S K Y SSS KKK YYY SSSSSSSSSSSSSSSSSSS KKKKKKKKKKKKKKKKKKK YYYYYYYYYYYYYYYYYYY GAZING GGGAAAZZZIIINNNGGG GGGGGGGGGGGGGGGGAAAAAAAAAAAAAAAAZZZZZZZZZZZZZZZZIIIIIIIIIIIIIIIINNNNNNNNNNNNNNNNGGGGGGGGGGGGGGGG A Guide to the MOON • SUN • PLANETS • STARS • ECLIPSES • CONSTELLATIONS Meg Thacher ß Storey Publishing 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 1 6/26/20 10:09 AM The mission of Storey Publishing is to serve our customers by publishing practical information that encourages personal independence in harmony with the environment. Edited by Deborah Burns Marcelo Quinan/Unsplash, 23 l.; Mars Vilaubi, 25 r., 49; Mbz1/ Text © 2020 by Margaret Glynn Lysaght Thacher CC BY-SA 3.0 Unported/Wikimedia Commons, 16 t.l.; © Meg Art direction and book design by Jessica Armstrong Thacher, 123 l.; Mike Kareh/Unsplash, 44; Morn/CC BY-SA 4.0 All rights reserved. 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Beletsky, 64 b.r.; © 2014 by Fred Espenak b.r., 79 b.c.r.; NASA’s Scientifi c Visualization Studio, 26, Description: North Adams, MA : Storey Publishing, [2020] | (MrEclipse.com), 38, 40; © GEOEYE/SCIENCE PHOTO 32–33, 36, 37, 41, 123 r.; Courtesy of NASA/SDO and the Includes bibliographical references and index. | Audience: LIBRARY, 68; Gregory H. 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Hervás, 63; J.P. Harrington and K.J. Borkowski (University Stock Photo, 65; Courtesy of Sebastian Saarloos, 23 b.r.; Classifi cation: LCC QB64 .T45 2020 (print) | LCC QB64 (ebook) of Maryland), and NASA/ESA, 117 l.; Jstuby at English © SellOnlineMarketing/iStock.com, 48; SOHO (ESA & | DDC 520—dc23 Wikipedia/CCo/Wikimedia, 34 l.; Kai Pilger/Unsplash, 88; NASA), 59 t.; Stephen Rahn/Wikimedia Commons, 117 LC record available at https://lccn.loc.gov/2020016777 © karinegenest/iStock.com, 16 t.r.; © Kazushi_Inagaki/ (Vega); Strebe/CC BY-SA 3.0 Unported/Wikimedia, 57; iStock.com, 28; Khongor Ganbold/Unsplash, 15; Klemen Image © Ted Stryk. Data Courtesy the Russian Academy LC ebook record available at https://lccn.loc.gov/2020016778 Vrankar/Unsplash, 6, op. 132; © ktasimarr/iStock.com, 18 t.l.; of Sciences, 70 b.r.; Visualization by Earth Observatory, 71 Lawrence Sromovsky, University of Wisconsin-Madison/ b.r.; © wisanuboonrawd/iStock.com, 115 t.; © www.capella- W.W. Keck Observatory, 78 b.c.l.; © Luis Argerich, 64 l.; observatory.com, 116 b.; © Yuri Beletsky, op. title page, 61 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 2 6/26/20 10:09 AM What's in This Book? With most books, you start at the beginning and read through to the gbuouSiopdtkt ea hn raio ynHnowDgiud! us a dsCtIneh hakda.rl nlro Itoe’umhwl gle s.ehnso hm tothewoi s Step in1 to the encialdnon.. s dTTe hshptiles a ( ctnbhheoaetops kMt) ewotrooasn s f)a a mrtreota h dofearesgr ttta oh(n tesihrzk eei( ptdsh tafearr rooSsmuu)n.n d SKY The Sky Belongs to Everyone. . . . . . . . . . . . . . . . . . . . . . .7 Light Shows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 What’s Up There? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 Special Effects. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 ASTRONOMY NOTEBOOK TRY IT: Watch Day Turn into Night . . . . . . . . . . . . . . . .18 Start a Sky Journal. . . . . . . . . . . . . . . . . . . . . . . . .8 Night Vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Where to Sky Gaze. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 TRY IT: Make a Red Flashlight . . . . . . . . . . . . . . . . . . .19 Darkness and Light. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Journey into Our Home Galaxy: Finding Your Way around the Sky. . . . . . . . . . . . . . . . . . .12 The Milky Way . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 TRY IT: Cosmic Protractor . . . . . . . . . . . . . . . . . . . . . . . . . .13 SPECIAL EVENT: The Aurora. . . . . . . . . . . . . . . . . . . . . . . .22 ASTRONOMY NOTEBOOK A CLOSER LOOK Be a Weather Watcher. . . . . . . . . . . . . . . . . . . . . . .14 Binoculars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 YYoouurr AAssttrroonnoommyy NNootteebbooookk wwiillll hheellpp 2 yyoouu kkeeeepp ttrraacckk ooff yyoouurr ddiissccoovveerriieess.. the MOON Shape-Shifter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 How the Moon Formed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 ASTRONOMY NOTEBOOK ASTRONOMY NOTEBOOK Make a Moon Diary. . . . . . . . . . . . . . . . . . . . . . . . . .28 Picture the Moon . . . . . . . . . . . . . . . . . . . . . . . . . . .36 Our One and Only Moon. . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 Moon Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 Moonrise, Moonset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 SPECIAL EVENT: Lunar Eclipse. . . . . . . . . . . . . . . . . . . . . .38 Moon Illusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 A CLOSER LOOK TRY IT: Do a Moondance . . . . . . . . . . . . . . . . . . . .31 The Moon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 Sightseeing on the Moon. . . . . . . . . . . . . . . . . . . . . . . . . . .32 Each chapter ends with a section called A Closer Look on how to observe the sky with binoculars. 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 3 6/26/20 10:09 AM 3 aSsrooemm eee aaasrcye t. iv hiFta ioraeldlnsoe dwr SUtheN the stars! Sunwise. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 A Visit to the Sun. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 How the Sun Formed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 ASTRONOMY NOTEBOOK Make a Sunset Calendar. . . . . . . . . . . . . . . . . . . . .44 SPECIAL EVENT: Solar Eclipse . . . . . . . . . . . . . . . . . . . . . .54 How Seasons Happen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 TRY IT: Make a Pinhole Projector . . . . . . . . . . . . . . .58 Sun Paths. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 A CLOSER LOOK Telling Time by the Sun. . . . . . . . . . . . . . . . . . . . . . . . . . . .48 Our Sun. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59 TRY IT: Track the Sun . . . . . . . . . . . . . . . . . . . . . . . . . . .49 4 PLANETS Earth’s Siblings in the Sky . . . . . . . . . . . . . . . . . . . . . . . . .61 ASTRONOMY NOTEBOOK Star or Planet?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62 Design Your Own Solar System . . . . . . . . . . . . . . .77 Planets Inside and Outside. . . . . . . . . . . . . . . . . . . . . . . . .64 TRY IT: Be the Solar System . . . . . . . . . . . . . . . . .81 Sky Wanderer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65 How the Solar System Formed. . . . . . . . . . . . . . . . . . . . . .82 Roaming around the Solar System. . . . . . . . . . . . . . . . . .66 SPECIAL EVENT: Great Comet. . . . . . . . . . . . . . . . . . . . . . .84 TRY IT: Make a Scale Model . . . . . . . . . . . . . . . . . . . .68 Other Suns and Their Solar Systems. . . . . . . . . . . . . . . .86 Meet a Planet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69 A CLOSER LOOK MERCURY . . . . . . . . . . 69 SATURN. . . . . . . . . . . . 76 The Planets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .87 VENUS. . . . . . . . . . . . . 70 URANUS . . . . . . . . . . . 78 EARTH. . . . . . . . . . . . . 71 NEPTUNE . . . . . . . . . . 79 MARS. . . . . . . . . . . . . . 72 PLUTO and other JUPITER . . . . . . . . . . . 74 Dwarf Planets. . . . 80 You’ll also find instructions for viewing Special Events like eclipses and meteor showers. 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 4 6/26/20 10:09 AM 5 If you want actwoona sys,tt eaylorlautt ’illole nafsri nnrdiing ghs kt y SSTTAARRSS maps here. and CCOONNSSTTEELLLLAATTIIOONNSS Star Light, Star Bright. . . . . . . . . . . . . . . . . . . . . . . . . . . . .89 Star Seasons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 How Stars Move During the Night. . . . . . . . . . . . . . . . . . .90 TRY IT: Make Your Own Star Wheel . . . . . . . . . . . . . .98 TRY IT: Find North & South Using the Stars . . . . . . . .94 Seasonal Sky Gazing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 Why Humans Invented Constellations. . . . . . . . . . . . . . .95 How Stars Are Born, Live, and Die. . . . . . . . . . . . . . . . . . .112 ASTRONOMY NOTEBOOK SPECIAL EVENT: Meteor Shower. . . . . . . . . . . . . . . . . . . . .114 DIY Constellations. . . . . . . . . . . . . . . . . . . . . . . . . .95 A CLOSER LOOK The Zodiac and the Ecliptic. . . . . . . . . . . . . . . . . . . . . . . .96 Deep Sky Objects. . . . . . . . . . . . . . . . . . . . . . . . . .116 APPENDIX: Find Out More TRY IT: Throw a Star Party . . . . . . . . . . . . . . . . . . . .119 Glossary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .126 Meteor Shower Calendar . . . . . . . . . . . . . . . . . . . . . . . . . . .119 The glossary has definitions of words you may not know — and words that astronomers use in a different Eclipses 2020–2030 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120 way from most people. (In the book those words are highlighted, like this, when first used.) Binocular Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Buying Binoculars. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128 TRY IT: Make Dew Shields . . . . . . . . . . . . . . . . . . .123 Resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 Imagine that the tpthlhaiisns ie fbstp oo ayolbgoakueer. , soIcfwynas ,hntt a ehatfemp i pnp rSdacou goxtneuihm ledcwa mootfuue iltalldyd l ?l i!fn e i Sta ecoehn (Answers on page 131.) Sun 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 5 6/26/20 10:09 AM 1 Step into the SSSSkkkkyyyy SSSkkkyyy SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy Our universe is fi lled with stars, planets, and all sorts of amazing stuff  — and you can see them no matter where you live. You don’t need fancy tools: just look up. 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 6 6/26/20 1:37 PM The Sky Belongs wVeaintuLinosog k hsfa osLr ibkueese !n to Everyone Long ago, kids knew all about the space. Astronomy is interesting night sky. Th ey could fi nd north for its own sake, but it’s also an and tell time by the Sun. Th ey important part of human history. knew which constellations came Ever since there were people, with which season. we’ve been looking at the stars : Of course, this was easier tracking and recording their before the invention of street- motion, making pictures and sto- lights. Th e sky they saw was ries out of them, and wondering SKY-GAZING speckled with thousands of stars. why they are there. SUPPLIES Th ese days, we can see only a few Th e sky inspired us to invent hundred from our cities and sub- math and physics so we could urbs. Many people live their whole explain what caused nature’s pat- If you want to watch a meteor shower or have life without seeing the Milky Way. terns, starting with how objects a sky-gazing party, pack some extra stuff to keep yourself comfortable outside at night. But no matter where you live move across the sky. It got us think- or how many stars you can see at ing about more than just what to eat You might want to bring: night, you can observe the sky. and where to live; it showed us our (cid:31) water and a snack You can do everything those kids place in the universe. (cid:31) a sky map or Star Wheel (see chapter 5) from long ago could do — and (cid:31) a blanket more! We’ve learned a lot about You can observe the night (cid:31) a red flashlight (see page 19) the universe since our ancestors sky anytime, anywhere — (cid:31) a regular flashlight started sky gazing. for free! Start a habit of Th is book is about astronomy, looking up at stars whenever you (cid:31) bug repellent the study of stars, planets, and step outside at night. (cid:31) a pencil (cid:31) your Astronomy Notebook (see page 8) Or you can just step out onto your fire escape or porch and look up! For more tips on throwing a star party, see page 119. Part of the Egyptian zodiac from the Temple of Hathor in Dendara, Egypt, built around 50 BCE. It was sculpted and painted onto the temple’s ceiling. The body of Nut, the goddess of the sky, lies along the bottom. STEP INTO THE SKY 7 Mercury 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 7 6/26/20 1:38 PM ASTRONOMY NOTEBOOK Start A Sky Journal When you sky gaze, it’s fun to draw what you see in the sky and take notes. AAAnnn AAAssstttrrrooonnnooommmyyy NNNooottteeebbbooooookkk wwwiiillllll kkkeeeeeeppp aaallllll ooofff yyyooouuurrr ooobbbssseeerrrvvvaaatttiiiooonnnsss ttooggeetthheerr.. YYoouu ccaann bbuuyy aa nneeww nnootteebbooookk oorr uussee aann oolldd oonnee that still has some blank ppaaggeess lleefftt.. RRiipp oouutt yy oouurr oolldd sscchhoooollwwoorrkk,, aanndd ddeeccoorraattee the front. Use your Astronomy Notebook to record the weather, draw pictures of What‘s Up There? the sky, and keep track