteor hits your eye like a big pizza pie, that's a fireball!</p>\r\nFireballs aren't very rare. If you watch the sky regularly on dark nights for a few hours at a time, you'll probably see a fireball about twice a year. But <em>daylight fireballs</em> are very rare. If the Sun is up and you see a fireball, mark it down as a lucky sighting. You've seen one tremendously bright fireball. When nonscientists see daytime fireballs, they almost always mistake them for an airplane or missile on fire and about to crash.\r\n\r\nAny very bright fireball (approaching the brightness of the half Moon or brighter) or any daylight fireball represents a possibility that the meteoroid producing the light will make it to the ground.\r\n\r\nFreshly fallen meteorites are often of considerable scientific value, and they may be worth good money, too. If you see a fireball that fits this description, write down all the following information so your account can help scientists find the meteorite and determine where it came from:\r\n<ol>\r\n \t<li><strong>Note the time, according to your watch.\r\n</strong>\r\nAt the earliest opportunity, check how fast or slow your watch is running against an accurate time source, such as the <a href=\"//www.time.gov/\" target=\"_blank\" rel=\"noopener\">Official U.S. Time site</a>. If you have a smartphone, it should give you the time accurate at least to the minute.</li>\r\n \t<li><strong>Record exactly where you are.\r\n</strong>\r\nIf you have a Global Positioning System receiver handy (or a smartphone with a GPS app, such as Compass on the iPhone), take a reading of your latitude and longitude. Otherwise, make a simple sketch showing where you stood when you saw the fireball — note roads, buildings, big trees, or any other landmarks.</li>\r\n \t<li><strong>Make a sketch of the sky, showing the track of the fireball with respect to the horizon as you saw it.\r\n</strong>\r\nEven if you're not sure whether you faced southeast or north-northwest, a sketch of your location and the fireball track helps scientists determine the trajectory of the fireball and where the meteoroid may have landed.</li>\r\n</ol>\r\nAfter a daylight fireball or a very bright nighttime fireball, interested scientists advertise for eyewitnesses. They collect the information, and by comparing the accounts of persons who viewed the fireball from different locations, they can close in on the area where it most likely fell to the ground.\r\n\r\nEven a brilliant fireball may be only the size of a small stone — one that would fit easily in the palm of your hand — so scientists need to narrow the search area to have a reasonable chance of finding it. If you don't see a call for information after your fireball observation, chances are good that the nearest planetarium or natural history museum will accept your report and know where to send it.\r\n\r\nOr, report your fireball observation to the <a href=\"//www.amsmeteors.org/\" target=\"_blank\" rel=\"noopener\">American Meteor Society</a> — just look for the prominent \"Report a Fireball\" link on their home page.\r\n\r\nA <em>bolide</em> is a fireball that explodes or produces a loud noise even if it doesn't break apart. Some people use <em>bolide</em> interchangeably with <em>fireball.</em> (You won't find an official agreement on this term; you can find different definitions in even the most authoritative sources.) The noise you hear is the sonic boom from the meteoroid, which is falling through the air faster than the speed of sound.\r\n\r\nWhen a fireball breaks apart, you see two or more bright meteors at once, very close to each other and heading the same way. The meteoroid that produces the fireball has fragmented, probably from aerodynamic forces, just as an airplane falling out of control from high altitude sometimes breaks apart even though it hasn't exploded.\r\n\r\nOften a bright meteor leaves behind a luminous track. The meteor lasts a few seconds or less, but the shining track — or <em>meteor train</em> — may persist for many seconds or even minutes. If it lasts long enough, it becomes distorted by the high-altitude winds, just as the wind gradually deforms the skywriting from an airplane above a beach or stadium.\r\n<p class=\"article-tips remember\">You see more meteors after midnight local time than before because, from midnight to noon, you're on the forward side of Earth, where our planet's plunge through space sweeps up meteoroids. From noon to midnight, you're on the backside, and meteoroids have to catch up in order to enter the atmosphere and become visible.</p>\r\n<p class=\"article-tips remember\">The meteors are like bugs that splatter on your auto windshield. You get many more on the front windshield as you drive down the highway than on the rear windshield because the front windshield is driving into bugs and the rear windshield is driving away from bugs.</p>","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}}],"primaryCategoryTaxonomy":{"categoryId":33758,"title":"Astronomy","slug":"astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"secondaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"tertiaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"trendingArticles":null,"inThisArticle":[],"relatedArticles":{"fromBook":[{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246756,"title":"How To Watch Meteor Showers","slug":"viewing-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246756"}},{"articleId":246750,"title":"Planning Your First Steps into Astronomy","slug":"planning-first-steps-astronomy","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246750"}}],"fromCategory":[{"articleId":300371,"title":"The Autumnal Equinox Marks Our Seasonal Transition","slug":"the-autumnal-equinox-marks-the-transition-to-fall","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/300371"}},{"articleId":292167,"title":"The Magic of the Moon and the Total Lunar Eclipse","slug":"dont-miss-out-on-this-months-lunar-eclipse","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/292167"}},{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}}]},"hasRelatedBookFromSearch":false,"relatedBook":{"bookId":281963,"slug":"astronomy-for-dummies","isbn":"9781394163076","categoryList":["academics-the-arts","science","astronomy"],"amazon":{"default":"//www.amazon.com/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","ca":"//www.amazon.ca/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","indigo_ca":"//www.tkqlhce.com/click-9208661-13710633?url=//www.chapters.indigo.ca/en-ca/books/product/139416307X-item.html&cjsku=978111945484","gb":"//www.amazon.co.uk/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","de":"//www.amazon.de/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20"},"image":{"src":"//coursofppt.com/wp-content/uploads/astronomy-for-dummies-5th-edition-cover-9781394163076-202x255.jpg","width":202,"height":255},"title":"Astronomy For Dummies","testBankPinActivationLink":"//testbanks.wiley.com","bookOutOfPrint":true,"authorsInfo":"<p><p><b><b data-author-id=\"9879\">Stephen P. Maran</b>, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects.</p>","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35300"}},{"authorId":35295,"name":"Richard Tresch Fienberg","slug":"richard-tresch-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35295"}}],"_links":{"self":"//dummies-api.coursofppt.com/v2/books/"}},"collections":[],"articleAds":{"footerAd":"<div class=\"du-ad-region row\" id=\"article_page_adhesion_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_adhesion_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-65316edf239e2\"></div></div>","rightAd":"<div class=\"du-ad-region row\" id=\"article_page_right_ad\"><div class=\"du-ad-unit col-md-12\" data-slot-id=\"article_page_right_ad\" data-refreshed=\"false\" \r\n data-target = \"[{&quot;key&quot;:&quot;cat&quot;,&quot;values&quot;:[&quot;academics-the-arts&quot;,&quot;science&quot;,&quot;astronomy&quot;]},{&quot;key&quot;:&quot;isbn&quot;,&quot;values&quot;:[&quot;9781394163076&quot;]}]\" id=\"du-slot-65316edf23f4e\"></div></div>"},"articleType":{"articleType":"Articles","articleList":null,"content":null,"videoInfo":{"videoId":null,"name":null,"accountId":null,"playerId":null,"thumbnailUrl":null,"description":null,"uploadDate":null}},"sponsorship":{"sponsorshipPage":false,"backgroundImage":{"src":null,"width":0,"height":0},"brandingLine":"","brandingLink":"","brandingLogo":{"src":null,"width":0,"height":0},"sponsorAd":"","sponsorEbookTitle":"","sponsorEbookLink":"","sponsorEbookImage":{"src":null,"width":0,"height":0}},"primaryLearningPath":"Explore","lifeExpectancy":"Five years","lifeExpectancySetFrom":"2024-10-19T00:00:00+00:00","dummiesForKids":"no","sponsoredContent":"no","adInfo":"","adPairKey":[]},"status":"publish","visibility":"public","articleId":246753},{"headers":{"creationTime":"2018-11-14T03:48:51+00:00","modifiedTime":"2024-09-14T18:01:31+00:00","timestamp":"2024-09-14T21:01:02+00:00"},"data":{"breadcrumbs":[{"name":"Academics & The Arts","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"},"slug":"science","categoryId":33756},{"name":"Astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"},"slug":"astronomy","categoryId":33758}],"title":"10 Strange Facts about Astronomy and Space","strippedTitle":"10 strange facts about astronomy and space","slug":"10-strange-facts-astronomy-space","canonicalUrl":"","百度搜引索擎简化":{"metaDescription":"The 10 facts about our universe and the study of it are fascinating, and may just spark your interest enough to investigate further.","noIndex":0,"noFollow":0},"content":"Here are some favorite facts about astronomy and, in particular, Earth and its solar system. With the following information under your belt, you may be ready to handle the astronomy questions on television quiz shows and inquiries from friends and family.\r\n<h2 id=\"tab1\" >You have tiny meteorites in your hair</h2>\r\n<em>Micrometeorites,</em> tiny particles from space visible only through microscopes, are constantly raining down on Earth. Some fall on you whenever you go outdoors. But without the most advanced laboratory equipment and analysis techniques, you can't detect them. They get lost in the great mass of pollen, smog particles, household dust, and dandruff that resides on the top of your head.\r\n<h2 id=\"tab2\" >A comet's tail often leads the way</h2>\r\nA comet tail isn't like a horse tail, which always trails behind as the horse gallops ahead. A comet tail always points away from the Sun. When a comet approaches the Sun, its tail, or tails, stream behind it; when the comet heads back out into the solar system, the tail leads the way.\r\n<h2 id=\"tab3\" >Earth is made of rare and unusual matter</h2>\r\nThe great majority of all the matter in the universe is so-called <em>dark matter,</em> invisible stuff that astronomers haven't yet identified. And most ordinary or visible matter is in the form of plasma (hot, electrified gas that makes up normal stars such as the Sun) or degenerate matter (in which atoms or even the nuclei within the atoms are crushed together to unimaginable density, as found in white dwarfs and neutron stars). You don't find dark matter, degenerate matter, or much plasma on Earth. Compared to the great bulk of the universe, Earth and earthlings are the aliens.\r\n<h2 id=\"tab4\" >High tide comes on both sides of Earth at the same time</h2>\r\nOcean tides on the side of Earth that faces the Moon aren't appreciably higher than tides on the opposite side of Earth at the same time. This may defy common sense, but not physics and mathematical analysis. (The same goes for the smaller ocean tides raised by the Sun.)\r\n\r\n[caption id=\"attachment_262291\" align=\"alignnone\" width=\"535\"]<img class=\"wp-image-262291 size-full\" src=\"//coursofppt.com/wp-content/uploads/astronomy-space-facts.jpg\" alt=\"astronomy space\" width=\"535\" height=\"357\" /> © Shutterstock/AstroStar[/caption]\r\n<h2 id=\"tab5\" >On Venus, the rain never falls on the plain</h2>\r\nIn fact, the constant rain on Venus never falls on anything. It evaporates before it hits the ground, and the rain is pure acid. (The common name for evaporating rain is <em>virga</em>.)\r\n<h2 id=\"tab6\" >Rocks from Mars dot Earth</h2>\r\nPeople have found about 100 meteorites on Earth that come from the crust of Mars, blasted from that planet by the impacts of much larger objects — perhaps from the asteroid belt. Statistically, many more undiscovered Mars rocks must have fallen into the ocean or landed in out-of-the-way places where they haven't been spotted.\r\n<h2 id=\"tab7\" >Pluto was discovered from predictions of a false theory</h2>\r\nPercival Lowell predicted the existence and approximate location of the object that we now call Pluto. When Clyde Tombaugh surveyed the designated region, he discovered Pluto. But now scientists know that Lowell's theory, which inferred the existence of Pluto from its gravitational effects on the motion of Uranus, was wrong.\r\n\r\nIn fact, Pluto's mass is much too small to produce the \"observed\" effects. Furthermore, the \"gravitational effects\" were just errors in measuring the motion of Uranus. (Not enough information was available about Neptune's motion to study it for clues.)\r\n\r\nThe discovery of Pluto took hard work, but as it happened, it was just plain luck. And although Lowell predicted the existence of a planet, as Pluto was first termed, the International Astronomical Union has since downgraded it to dwarf planet.\r\n<h2 id=\"tab8\" >Sunspots aren't dark</h2>\r\nAlmost everyone \"knows\" that sunspots are \"dark\" spots on the Sun. But in reality, sunspots are simply places where the hot solar gas is slightly cooler than its surroundings. The spots look dark compared to their hotter surroundings, but if all you can see is the sunspot, it looks bright.\r\n<h2 id=\"tab9\" >A star in plain view may have exploded, but no one knows</h2>\r\nEta Carinae is one of the most massive, fiercely shining stars in our galaxy, and astronomers expect it to produce a powerful supernova explosion at any time, if it hasn't already. But because light takes about 8,000 years to travel from Eta Carinae to Earth, an explosion that occurred many years ago isn't visible to us yet.\r\n<h2 id=\"tab10\" >You might have seen the Big Bang on an old TV set</h2>\r\n<em>The Big Bang Theory</em> premiered in 2007, but the real Big Bang may have made its TV debut even before that. Some of the <em>snow</em> — a pattern of interference that looks like little white spots or streaks on old black-and-white television sets — was actually radio waves the TV antenna received from the cosmic microwave background, a glow from the early universe in the aftermath of the Big Bang.\r\n\r\nWhen this radiation was actually discovered at the Bell Telephone Laboratories, scientists studied many possible causes of the unexpected \"noise\" in the radio receiver. They even investigated pigeon droppings, or \"white dielectric material\" in science speak, as a possible cause but later dropped that suggestion.","description":"Here are some favorite facts about astronomy and, in particular, Earth and its solar system. With the following information under your belt, you may be ready to handle the astronomy questions on television quiz shows and inquiries from friends and family.\r\n<h2 id=\"tab1\" >You have tiny meteorites in your hair</h2>\r\n<em>Micrometeorites,</em> tiny particles from space visible only through microscopes, are constantly raining down on Earth. Some fall on you whenever you go outdoors. But without the most advanced laboratory equipment and analysis techniques, you can't detect them. They get lost in the great mass of pollen, smog particles, household dust, and dandruff that resides on the top of your head.\r\n<h2 id=\"tab2\" >A comet's tail often leads the way</h2>\r\nA comet tail isn't like a horse tail, which always trails behind as the horse gallops ahead. A comet tail always points away from the Sun. When a comet approaches the Sun, its tail, or tails, stream behind it; when the comet heads back out into the solar system, the tail leads the way.