Big Book of Knowledge

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FIRST EDITION 1994 THIS EDITION 2019 General Editor Sarah Phillips Produced for DK by General Art Editors Ruth Shane, Paul Wilkinson Dynamo Limited Subject Editors Francesca Baines, Val Burton, Second Floor, Exeter Bank Chambers, 67 High Deborah Chancellor, Roz Fishel, Hilary Hockman, Street, Exeter EX4 3DT Rosemary McCormick, Sarah Miller, Seán O’Connell, Project Editor Ben Ffrancon Davies Jean Rustean, Anne de Verteuil US Editor Karyn Gerhard Subject Art Editors Flora Awolaja, Liz Black, Amanda Carroll, Richard Clemson, Ross George, Subject Consultants Peter Chrisp, Penny Johnson, Susan Pattie, Kristina Routh, Sarah Goodwin, Sara Nunan, Ron Stobbart, Andrew Walker, Sonia Whillock Chris Woodford, John Woodward Jacket Editor Emma Dawson Designers Wayne Blades, Alison Greenhalgh, Jacket Designer Prarthana Dixit, James Hunter, Marianne Markham, Tuong Nguyen, Surabhi Wadhwa-Gandhi Alison Verity, Samantha Webb DTP Designer Rakesh Kumar Picture Researchers Lorna Ainger, Jackets Editorial Coordinator Priyanka Sharma Caroline Brook, Venetia Bullen, Anna Lord, Managing Jackets Editor Saloni Singh Jacket Design Development Manager Miriam Sharland, Paul Snelgrove Subject Consultants Dr Michael Benton, Nicholas Booth, Sophia MTT Producer, Pre-production Robert Dunn Martyn Bramwell, Roger Bridgman, Eryl Davies, Liza Dibble, John Farndon, Adrian Gilbert, Alan Harris, Producer Meskerem Berhane Paul Hillyard, Dr Malcolm MacGarvin, Diana Maine, Managing Editor Lisa Gillespie Managing Art Editor Owen Peyton Jones Margaret Mulvihill, Dr Fiona Payne, Chris Pellant, Dr Richard Walker, Shane Winser Publisher Andrew Macintyre Production Manager Ian Paton Associate Publishing Director Liz Wheeler Production Assistant Harriet Maxwell Art Director Karen Self Editorial Director Jonathan Reed Publishing Director Johnathan Metcalf Design Director Ed Day This American Edition, 2019 Published in Great Britain by Dorling Kindersley Limited First American Edition, 2002 A catalog record for this book is available from the Library of Congress. Published in the United States by DK Publishing 1450 Broadway, 8th Floor, NewYork, NY 10018 ISBN: 978-1-4654-8041-5 Copyright © 2002, 2019 Dorling Kindersley Limited DK books are available at special discounts when purchased DK, a Division of Penguin Random House LLC in bulk for sales promotions, premiums, fund-raising, or educational use. 19 20 21 22 23 10 9 8 7 6 5 3 4 2 1 001–312776–Mar/2019 For details, contact: DK Publishing Special Markets, 1450 Broadway, 8th Floor, NewYork, NY 10018 All rights reserved. [email protected] Without limiting the rights under the copyright reserved above, no part Printed and bound in Malaysia of this publication may be reproduced, stored in or introduced into A WORLD OF IDEAS: a retrieval system, or transmitted, in any form, or by any means SEE ALL THERE IS TO KNOW (electronic, mechanical, photocopying, recording, or otherwise), without the prior written permission of the copyright owner. www.dk.com ACKNOWLEDGMENTS Photographers: Peter Anderson, Steve Bartholomew, Peter Chadwick, Tina Chambers, Andy Crawford, Colour Company, Geoff Dann, John Downes, Michael Dunning, John Edwards, Lynton Gardiner, Steve Gorton, Colin Keates, Tim Kelly, Gary Kevin, Chris King, Dave King, Cyril Laubscher, Kevin Mallett, Ray Moller, David Murray, Tim Ridley, David Rudkin, Karl Shone, James Stevenson, John Swift, Harry Taylor, Andreas von Einsiedel, JerryYoung. Illustrators: Graham Allen, Norman Barber, David Bergen, Roby Braun, Peter Bull, Joanna Cameron, Jim Channell, Bob Corley, Sandra Doyle, David Fathers, Roy Flooks, Tony Gibbons, Mike Gillah, Tony Graham, Peter Griffiths, Terry Hadler, Edwina Hannah, Charlotter Hard, Kaye Hodges, Keith Hume, Ray Hutchins, Aziz Khan, Pavel Kostal, Norman Lacey, Stuart Lafford, Kenneth Lilly, Linden Artists, Steve Lings, Mike Loates, Chris Lyon, Alan Male, Richard Manning, Janos Marffy, Josephine Martin, Annabel Milne, Sean Milne, Patrick Mulray, Richard Orr, Alex Pang, Darren Pattenden, Liz Pepperell, Jane Pickering, Gill Platt, Maurice Pledger, Sebastian Quigley, Christine Robins, Eric Rome, Michelle Ross, Simon Roulstone, Colin Salmon, John Searl, Pete Serjeant, Rob Shone, Clive Spong, Roger Stewart, John Temperton Grose Thurston, Graham Turner, Brian Watson, Phil Weare, Sonia Whillock, John Woodcock, Michael Woods. Models: Celia Allen, Roby Braun, Atlas Models, Cheltenham Cutaway Exhibits Ltd, Crystal Palace Park, London, Arril Johnson, Donks Models, Centaur Studios, Norrie Carr Model Agency, Peter Giffiths, John Holmes, Scallywags Model Agency, Truly Scrumptious Child Model Agency.