of your research. When you record an observation you should include the following information: No matter how dark or light your dark enough, you may see a faint sky is, you can always observe the trace of the MilkyWay, the galaxy ➔ Date Sun and Moon! And even from we live in. (A galaxy is a huge star a lit-up place like a city or large system containing gas, dust, and ➔ Tim e suburb, you can see the bright- hundreds of billions of stars .) ➔ Weather est planets, stars, and meteors If you have the chance to visit (fl ashes of light caused by bits of a place that is very dark at night, ➔ How clear is the sky? rock from outer space entering like a national park, you will see the Earth’s atmosphere), and the Milky Way clearly, with its ➔ Can you see the Moon? even the International Space many stars and dust lanes. Star Where is it and what shape? Station. clusters, nebulae (clouds of gas From a darkish place outside and dust), and even galaxies may ➔ What else can you see? the suburbs, you can see most be visible as well. ➔ What's different from the of the constellations (groups last time you looked? of stars that look like a picture). The word nebula comes Space from the Latin word for You can also see meteors and Talk cloud. One is a nebula; human-made satellites. If it’s two or more are nebulae. 8 STEP INTO THE SKY Venus 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 8 6/26/20 10:09 AM Where to Sky Gaze Good places to look at the stars and east from a friend’s house. include a backyard, a balcony, a Observing from a hill or rooftop safe rooftop that you’re allowed to can get you a better view. go out on, a playing fi eld, or a park. In modern times, we have Try to fi nd a place with a clear many lights inside and outside horizon — that is, where nothing our homes. Th ey help us see at blocks your view. Maybe you can night, but they can cause light see the southern and western sky pollution (artifi cial light that The constellations of Sagittarius and Scorpius, as seen from a city from where you live, and the north makes the sky bright). (population 400,000) and a small town (population 217). Too Much Light POINT-SOURCE light pollution comes from one place. You can If the sky is brighter than a partic- move to get away from it. If a ular star, we can’t see that star. So nearby streetlight is making it in places with a lot of light pollu- hard to see the stars, for example, tion, we can see only really bright you can move so that a building stars and planets. blocks it from your view, or you DIFFUSElight pollution lights up can hang a blanket from a clothes- the whole sky. You can’t get away line to block it out. Even just A handy way to block point-source light pollution from it unless you go somewhere blocking the light with your hand with less light. will improve what you see! Best Timing Once you’ve found a good place Å TIMING. You’ll have to wait until Å PLANETS. Often you may see Å SPECIAL EVENTS. Eclipses, to observe the night sky, keep the twilight — the time right after a planet that is brighter than meteor showers, comets, the following things in mind. sunset or before sunrise when most stars. Look online or in an northern lights — there’s always the sky is not bright but still astronomy magazine to learn something interesting going Å WEATHER. You can observe softly glows. Then it will be dark what planets will appear in the on in the sky! Special events the Moon and planets through enough to observe most stars. sky and when. Over several are found in every chapter of a partly cloudy sky. To see months you can watch planets this book, and many are listed in constellations well, you need an Å MOON. Check the Moon’s phase change positions as if they're in a the Appendix, “Find Out More.” almost clear sky. (that is, how much of the Moon big dance. (See Chapter 4.) Be sure to dress appropriately. is visible from Earth; see page Weather is hard to predict, 27) and its rise and set times. If so check the sky and the it’s a very bright Full Moon, it will temperature before you head out outshine fainter objects in the to make your observations! sky and you won’t be able to see them. (Observe the Moon instead!) STEP INTO THE SKY 9 Earth 626096_SkyGazing-FINAL_Signoff_Pgs_Part1.indd 9 6/26/20 10:09 AM