\r\n<h2 id=\"tab3\" >Earth is made of rare and unusual matter</h2>\r\nThe great majority of all the matter in the universe is so-called <em>dark matter,</em> invisible stuff that astronomers haven't yet identified. And most ordinary or visible matter is in the form of plasma (hot, electrified gas that makes up normal stars such as the Sun) or degenerate matter (in which atoms or even the nuclei within the atoms are crushed together to unimaginable density, as found in white dwarfs and neutron stars). You don't find dark matter, degenerate matter, or much plasma on Earth. Compared to the great bulk of the universe, Earth and earthlings are the aliens.\r\n<h2 id=\"tab4\" >High tide comes on both sides of Earth at the same time</h2>\r\nOcean tides on the side of Earth that faces the Moon aren't appreciably higher than tides on the opposite side of Earth at the same time. This may defy common sense, but not physics and mathematical analysis. (The same goes for the smaller ocean tides raised by the Sun.)\r\n\r\n[caption id=\"attachment_262291\" align=\"alignnone\" width=\"535\"]<img class=\"wp-image-262291 size-full\" src=\"//coursofppt.com/wp-content/uploads/astronomy-space-facts.jpg\" alt=\"astronomy space\" width=\"535\" height=\"357\" /> © Shutterstock/AstroStar[/caption]\r\n<h2 id=\"tab5\" >On Venus, the rain never falls on the plain</h2>\r\nIn fact, the constant rain on Venus never falls on anything. It evaporates before it hits the ground, and the rain is pure acid. (The common name for evaporating rain is <em>virga</em>.)\r\n<h2 id=\"tab6\" >Rocks from Mars dot Earth</h2>\r\nPeople have found about 100 meteorites on Earth that come from the crust of Mars, blasted from that planet by the impacts of much larger objects — perhaps from the asteroid belt. Statistically, many more undiscovered Mars rocks must have fallen into the ocean or landed in out-of-the-way places where they haven't been spotted.\r\n<h2 id=\"tab7\" >Pluto was discovered from predictions of a false theory</h2>\r\nPercival Lowell predicted the existence and approximate location of the object that we now call Pluto. When Clyde Tombaugh surveyed the designated region, he discovered Pluto. But now scientists know that Lowell's theory, which inferred the existence of Pluto from its gravitational effects on the motion of Uranus, was wrong.\r\n\r\nIn fact, Pluto's mass is much too small to produce the \"observed\" effects. Furthermore, the \"gravitational effects\" were just errors in measuring the motion of Uranus. (Not enough information was available about Neptune's motion to study it for clues.)\r\n\r\nThe discovery of Pluto took hard work, but as it happened, it was just plain luck. And although Lowell predicted the existence of a planet, as Pluto was first termed, the International Astronomical Union has since downgraded it to dwarf planet.\r\n<h2 id=\"tab8\" >Sunspots aren't dark</h2>\r\nAlmost everyone \"knows\" that sunspots are \"dark\" spots on the Sun. But in reality, sunspots are simply places where the hot solar gas is slightly cooler than its surroundings. The spots look dark compared to their hotter surroundings, but if all you can see is the sunspot, it looks bright.\r\n<h2 id=\"tab9\" >A star in plain view may have exploded, but no one knows</h2>\r\nEta Carinae is one of the most massive, fiercely shining stars in our galaxy, and astronomers expect it to produce a powerful supernova explosion at any time, if it hasn't already. But because light takes about 8,000 years to travel from Eta Carinae to Earth, an explosion that occurred many years ago isn't visible to us yet.\r\n<h2 id=\"tab10\" >You might have seen the Big Bang on an old TV set</h2>\r\n<em>The Big Bang Theory</em> premiered in 2007, but the real Big Bang may have made its TV debut even before that. Some of the <em>snow</em> — a pattern of interference that looks like little white spots or streaks on old black-and-white television sets — was actually radio waves the TV antenna received from the cosmic microwave background, a glow from the early universe in the aftermath of the Big Bang.\r\n\r\nWhen this radiation was actually discovered at the Bell Telephone Laboratories, scientists studied many possible causes of the unexpected \"noise\" in the radio receiver. They even investigated pigeon droppings, or \"white dielectric material\" in science speak, as a possible cause but later dropped that suggestion.","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. 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Maran</b>, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects.</p>","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. 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For those of us in the Northern Hemisphere, it’s the time of the year when temperatures cool off, birds begin gathering for migration, and the trees start showing color.\r\n\r\n[caption id=\"attachment_300373\" align=\"alignnone\" width=\"630\"]<img class=\"size-full wp-image-300373\" src=\"//coursofppt.com/wp-content/uploads/solstice-equinox-seasons-adobeStock_377108658.jpg\" alt=\"\" width=\"630\" height=\"485\" /> Yusufdemirci / Adobe Stock[/caption]\r\n\r\nAll of this occurs around the autumnal equinox, between September 21 and September 24 (in 2023, the equinox is the 23<sup>rd</sup>) marking the start of fall for people in the Northern Hemisphere.\r\n<h2 id=\"tab1\" ><strong>Earth’s tilt and orbit make it all happen</strong></h2>\r\nOur planet is tilted about 23.5 degrees on its axis as it travels around the sun, and it stays tilted in the same direction as it orbits. This means the sun’s light hits the Earth at different angles. So, different parts of the Earth receive varying amounts of the sun’s light and warmth throughout the year — in other words, we have seasons.\r\n\r\nHowever, twice during Earth’s orbit, on the autumnal (September) equinox and the vernal, or spring (March), equinox, the sun is directly over the planet’s equator, and everybody across the globe experiences a nearly equal amount of daylight and darkness.\r\n\r\nA few interesting facts about the equinoxes and Earth’s orbit:\r\n<ul>\r\n \t<li>The word equinox comes from two Latin words: <em>aequus</em> (equal) and <em>nox</em> (night).</li>\r\n \t<li>During the autumnal and vernal equinoxes, people across the globe can see the sun rise above the horizon due east and set due west. So, it’s a good time to find due east and west.</li>\r\n \t<li>Because of the Earth’s tilt on its axis, its northern and southern hemispheres trade places throughout the year receiving the sun’s light and warmth most directly.</li>\r\n \t<li>For people in the Southern Hemisphere, the equinoxes signal the opposite seasonal transitions: September marks the beginning of spring, and the March equinox marks the beginning of autumn.</li>\r\n \t<li>If you live in the Northern Hemisphere, starting on the autumnal equinox, you can observe a slight daily change in the sun’s arc across the sky — it’s shifting to the south.</li>\r\n \t<li>A number of prehistoric sites, like Stonehenge and Newgrange in the United Kingdom, were possibly used by ancient cultures to predict equinoxes and the summer and winter <em>solstices</em> — the longest and shortest days of sunlight during the year).</li>\r\n</ul>\r\n<p class=\"article-tips tip\">To learn more about the Earth's orbit, our solar system, the stars, and beyond, check out <a href=\"//coursofppt.com/book/academics-the-arts/science/astronomy/astronomy-for-dummies-281963/\">the fifth edition of Astronomy For Dummies</a>.</p>\r\n\r\n<h2 id=\"tab2\" ><strong>Celebrations around the fall equinox</strong></h2>\r\nOver the centuries, before humans could scientifically explain the autumnal equinox, they observed the sun’s changing position in the sky and nature's transitions in the fall and spring, and they marked these times with rituals and celebrations.