Big Book of Knowledge

Contents Insects and Spiders 108 Chapter 1 earth and SpaCe 8 Earth 10 Dinosaurs 132 Space 34 Birds 152 Chapter 2 the natural World 56 Plant Life 58 Mammals 186 Sea Life 84 The Human Body 218

Chapter 3 Chapter 4 Our WOrld 248 SCienCe and teChnOlOgy 392 People in the Science Past 250 and Arts and Machines Entertainment 394 294 Food and Energy and Industry 428 Farming 320 Transportation 452 People and Places 348 Index 474

HOW TO USE THIS BOOK It’s easy to use the Big Book of Knowledge. Start by looking at the contents page. There you will see that the book has four chapters, which are divided into different subject areas. Find a subject or a picture that interests you, and turn to that page. If you can’t find what you want on the contents page, look it up in the index at the back. This is an alphabetical list of everything covered in the book. After each entry, there is a list of all the pages on which that topic is mentioned. See how the index works by looking up “butterflies.” Turn to all the pages listed after BUTTERFLIES the entry until you find the main page for Butterf lies are perhaps the most beautiful of all Butterflies shown here. insects. It is amazing to think that a fat, leaf-eating caterpillar can become a brightly colored, fluttering This page uses a picture of that section to creature of the air. The change happens in the tell you about some of the regular features butterf ly chrysalis. The caterpillar’s body is broken you will find in the Big Book of Knowledge. down and completely changed. After about four weeks, a fully formed butterf ly emerges. Time to wake up 1. No longer a caterpillar, The butterfly comes a beautiful butterfly out of the chrysalis in comes out of the three stages. During chrysalis with this time it is very its wings open to attack crumpled up. by hungry birds or spiders. Title and Introduction BUTTERFLIES Happy landings In the background Each double page deals A clouded yellow butterfly comes Some butterflies make a tasty meal fo with a different subject. Butterf lies are perhaps the most beautiful of all in to land on a thistle. Butterfly birds. But if they are able to blend in The title tells you exactly insects. It is amazing to think that a fat, leaf-eating flight is more controlled than it their background, they may avoid bei what the subject is, and caterpillar can become a brightly colored, fluttering looks. The insect is able to eaten. The open wings of the Indian l the introduction gives creature of the air. The change happens in the change course instantly and butterfly have a strikin you some basic butterf ly chrysalis. The caterpillar’s body is broken make sudden landings. orange pattern. But down and completely changed. After about four when its wings are clos weeks, a fully formed butterf ly emerges. ccBaouilllteetdderuaflpipeMswroMfhlBoebieenvouondseatsc,tntriwhsaocb.rhntThouediushtnntgidoeshuwrinisefiaselnti.itehtnueserboaemcnroeeombpveoelasrcne,. the butterfly looks exac like an old, dry leaf. to the eaBsutettrenrfalinesd western coasts ofhNavoertchluAbbmederica, information about it. Time to wake up 1. No longer a caterpillar, thousandsanotfenmnoanea. rchs Wings closed, The butterfly comes a beautiful