\r\n\r\nSome of these ancient observations were incorporated into Greek mythology and other cultures' mythology, and into religious practices. Today, there are still many cultural and religious traditions practiced around the equinoxes. Here are summaries of just a few:\r\n<ul>\r\n \t<li><strong>Mabon — United Kingdom: </strong>Mabon is a fall equinox tradition created by the ancient Celtic people and celebrated by pagans today. It is one of the oldest harvest festivals in Europe. Acknowledging the autumnal equinox, the holiday is meant to give thanks for the warm, summer months, the fall harvest, and to get ready for the beginning of winter.</li>\r\n \t<li>\r\n<p class=\"first-para\"><strong>The Snake of Sunlight — Mexico: </strong>The ancient Mayan and Aztec civilizations in Mexico celebrated the equinoxes at the site of Chichen-Itza, a city that existed about 1,500 years ago in what is now the state of Yucatan. When you visit the Chichen-Itza ruins today, you see a massive pyramid, a monument the Mayans built to honor the god Kulkulcan (Quetzalcoatl to the Aztecs). The deity was a feathered serpent, and the ancient Mayans believed it visited the temple twice a year — on the autumn and spring equinoxes.</p>\r\n<p class=\"child-para\">Chichen-Itza is a popular tourist attraction, and many come to witness a special effect that happens on the equinoxes. The pyramid’s steps are oriented so that in the afternoon of the two equinox days, the shadow on the pyramid looks like a snake slowly slithering down the stairs, with its tail at the top and its head at the bottom.</p>\r\n</li>\r\n \t<li>\r\n<p class=\"first-para\"><strong>Higan — Japan: </strong>Higan is a Buddhist tradition taking place around the equinoxes – three days before the equinox day and three days after. <em>Higan</em> means crossing over to the “other shore,” symbolizing the world of enlightenment, or spiritual awakening.</p>\r\n<p class=\"child-para\">For Buddhists, Higan is a time to reflect on one’s life and renew religious practices. During Higan in Japan, people visit their ancestors’ graves, where they tidy up the gravesites and place flowers and incense.</p>\r\n</li>\r\n</ul>","description":"You’ve probably noticed that September just “feels” like a time of transition. For those of us in the Northern Hemisphere, it’s the time of the year when temperatures cool off, birds begin gathering for migration, and the trees start showing color.\r\n\r\n[caption id=\"attachment_300373\" align=\"alignnone\" width=\"630\"]<img class=\"size-full wp-image-300373\" src=\"//coursofppt.com/wp-content/uploads/solstice-equinox-seasons-adobeStock_377108658.jpg\" alt=\"\" width=\"630\" height=\"485\" /> Yusufdemirci / Adobe Stock[/caption]\r\n\r\nAll of this occurs around the autumnal equinox, between September 21 and September 24 (in 2023, the equinox is the 23<sup>rd</sup>) marking the start of fall for people in the Northern Hemisphere.\r\n<h2 id=\"tab1\" ><strong>Earth’s tilt and orbit make it all happen</strong></h2>\r\nOur planet is tilted about 23.5 degrees on its axis as it travels around the sun, and it stays tilted in the same direction as it orbits. This means the sun’s light hits the Earth at different angles. So, different parts of the Earth receive varying amounts of the sun’s light and warmth throughout the year — in other words, we have seasons.\r\n\r\nHowever, twice during Earth’s orbit, on the autumnal (September) equinox and the vernal, or spring (March), equinox, the sun is directly over the planet’s equator, and everybody across the globe experiences a nearly equal amount of daylight and darkness.\r\n\r\nA few interesting facts about the equinoxes and Earth’s orbit:\r\n<ul>\r\n \t<li>The word equinox comes from two Latin words: <em>aequus</em> (equal) and <em>nox</em> (night).</li>\r\n \t<li>During the autumnal and vernal equinoxes, people across the globe can see the sun rise above the horizon due east and set due west. So, it’s a good time to find due east and west.</li>\r\n \t<li>Because of the Earth’s tilt on its axis, its northern and southern hemispheres trade places throughout the year receiving the sun’s light and warmth most directly.</li>\r\n \t<li>For people in the Southern Hemisphere, the equinoxes signal the opposite seasonal transitions: September marks the beginning of spring, and the March equinox marks the beginning of autumn.</li>\r\n \t<li>If you live in the Northern Hemisphere, starting on the autumnal equinox, you can observe a slight daily change in the sun’s arc across the sky — it’s shifting to the south.</li>\r\n \t<li>A number of prehistoric sites, like Stonehenge and Newgrange in the United Kingdom, were possibly used by ancient cultures to predict equinoxes and the summer and winter <em>solstices</em> — the longest and shortest days of sunlight during the year).</li>\r\n</ul>\r\n<p class=\"article-tips tip\">To learn more about the Earth's orbit, our solar system, the stars, and beyond, check out <a href=\"//coursofppt.com/book/academics-the-arts/science/astronomy/astronomy-for-dummies-281963/\">the fifth edition of Astronomy For Dummies</a>.</p>\r\n\r\n<h2 id=\"tab2\" ><strong>Celebrations around the fall equinox</strong></h2>\r\nOver the centuries, before humans could scientifically explain the autumnal equinox, they observed the sun’s changing position in the sky and nature's transitions in the fall and spring, and they marked these times with rituals and celebrations.\r\n\r\nSome of these ancient observations were incorporated into Greek mythology and other cultures' mythology, and into religious practices. Today, there are still many cultural and religious traditions practiced around the equinoxes. Here are summaries of just a few:\r\n<ul>\r\n \t<li><strong>Mabon — United Kingdom: </strong>Mabon is a fall equinox tradition created by the ancient Celtic people and celebrated by pagans today. It is one of the oldest harvest festivals in Europe. Acknowledging the autumnal equinox, the holiday is meant to give thanks for the warm, summer months, the fall harvest, and to get ready for the beginning of winter.</li>\r\n \t<li>\r\n<p class=\"first-para\"><strong>The Snake of Sunlight — Mexico: </strong>The ancient Mayan and Aztec civilizations in Mexico celebrated the equinoxes at the site of Chichen-Itza, a city that existed about 1,500 years ago in what is now the state of Yucatan. When you visit the Chichen-Itza ruins today, you see a massive pyramid, a monument the Mayans built to honor the god Kulkulcan (Quetzalcoatl to the Aztecs). The deity was a feathered serpent, and the ancient Mayans believed it visited the temple twice a year — on the autumn and spring equinoxes.</p>\r\n<p class=\"child-para\">Chichen-Itza is a popular tourist attraction, and many come to witness a special effect that happens on the equinoxes. The pyramid’s steps are oriented so that in the afternoon of the two equinox days, the shadow on the pyramid looks like a snake slowly slithering down the stairs, with its tail at the top and its head at the bottom.</p>\r\n</li>\r\n \t<li>\r\n<p class=\"first-para\"><strong>Higan — Japan: </strong>Higan is a Buddhist tradition taking place around the equinoxes – three days before the equinox day and three days after. <em>Higan</em> means crossing over to the “other shore,” symbolizing the world of enlightenment, or spiritual awakening.</p>\r\n<p class=\"child-para\">For Buddhists, Higan is a time to reflect on one’s life and renew religious practices. During Higan in Japan, people visit their ancestors’ graves, where they tidy up the gravesites and place flowers and incense.</p>\r\n</li>\r\n</ul>","blurb":"","authors":[{"authorId":8947,"name":"The Experts at Dummies","slug":"the-experts-at-dummies","description":"The Experts at Dummies are smart, friendly people who make learning easy by taking a not-so-serious approach to serious stuff.","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/8947"}}],"primaryCategoryTaxonomy":{"categoryId":33758,"title":"Astronomy","slug":"astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"secondaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"tertiaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"trendingArticles":null,"inThisArticle":[{"label":"Earth’s tilt and orbit make it all happen","target":"#tab1"},{"label":"Celebrations around the fall equinox","target":"#tab2"}],"relatedArticles":{"fromBook":[],"fromCategory":[{"articleId":292167,"title":"The Magic of the Moon and the Total Lunar Eclipse","slug":"dont-miss-out-on-this-months-lunar-eclipse","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/292167"}},{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor 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Arts","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33662"},"slug":"academics-the-arts","categoryId":33662},{"name":"Science","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33756"},"slug":"science","categoryId":33756},{"name":"Astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"},"slug":"astronomy","categoryId":33758}],"title":"How To Watch Meteor Showers","strippedTitle":"how to watch meteor showers","slug":"viewing-meteor-showers","canonicalUrl":"","百度搜引索擎简化":{"metaDescription":"Learn how to get the most out of viewing the next meteor shower, including when they happen and how to best track the meteors.","noIndex":0,"noFollow":0},"content":"Normally, only a few meteors per hour are visible — more after midnight than before and (for observers in the Northern Hemisphere) more in the fall than in the spring. But on certain occasions every year, you may see 10, 20, or even 50 or more meteors per hour in a dark, moonless sky far from city lights. Such an event is a <em>meteor shower,</em> when Earth passes through a great ring of billions of meteoroids that runs all the way around the orbit of the comet that shed them.\r\n\r\nThe following figure illustrates the occurrence of a meteor shower.\r\n\r\n[caption id=\"attachment_246757\" align=\"alignnone\" width=\"535\"]<img class=\"size-full wp-image-246757\" src=\"//coursofppt.com/wp-content/uploads/astronomy-meteor-shower.jpg\" alt=\"astronomy-meteor-shower\" width=\"535\" height=\"315\" /> Earth's path crossing a belt of meteoroids creates a shower of meteors.[/caption]\r\n\r\nThe direction in space or place on the sky where a meteor shower seems to come from is called the <em>radiant.</em> The most popular meteor shower is the Perseids, which, at its peak, produces as many as 80 meteors per hour. (The Perseids get their name because they seem to streak across the sky from the direction of the constellation Perseus, the Hero, their radiant. Meteor showers are usually named for constellations or bright stars [such as Eta Aquarii] near their radiants.)\r\n\r\nA few other meteor showers produce as many meteors as the Perseids, but fewer people take the time to observe them. The Perseids come in August, when the balmy nights in North America and Europe often are perfect for skywatching, but the other leading meteor showers — the Geminids and Quadrantids — streak across the sky in December and January, respectively, when the weather is worse in the Northern Hemisphere and observers' ambitions are limited.\r\n\r\nThe table lists the top annual meteor showers. The dates in the table are the nights when the showers usually reach their peak. Some showers go on for days, and others for weeks, raining down meteors at lower rates than the peak values. The Quadrantids may last for just one night or only a few hours.\r\n\r\n<strong>Top Annual Meteor Showers</strong>\r\n<table width=\"658\">\r\n<thead>\r\n<tr>\r\n<td width=\"219\"><strong>Shower Name</strong></td>\r\n<td width=\"219\"><strong>Approximate Date</strong></td>\r\n<td width=\"219\"><strong>Meteor Rate (Per Hour)</strong></td>\r\n</tr>\r\n</thead>\r\n<tbody>\r\n<tr>\r\n<td width=\"219\">Quadrantids</td>\r\n<td width=\"219\">Jan. 3–4</td>\r\n<td width=\"219\">90</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Lyrids</td>\r\n<td width=\"219\">Apr. 21</td>\r\n<td width=\"219\">15</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Eta Aquarids</td>\r\n<td width=\"219\">May 4–5</td>\r\n<td width=\"219\">30</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Delta Aquarids</td>\r\n<td width=\"219\">July 28–29</td>\r\n<td width=\"219\">25</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Perseids</td>\r\n<td width=\"219\">Aug. 12</td>\r\n<td width=\"219\">80</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Orionids</td>\r\n<td width=\"219\">Oct. 21</td>\r\n<td width=\"219\">20</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Geminids</td>\r\n<td width=\"219\">Dec. 13</td>\r\n<td width=\"219\">100</td>\r\n</tr>\r\n</tbody>\r\n</table>\r\n \r\n\r\nThe Quadrantids' radiant is in the northeast corner of the constellation Bootes, the Herdsman. The meteors are named for a constellation found on 19th-century star charts that astronomers no longer officially recognize. In addition to losing their namesake, the Quadrantids seem to have lost the comet that spawned them — their origin was a mystery until 2003, when astronomer Petrus Jenniskens found that an object named 2003 EH<sub>1</sub> may be their parent comet.\r\n\r\nThe Geminids are a meteor shower that seems to be associated with the orbit of an asteroid rather than a comet. However, the \"asteroid\" is probably a dead comet, which no longer puffs out gas and dust to form a head and tail. The object 2003 EH<sub>1</sub>, the likely parent of the Quadrantids, may be a dead comet, too.\r\n\r\nThe Leonids are an unusual meteor shower that occurs around November 17 every year, usually to no great effect. But every 33 years, many more meteors are present than usual, perhaps for several successive Novembers. Huge numbers of Leonids were seen in November 1966 and again in November 1999, 2000, 2001, and 2002, at least for brief times at some locations. The next great display likely will come in 2032. Don't forget to look for it.\r\n\r\nYou almost never see as many meteors per hour as lsited. The official meteor rates are defined for exceptional viewing conditions, which few people experience nowadays. But meteor showers vary from year to year, just like rainfall. Sometimes people do see as many Perseids as listed. On rare occasions, they see many more than expected. Such inconsistency is why keeping accurate records of the meteors that you count can be helpful to the scientific record.\r\n<p class=\"article-tips tip\">For more information on upcoming meteor showers, check out the <a href=\"//www.amsmeteors.org/\" target=\"_blank\" rel=\"noopener\">American Meteor Society website</a>. Do you live south of the equator? If so, check out the list of meteor showers visible from the Southern Hemisphere on the website of the <a href=\"//rasnz.org.nz/in-the-sky/meteor-showers\" target=\"_blank\" rel=\"noopener\">Royal Astronomical Society of New Zealand</a>.</p>\r\nTo track meteors, you need an accurate time source, a way to record your observations, and a dim flashlight to see what you're doing. For the latter, it's best to use a red flashlight, which you can purchase, or make from an ordinary flashlight by wrapping red transparent plastic around the bulb.\r\n\r\nSome astronomers paint the lamp with a thin coat of red nail polish. If you use a white light, you dazzle your eyes and make it impossible to see the fainter stars and meteors for 10 to 30 minutes, depending on the circumstances. Letting your vision adjust to the dark is called getting dark adapted and is a step you want to take every time you observe the night sky.\r\n\r\nThe best way to watch and count meteors is to recline on a lounge chair. (You can do pretty well just lying on a blanket with a pillow, but you're more likely to fall asleep in that position and miss the best part of the show.) Tilt your head so you're looking slightly more than halfway up from the horizon to the zenith — the optimum direction for counting meteors. Take notes. And be sure you have a thermos of hot coffee, tea, or cocoa!\r\n\r\n[caption id=\"attachment_246758\" align=\"alignnone\" width=\"469\"]<img class=\"size-full wp-image-246758\" src=\"//coursofppt.com/wp-content/uploads/astronomy-meteor-viewing.jpg\" alt=\"astronomy-meteor-viewing\" width=\"469\" height=\"400\" /> Tilt your head halfway between the horizon and the zenith for optimum meteor viewing.