butterfly fly south to the warmth of Wings open. resting on leaf. comes out of the out of the chrysalis in chrysalis with California and Mexico. When w2.aTrmhe wbuetattehrfelry rmetuusrtnsstatyo their 3.When its wings have BUTTERFLIES three stages. During HA acplopuydeladnydceirlnluogwmsitpbsluewtdtienurfgplsy. comes fsitrislltfhoromaen, ythheoyufrlsy, ansobrltohodagain. hardened, the butterfly this time it is very in to land on a thistle. Butterfly is pumped into the wing veins is ready to fly off to find open to attack flight is more controlled than it In the background to stretch the wings. Later it by hungry looks. The insect is able to Some butterflies make a tasty meal for holds its wings apart to its first meal of nectar. birds. But if they are able to blend in with let them harden. birds or their background, they may avoid being 116 spiders. eaten. The open wings of the Indian leaf Butterf lies are perhaps the most beautiful of all W insects. It is amazing to think that a fat, leaf-eating change course instantly and butterfly have a striking make sudden landings. orange pattern. But caterpillar can become a brightly colored, fluttering when its wings are closed, creature of the air. The change happens in the Butterflies feed through a tube butterf ly chrysalis. The caterpillar’s body is broken called a proboscis.This is Captionsthe butterfly looks exactly down and completely changed. After about four coiled up when not in use. weeks, a fully formed butterf ly emerges. like an old, dry leaf. Butterflies have clubbed Most double pages antennae. Wings closed, featureBrilliant one large, exciting Time to wake up 1. No longer a caterpillar, resting on leaf. butterflies G The butterfly comes a beautiful butterfly Wings open. out of the chrysalis in comes out of the 2.The butterfly must stay 3.When its wings have picture. All around it, three stages. During chrysalis with still for many hours, as blood hardened, the butterfly this time it is very its wings is pumped into the wing veins is ready to fly off to find open to attack crumpled up. Monarchs ontotshtreetcmh othveewings. Later it its first meal of nectar. captions point out by hungry birds or Most abnudttderihlefelotiiletdnhsseoimatnsrheewaibprndogleasrncna.ep,.art to important details. TheyWallace’s golden birdwing spiders. live, But when winter comes Scaly wings to the eastern and western coasts of North America, will help you to look The wings of both butterflies thousands of monarchs and moths are covered with fly south to the warmth of carefully at the picturetiny scales, which overlap like California and Mexico. When the tiles on a roof. Bright warm weather returns to their colors can either be used to first home, they fly north again. and understand it.Glass swallowtail butterfly attract a mate, or to warn predators that the butterfly, or moth, is not good to eat. Cram 116 117 Scaly wings Monarchs on the move The wings of both butterflies 88 butterfly Most butterflies are born, and moths are covered with live, and die in one place. tiny scales, which overlap like But when winter comes the tiles on a roof. Bright to the eastern and western coasts of North America, thousands of monarchs fly south to the warmth of