[/caption]\r\n\r\nYou don't have to face the radiant when you observe a meteor shower, although many people do. The meteors streak all over the sky, and their visible paths may begin and end far from the radiant. But you can visually extrapolate the meteors' paths back in the direction from which they seem to come, and the paths point back to the radiant. Identifying a radiant in that way is how you can tell a shower meteor from a sporadic one.\r\n\r\nIf you do face the radiant, however, you see some meteors that seem to have very short paths, even though they appear fairly bright. The paths appear short because the meteors are coming almost right at you. Fortunately, the shower meteoroids are microscopic and won't make it to the ground.\r\n<p class=\"article-tips tip\">For more information on meteor showers, including historical events, facts, and advice on observing, head to the <a href=\"//skyandtelescope.org/\" target=\"_blank\" rel=\"noopener\">Sky and Telescope site</a> and enter \"Shooting Stars\" in the search window. Then you can download the free Shooting Stars e-book (you may have to register your email address).</p>","description":"Normally, only a few meteors per hour are visible — more after midnight than before and (for observers in the Northern Hemisphere) more in the fall than in the spring. But on certain occasions every year, you may see 10, 20, or even 50 or more meteors per hour in a dark, moonless sky far from city lights. Such an event is a <em>meteor shower,</em> when Earth passes through a great ring of billions of meteoroids that runs all the way around the orbit of the comet that shed them.\r\n\r\nThe following figure illustrates the occurrence of a meteor shower.\r\n\r\n[caption id=\"attachment_246757\" align=\"alignnone\" width=\"535\"]<img class=\"size-full wp-image-246757\" src=\"//coursofppt.com/wp-content/uploads/astronomy-meteor-shower.jpg\" alt=\"astronomy-meteor-shower\" width=\"535\" height=\"315\" /> Earth's path crossing a belt of meteoroids creates a shower of meteors.[/caption]\r\n\r\nThe direction in space or place on the sky where a meteor shower seems to come from is called the <em>radiant.</em> The most popular meteor shower is the Perseids, which, at its peak, produces as many as 80 meteors per hour. (The Perseids get their name because they seem to streak across the sky from the direction of the constellation Perseus, the Hero, their radiant. Meteor showers are usually named for constellations or bright stars [such as Eta Aquarii] near their radiants.)\r\n\r\nA few other meteor showers produce as many meteors as the Perseids, but fewer people take the time to observe them. The Perseids come in August, when the balmy nights in North America and Europe often are perfect for skywatching, but the other leading meteor showers — the Geminids and Quadrantids — streak across the sky in December and January, respectively, when the weather is worse in the Northern Hemisphere and observers' ambitions are limited.\r\n\r\nThe table lists the top annual meteor showers. The dates in the table are the nights when the showers usually reach their peak. Some showers go on for days, and others for weeks, raining down meteors at lower rates than the peak values. The Quadrantids may last for just one night or only a few hours.\r\n\r\n<strong>Top Annual Meteor Showers</strong>\r\n<table width=\"658\">\r\n<thead>\r\n<tr>\r\n<td width=\"219\"><strong>Shower Name</strong></td>\r\n<td width=\"219\"><strong>Approximate Date</strong></td>\r\n<td width=\"219\"><strong>Meteor Rate (Per Hour)</strong></td>\r\n</tr>\r\n</thead>\r\n<tbody>\r\n<tr>\r\n<td width=\"219\">Quadrantids</td>\r\n<td width=\"219\">Jan. 3–4</td>\r\n<td width=\"219\">90</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Lyrids</td>\r\n<td width=\"219\">Apr. 21</td>\r\n<td width=\"219\">15</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Eta Aquarids</td>\r\n<td width=\"219\">May 4–5</td>\r\n<td width=\"219\">30</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Delta Aquarids</td>\r\n<td width=\"219\">July 28–29</td>\r\n<td width=\"219\">25</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Perseids</td>\r\n<td width=\"219\">Aug. 12</td>\r\n<td width=\"219\">80</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Orionids</td>\r\n<td width=\"219\">Oct. 21</td>\r\n<td width=\"219\">20</td>\r\n</tr>\r\n<tr>\r\n<td width=\"219\">Geminids</td>\r\n<td width=\"219\">Dec. 13</td>\r\n<td width=\"219\">100</td>\r\n</tr>\r\n</tbody>\r\n</table>\r\n \r\n\r\nThe Quadrantids' radiant is in the northeast corner of the constellation Bootes, the Herdsman. The meteors are named for a constellation found on 19th-century star charts that astronomers no longer officially recognize. In addition to losing their namesake, the Quadrantids seem to have lost the comet that spawned them — their origin was a mystery until 2003, when astronomer Petrus Jenniskens found that an object named 2003 EH<sub>1</sub> may be their parent comet.\r\n\r\nThe Geminids are a meteor shower that seems to be associated with the orbit of an asteroid rather than a comet. However, the \"asteroid\" is probably a dead comet, which no longer puffs out gas and dust to form a head and tail. The object 2003 EH<sub>1</sub>, the likely parent of the Quadrantids, may be a dead comet, too.\r\n\r\nThe Leonids are an unusual meteor shower that occurs around November 17 every year, usually to no great effect. But every 33 years, many more meteors are present than usual, perhaps for several successive Novembers. Huge numbers of Leonids were seen in November 1966 and again in November 1999, 2000, 2001, and 2002, at least for brief times at some locations. The next great display likely will come in 2032. Don't forget to look for it.\r\n\r\nYou almost never see as many meteors per hour as lsited. The official meteor rates are defined for exceptional viewing conditions, which few people experience nowadays. But meteor showers vary from year to year, just like rainfall. Sometimes people do see as many Perseids as listed. On rare occasions, they see many more than expected. Such inconsistency is why keeping accurate records of the meteors that you count can be helpful to the scientific record.\r\n<p class=\"article-tips tip\">For more information on upcoming meteor showers, check out the <a href=\"//www.amsmeteors.org/\" target=\"_blank\" rel=\"noopener\">American Meteor Society website</a>. Do you live south of the equator? If so, check out the list of meteor showers visible from the Southern Hemisphere on the website of the <a href=\"//rasnz.org.nz/in-the-sky/meteor-showers\" target=\"_blank\" rel=\"noopener\">Royal Astronomical Society of New Zealand</a>.</p>\r\nTo track meteors, you need an accurate time source, a way to record your observations, and a dim flashlight to see what you're doing. For the latter, it's best to use a red flashlight, which you can purchase, or make from an ordinary flashlight by wrapping red transparent plastic around the bulb.\r\n\r\nSome astronomers paint the lamp with a thin coat of red nail polish. If you use a white light, you dazzle your eyes and make it impossible to see the fainter stars and meteors for 10 to 30 minutes, depending on the circumstances. Letting your vision adjust to the dark is called getting dark adapted and is a step you want to take every time you observe the night sky.\r\n\r\nThe best way to watch and count meteors is to recline on a lounge chair. (You can do pretty well just lying on a blanket with a pillow, but you're more likely to fall asleep in that position and miss the best part of the show.) Tilt your head so you're looking slightly more than halfway up from the horizon to the zenith — the optimum direction for counting meteors. Take notes. And be sure you have a thermos of hot coffee, tea, or cocoa!\r\n\r\n[caption id=\"attachment_246758\" align=\"alignnone\" width=\"469\"]<img class=\"size-full wp-image-246758\" src=\"//coursofppt.com/wp-content/uploads/astronomy-meteor-viewing.jpg\" alt=\"astronomy-meteor-viewing\" width=\"469\" height=\"400\" /> Tilt your head halfway between the horizon and the zenith for optimum meteor viewing.[/caption]\r\n\r\nYou don't have to face the radiant when you observe a meteor shower, although many people do. The meteors streak all over the sky, and their visible paths may begin and end far from the radiant. But you can visually extrapolate the meteors' paths back in the direction from which they seem to come, and the paths point back to the radiant. Identifying a radiant in that way is how you can tell a shower meteor from a sporadic one.\r\n\r\nIf you do face the radiant, however, you see some meteors that seem to have very short paths, even though they appear fairly bright. The paths appear short because the meteors are coming almost right at you. Fortunately, the shower meteoroids are microscopic and won't make it to the ground.\r\n<p class=\"article-tips tip\">For more information on meteor showers, including historical events, facts, and advice on observing, head to the <a href=\"//skyandtelescope.org/\" target=\"_blank\" rel=\"noopener\">Sky and Telescope site</a> and enter \"Shooting Stars\" in the search window. Then you can download the free Shooting Stars e-book (you may have to register your email address).</p>","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}}],"primaryCategoryTaxonomy":{"categoryId":33758,"title":"Astronomy","slug":"astronomy","_links":{"self":"//dummies-api.coursofppt.com/v2/categories/33758"}},"secondaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"tertiaryCategoryTaxonomy":{"categoryId":0,"title":null,"slug":null,"_links":null},"trendingArticles":null,"inThisArticle":[],"relatedArticles":{"fromBook":[{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246753,"title":"Spotting Sporadic Meteors, Fireballs, and Bolides","slug":"spotting-sporadic-meteors-fireballs-bolides","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246753"}},{"articleId":246750,"title":"Planning Your First Steps into Astronomy","slug":"planning-first-steps-astronomy","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246750"}}],"fromCategory":[{"articleId":292167,"title":"The Magic of the Moon and the Total Lunar Eclipse","slug":"dont-miss-out-on-this-months-lunar-eclipse","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/292167"}},{"articleId":246769,"title":"Skywatching for Artificial Satellites","slug":"skywatching-artificial-satellites","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246769"}},{"articleId":246764,"title":"Making Heads and Tails of a Comet's Structure","slug":"making-heads-tails-comets-structure","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246764"}},{"articleId":246761,"title":"Photographing Meteors and Meteor Showers","slug":"photographing-meteors-meteor-showers","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246761"}},{"articleId":246753,"title":"Spotting Sporadic Meteors, Fireballs, and Bolides","slug":"spotting-sporadic-meteors-fireballs-bolides","categoryList":["academics-the-arts","science","astronomy"],"_links":{"self":"//dummies-api.coursofppt.com/v2/articles/246753"}}]},"hasRelatedBookFromSearch":false,"relatedBook":{"bookId":281963,"slug":"astronomy-for-dummies","isbn":"9781394163076","categoryList":["academics-the-arts","science","astronomy"],"amazon":{"default":"//www.amazon.com/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","ca":"//www.amazon.ca/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","indigo_ca":"//www.tkqlhce.com/click-9208661-13710633?url=//www.chapters.indigo.ca/en-ca/books/product/139416307X-item.html&cjsku=978111945484","gb":"//www.amazon.co.uk/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20","de":"//www.amazon.de/gp/product/139416307X/ref=as_li_tl?ie=UTF8&tag=wiley01-20"},"image":{"src":"//coursofppt.com/wp-content/uploads/astronomy-for-dummies-5th-edition-cover-9781394163076-202x255.jpg","width":202,"height":255},"title":"Astronomy For Dummies","testBankPinActivationLink":"//testbanks.wiley.com","bookOutOfPrint":true,"authorsInfo":"<p><p><b><b data-author-id=\"9879\">Stephen P. Maran</b>, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects.</p>","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/9879"}},{"authorId":35300,"name":"Richard T. Fienberg","slug":"richard-t-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. ","hasArticle":false,"_links":{"self":"//dummies-api.coursofppt.com/v2/authors/35300"}},{"authorId":35295,"name":"Richard Tresch Fienberg","slug":"richard-tresch-fienberg","description":" <p><b>Stephen P. Maran, PhD,</b> is the retired assistant director of space sciences for information and outreach at the NASA&#45;Goddard Space Flight Center. An investigator of stars, nebulae, and comets, he worked on the Hubble Space Telescope, Space Shuttle missions, Skylab, and other NASA projects. 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Start your study of astronomy by reviewing the accomplishments of the very first astronomers, and then continue looking at important historical markers of the Space Age.","description":"Astronomy is fascinating, and people have been looking at the stars since the dawn of humanity. Start your study of astronomy by reviewing the accomplishments of the very first astronomers, and then continue looking at important historical markers of the Space Age.","blurb":"","authors":[{"authorId":9879,"name":"Stephen P. Maran","slug":"stephen-p-maran","description":"<b>Stephen P. Maran</b>, PhD, is the retired assistant director of space sciences for information and outreach at the NASA-Goddard Space Flight Center. 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Start your study of astronomy, which encompasses literally everything in the universe, by reviewing a selection of notable accomplishments in astronomical history.</p>\n<ul>\n<li><strong>129 B.C.</strong> In Greece, Hipparchus completes the first known star catalog; it included more than 850 entries.</li>\n<li><strong>A.D. 150</strong> Claudius Ptolemy (who wrote in Greek but was of uncertain nationality) publishes his theory of the Earth-centered universe.</li>\n<li><strong>1420 </strong>Ulugh Beg, a ruler of Samarkand (now part of Uzbekistan), builds a great observatory and prepares tables of planet and star data.</li>\n<li><strong>1543</strong> Nikolaus Copernicus of Poland publishes his theory that planets — including Earth — orbit the Sun.</li>\n<li><strong>1572</strong> Tycho Brahe of Denmark observes a “new star” (now known to have been a supernova) in the constellation Cassiopeia. Five years later, he demonstrates that comets lie not in Earth’s atmosphere but far beyond the Moon.</li>\n<li><strong>1609</strong> Johannes Kepler of Germany, using Tycho Brahe’s unprecedentedly precise observations of planetary positions over many years, establishes that planets move not in circular orbits but in elliptical ones.</li>\n<li><strong>1610</strong> Galileo Galilei of Italy publishes his discoveries of the moons of Jupiter, the phases of Venus, craters and mountains on the Moon, and the presence of innumerable stars in the Milky Way made with a refractor (lens-based telescope) that he built himself after hearing about a “spyglass” invented in the Netherlands.</li>\n<li><strong>1668</strong> Isaac Newton in England builds the first astronomical reflector (mirror-based telescope), with a main mirror 2 inches in diameter.</li>\n<li><strong>1687</strong>  Newton publishes his laws of motion and theory of universal gravitation.</li>\n<li><strong>1781</strong> In England, William Herschel (originally from Germany) finds the planet Uranus — the first such discovery since prehistory — while sweeping the sky with a large reflector he built himself.</li>\n<li><strong>1838</strong> Friedrich Bessel of Germany first measures the distance to a star beyond the solar system, finding 61 Cygni to lie more than 10 light-years (60 trillion miles) away.</li>\n<li><strong>1839</strong> John W. Draper publishes the first photograph of the Moon. A year later, he helps take the first photo of a star (Vega, in the constellation Lyra).</li>\n<li><strong>1846</strong> Johann Galle and Heinrich d’Arrest in Germany discover the planet Neptune based on a prediction by Urbain Le Verrier in France.