BUTTERFLIESMeasurements In most cases, units of measurement are spelHleapdpy landings In the background out, but in some places you will come across theA clouded yellow butterfly comes Some butterflies make a tasty meal for in to land on a thistle. Butterfly birds. But if they are able to blend in with flight is more controlled than it their background, they may avoid being s are perhapfos tlhloe wmoinstgbeaabutbifruel ovfiaaltlions. looks. The insect is able to eaten. The open wings of the Indian leaf change course instantly and is amazing to think that a fat, leaf-eating make sudden landings. butterfly have a striking orange pattern. But r can becomcema brightl=y colocreedn, ftliumtteertinegrs Butterflies feed through a tube when its wings are closed, ocfchotrhmyespaallieirst..eTTlymkhhceemhccahantagenergpdei.lAlh==aafrtp’esprbeaonmkbdsoiyliuenoittsmtfehobrueresortkeenrs called a proboscis.This is the butterfly looks exactly coiled up when not in use. like an old, dry leaf. ully formed kbumtte/hrfly em=ergesk. ilometers per hour Butterflies have clubbed e up l = liters1. No longer a caterpillar, antennae. Wings closed, Brilliant comes a beautiful butterfly resting on leaf. butterflies ysalis in comes out of the Wings open. During chrysalis with Wallace’s golden birdwing very its wings Stories in a Box2.The butterfly must stay k crumpled up. still for many hours, as blood Amazing facts or stories appear in a box.is pumped into the wing veins to stretch the wings. Later it Sometimes boxes suggest experimentsholds its wings apart to to try, or things to do that will help youlet them harden. 3.When its wings have hardened, the butterfly is ready to fly off to find its first meal of nectar. Happy landings In the background understand the subject better. A clouded yellow butterfly comes Some butterflies make a tasty meal for in to land on a thistle. Butterfly birds. But if they are able to blend in with flight is more controlled than it their background, they may avoid being lanclohdoaknisgn.eTgchoseuirnsseecintsitsaanbtllye to eatIenn. Tthheeopbenabuwcttiknerggfslryoohf uathvnee aIdnsdtriaikninlegaf Happy and A cloudedmyaekellsouwddebnulatntdeirnfglsy. comes Some buotrtaengreflpiaetstermn. aBkute a tasty meal for birds. Butwhtheeibnfuittttshewrefilynyglasooarkrees cealxobascletedly,to blend in with in to land on a thistle. Butterfly Picture Catalogsflight is mocBrauelltetcderoaflinpesrtofreboeodslcltihes.rdTouhgtishhiaas ntubiet ERFLIES On some pages, youlooks.The cionilsedecupt wisheanbnolteintouse. their baclikkge ranouoldn,ddr,ytlheaef.y omf atyheAHavIaconploidpduiyadbneleadilnneyadgefilnlogws In the background Glass swallowtail butterfly eaten. The open wings butterfly comes Some butterflies make a tasty meal for change course instantlyBaunttderflies butterfly haveinatostlraiknidnogn a thistle. Butterfly birds. But if they are able to blend in with Wings colnosleedawo,f.rhaenngeitspwatitnegrflbnsolBui.ogarttihBkrellerstiufa.licniTtseltsohmseeoidrne,sceoctnitsroalblelde than it their background, they may avoid being ftbpwioeigicltutltwhurfeeeirneeoldnsaurtattghhetraehotomewna.dreoei.ffTfsesirmmryeiantlolaclresgenmikelrgygpdohtei.hestlmAlltahmyawtCaccBbfreaoaatcap’auerkrilefslmlloilgteapeeyfrtMoftddebeluswsheraMcrooualBtosnoueoafoitonutlnvudiar.uaobpiiat,edtptsasetfseshdhh,taotasrwruwlsyeedenatncobeioufrhonnhdhldebeun,efardesteailisht2stoteesnohtolMNndsos.tftifsoatdTopleeltstfultdcwff-teounlhrinhetnrhfsiowbrermfoureeheimexsdnlinnmotrtatat.ipbiciuerrhssheaitctmtohnTrueoanlehwsodomettntAratiltnrauBhatoohh.gineeaniarnikmtdmnercWnagndyirsrhufgtntroswleehce.huvosteywehnotmhoehiiearoigettsb.npmvnahenhaenfisuspieegeconasrelencuarrns.astvatsr.gtrlwsfee,ce,ttnuLaunlarieictsnan,esbnbolet.tguaa.bebseebyrlv.oebeioeditddnsrestingtoeaten. The open wings of the Indian leaf first home, they fly north again. Wings open. o longer a ca2t.eTrphiellabru,tterfly must stay the butterfly lcohoaknsgexcaocutlryse instantly and butterfly have a striking a becaoumtiefus lsiostbuiupltltuotfefmorrtfphlmyedaninytohothuersw, ain1s1gb6lvoeoidns3.When its wings have like an old, drmyalkeeafs.udden landings. orange pattern. But 88 butterfly chrystaolsistrweticth the wings. Later it hardened, the butterfly hiotsldwsinitgsswings apart to is ready to fly off to find Scaly wingswhen its wings are closed, crumlept ltehdemup.harden. its first meal of nectar. Butterflies feed through a tube The wings ofthbeotbhubtutettrefrlfylielos oks exactly and moths awrlhiekiccehoavoenvreeordlladwp,itldhikrey leaf. Wallace’scgaollldeedn abirpdrwoinbgoscis.This is tiny scales, Wings closed, coiled up when noBt rinilluisaen. t resting on leaf. butBteurttfelrifelises the tiles on a roof. Bright colors can either be used to attract a mate, or to warn Wings open. have clubbed predators tWhaitntghsecbloustetedr,fly, Cramer’s bblBuuertmtiellorirfaplniheotsbutterfly 3.When its wings have antennae. or moth, isrensotitnggooodn tloeaefa.t. hardened, the butterfly Glass swallowtail butterfly Wings open. 117 is ready to fly off to find 2.The butterfly must stay 3.When its wings have its first meal of nectar. still for many hours, as blood hardened, the butterfly is pumped into the wing veins is ready to fly off to find 88 buthttoeorlfsldtyrsWeittcashlwltahicneegw’ssiagnpogasld.rtLetnaotebriridt wing its first meal of nectar. Scaly wings let them harden. The wings of both butterflies Wallace’s golden birdwing and moths are covered with tiny scales, which overlap like the tiles on a roof. Bright colors can either be used to attract a mate, or to warn predators that the butterfly, or moth, is not good to eat. Cramer’s blue morpho butterfly 117 Glass swallowtail butterfly Glass swallowtail butterfly on the move Close-8u8pbustterfly 88 butterfly erflies are born, Scaly wings Occasionally, you will find Cramer’s blue morpho butterfly die in one place. The wings of both butterflies an image that showSTschayelowy iwunginsgosf both butterflies winter comes and moths are covered with something in fmororinestatdihntneadyetnmsitlceaoacsltieeholsns.,, awarheroiccohofv.oeBvreerirdglahwptitlhike tern and western tiny scales, which overlap like This picture, bcauottltroatrcset craafmnlyeait’tehs, eorrbteo used to North America, the tiles on a roof. Bright shows you what a warn of monarchs colors can either be used to wCrianmger’sloblouekmsolripkhoebuutpterfclopylrroemdsaoettoh!r,sisthnaotttghoeobduttoteerfalty., e warmth of attract a mate, or to warn Mexico. When predators that the butterfly, 117 turns to their or moth, is not good to eat. fly north again. 117 116 7