</li>\n<li><strong>1859</strong> In Germany, Gustaf Kirchhoff and Robert Bunsen invent the spectroscope, an instrument that enables scientists to determine the compositions of celestial objects solely from their light.</li>\n<li><strong>1901 </strong>Annie Jump Cannon publishes the first catalog of stellar spectra based on a classification method she devised at Harvard College Observatory.</li>\n<li><strong>1908 </strong>Cannon’s colleague Henrietta Swan Leavitt discovers the first accurate method for measuring great distances in space. George Ellery Hale at Mount Wilson Observatory discovers that sunspots are magnetic.</li>\n<li><strong>1915</strong> Albert Einstein introduces his general theory of relativity, describing gravity as the warping of space and time by massive objects.</li>\n<li><strong>1923</strong> Edwin P. Hubble shows that the Andromeda “nebula” is actually a galaxy like our own Milky Way and that the universe is far larger than anyone knew.</li>\n<li><strong>1925 </strong><strong>Cecilia Payne-Gaposchkin</strong> is the first to recognize that hydrogen is the most abundant chemical element in the stars and, by extension, the universe.</li>\n<li><strong>1929</strong> Hubble discovers that the universe is expanding; more distant galaxies recede from the Milky Way faster than more nearby ones.</li>\n<li><strong>1930</strong> Clyde Tombaugh, working at Lowell Observatory in Arizona, discovers Pluto, then called the ninth planet but now considered a dwarf planet and the brightest member of the Kuiper Belt of small icy bodies beyond Neptune.</li>\n<li><strong>1933</strong> Karl Jansky of Bell Telephone Laboratories in New Jersey announces the discovery of cosmic radio waves. Fritz Zwicky at Caltech proposes that clusters of galaxies contain dark matter whose gravity keeps the galaxies from escaping.</li>\n<li><strong>1938</strong> Hans Bethe of Cornell University shows that stars are powered by nuclear fusion at incredibly high pressures and temperatures.</li>\n<li><strong>1958</strong> Using the USA’s first satellite, Explorer 1, James Van Allen discovers Earth’s radiation belts (<em>magnetosphere</em>).</li>\n<li><strong>1959</strong> The Soviet Union’s Luna 3 probe is the first to photograph the Moon’s far side (the side that always faces away from Earth).</li>\n<li><strong>1960 </strong>Frank Drake begins the modern era of the search for extraterrestrial intelligence (SETI) at the National Radio Astronomy Observatory in Green Bank, West Virginia.</li>\n<li><strong>1962</strong> Riccardo Giacconi detects X-rays from beyond the Sun for the first time using an instrument aboard an Aerobee sounding rocket; the source, Sco X-1 in Scorpius, is a binary system containing a neutron star. NASA’s Mariner 2 becomes the first probe to successfully fly past another planet (Venus).</li>\n<li><strong>1965</strong> Arno Penzias and Robert W. Wilson discover the cosmic microwave background, the “echo” of the Big Bang, at Bell Telephone Laboratories.</li>\n<li><strong>1967</strong> Jocelyn Bell Burnell and Antony Hewish discover pulsars at the University of Cambridge. The Vela 3 and 4 satellites detect the first cosmic gamma-ray bursts.</li>\n<li><strong>1971</strong> Mariner 9 is the first spacecraft to orbit another planet (Mars). Richard Tousey of the U.S. Naval Research Laboratory discovers the Sun’s coronal mass ejections with the Orbiting Solar Observatory 7.</li>\n<li><strong>1973</strong> NASA’s Pioneers 10 and 11 are the first spacecraft to visit Jupiter (and later, Saturn).</li>\n<li><strong>1976</strong> Vikings 1 and 2 become the first spacecraft to land on Mars; E. Margaret Burbidge, a leading expert on galaxies and quasars, becomes the first female president of the American Astronomical Society.</li>\n<li><strong>1979</strong> Using pictures from Voyager 1, Linda Morabito at the Jet Propulsion Laboratory discovers erupting volcanoes on Jupiter’s moon Io.</li>\n<li><strong>1980</strong> Vera C. Rubin and Kent Ford of the Carnegie Institution investigate the rotation of galaxies and detect strong evidence of dark matter.</li>\n<li><strong>1984</strong> Astronauts of the Space Shuttle <em>Challenger</em> make the first repairs in space of an unmanned satellite, the Solar Maximum Mission.</li>\n<li><strong>1987 </strong>Canadian Ian Shelton and Chilean Oscar Duhalde discover Supernova 1987A, the first supernova since 1604 that was plainly visible to the naked eye, at Las Campanas Observatory, Chile.</li>\n<li><strong>1991</strong> Polish astronomer Alexander Wolszczan discovers planets orbiting a pulsar — the first known planets outside the solar system.</li>\n<li><strong>1992 </strong>Jane Luu and David C. Jewitt find Albion, the first object (other than Pluto and its large moon Charon) recognized to be orbiting the Sun in the Kuiper Belt beyond Neptune.</li>\n<li><strong>1994</strong> Multiple fragments of Comet Shoemaker-Levy 9, discovered a year earlier by Carolyn and Eugene Shoemaker and David H. Levy, crash into Jupiter, leaving scars visible in backyard telescopes.</li>\n<li><strong>1995</strong> Swiss astronomers Michel Mayor and Didier Queloz discover 51 Pegasi b, the first known planet orbiting a normal star beyond the Sun, from the Haute-Provence Observatory in France.</li>\n<li><strong>1998</strong> Two teams of astronomers independently discover that the expansion of the universe is getting faster, apparently due to a mysterious “dark energy” associated with the vacuum of space.</li>\n<li><strong>1999</strong> Mars Global Surveyor finds that the Red Planet may have had an ocean at one time.</li>\n<li><strong>2001</strong> A team led by Canadian-American astronomer Wendy Freedman of Carnegie Observatories publishes the most precise value of the Hubble constant (the cosmic expansion rate) to date based on observations from the Hubble Space Telescope.</li>\n<li><strong>2003 </strong>NASA’s<strong> </strong>Wilkinson Microwave Anisotropy Probe finds that the universe is 13.7 billion years old; later in the same decade, Europe’s Planck satellite refines this to 13.8 billion years.</li>\n<li><strong>2012</strong> The Kepler spacecraft finds that there probably are billions of planets in orbit around stars in our galaxy, and the rover Curiosity lands on Mars.</li>\n<li><strong>2013 </strong>The European Space Agency’s Gaia spacecraft is launched for observations to create a three-dimensional catalog of 1 billion stars.</li>\n<li><strong>2015 </strong>The New Horizons probe explores Pluto and its moons and then heads outward in the Kuiper Belt; a team of physicists detect gravitational waves for the first time using the Laser Interferometric Gravitational-wave Observatory (LIGO) in the U.S. states of Louisiana and Washington.</li>\n<li><strong>2019</strong> The globe-spanning Event Horizon Telescope captures the first image of a black hole, the supermassive object at the center of galaxy M87 in Virgo.</li>\n<li><strong>2020</strong> American Andrea Ghez and Germany’s Reinhard Genzel, whose teams independently proved the existence of a supermassive black hole at the center of the Milky Way galaxy, share the 2020 Nobel Prize in Physics.</li>\n<li><strong>2022</strong> NASA’s DART spacecraft slams into an asteroid to change its orbit to show how we might someday nudge an asteroid off of a collision course with our planet.</li>\n<li><strong>2023</strong> Early data from the James Webb Space Telescope suggest that large galaxies formed much earlier in cosmic history than current theory predicts.</li>\n</ul>\n"}],"videoInfo":{"videoId":null,"name":null,"accountId":null,"playerId":null,"thumbnailUrl":null,"description":null,"uploadDate":null}},"sponsorship":{"sponsorshipPage":false,"backgroundImage":{"src":null,"width":0,"height":0},"brandingLine":"","brandingLink":"","brandingLogo":{"src":null,"width":0,"height":0},"sponsorAd":"","sponsorEbookTitle":"","sponsorEbookLink":"","sponsorEbookImage":{"src":null,"width":0,"height":0}},"primaryLearningPath":"Advance","lifeExpectancy":"Five 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