chapter 1 ANEDASRPTAHCE To us, our planet Earth seems enormous, but if we were able to gaze at it across the vastness of space, it would look like a tiny speck. It is one of the eight planets that are constantly hurtling around a star— our sun—along individual elliptical paths called orbits. Together, the sun and its planets are known as the solar system. This, in turn, is part of a cluster of millions of stars and planets, called a galaxy. Our galaxy, which is shaped like a spiral, is called the Milky Way. It is so huge that a jet would take more than 100 billion years to fly across it. Scientists think that there are at least 200 billion different galaxies in our universe. Stars are made from layers of burning gas around a dense core. Some planets are also mostly gas, but other planets and moons are rocky, like Earth. Earth Space

EARTH Imagine you are an astronaut looking at Earth from your spacecraft. What you see is a big blue ball covered with swirling clouds that hide features such as continents and mountains. The ball looks so blue because more than two-thirds of it is covered with water in the form of oceans, seas, lakes and rivers. The surface of Earth, called the crust, moves all the time, but this movement is so slow that we are not aware of it. Eventually, however, pressure builds up and causes earthquakes. Changes also happen when the crust is worn away by water or huge blocks of moving ice called glaciers, or when volcanoes erupt. Our planet can support life only because it gets light and heat from the sun. Without it, the Earth would be a cold, dark and dead place. The Himalaya mountains in Nepal look very different from far out in space. 10

Stalactites form in caves. Sandstone Pumice Green marble Uluru in Australia is made of sandstone. Earth photographed from a satellite

ECARRTUHS’TS The crust is a thin layer of rock between Just like you, Earth has a very 3.7 and 43.5 miles (6 and 70 kilometers) thick. The mantle is the layer below the crust. Parts of it are molten where volcanoes form. thin skin. It is so thin that if you compare it to the whole Earth, it is thinner than the skin of an apple.   Earth’s skin, or crust, is made up of rock, built The outer core up in layers over millions is made of iron of years. The layers look and nickel that like blankets on a bed, have melted to form a liquid. with lots of lumps The inner core is a ball of and bumps in them. iron and nickel. It is hotter here than at the outer core, but the ball stays solid. How mountains are made Overfold Many mountains are made when the Earth’s crust is pushed up Downfold in big folds or forced up or down in blocks. The different shapes made are given different names. Upfold

The sea lies on top of the The land is made out of oceanic crust. Some of it is the continental crust. It is found underneath the edge thickest where mountains of the continental crust. are found. Under the oceans the crust The mantle Going down is as little as 3.7 miles (six This is a rift valley. It was made kilometers) thick, but under when a block of land sank down the continents it is up to between two long breaks, called 43.5 miles (70 kilometers) thick. faults, in the Earth’s crust. Block mountain Fault Rift valley A long way to go Going up Did you know that the deepest hole ever Here the land has been pushed into drilled into Earth’s crust is only 7.5 miles giant folds by movements in the Earth’s (12 kilometers) deep? To reach the center of the crust.You can see how the crust is Earth, you would have to drill 500 times deeper. made up of lots and lots of layers of rock. 13

MOPVILNAGTES All scrunched up The Earth’s surface is not Sometimes, two plates one unbroken piece. It is push against each other made up of many pieces that and then crumple the fit together like a giant jigsaw puzzle. land to make huge These pieces, called plates, move as mountain ranges. the mantle slowly moves beneath them. Going down The movement of the plates can cause Sometimes, one plate spectacular effects—earthquakes split slides under another. the crust, volcanoes form, new land is It is pushed down into made, and huge mountain ranges are the mantle and melts. pushed skyward. Doing the splits On the move The red dots show Sometimes, two plates The plates are never you the places where split apart and lava still, they are always earthquakes happen. bubbles up to fill the moving. In one year gap. It hardens and they can move about makes new land. 1 inch (2.5 centimeters), Slip sliding away about as much as your Sometimes, two plates fingernails grow in the slip past each other. same amount of time. This is another kind of movement that causes earthquakes. Continent

Past, present, future 0 MILLION YEARS Changing places Have you ever wondered what The land is coming together Earth looked like in the past? to make one gigantic continent. These pictures show you how the 30 O continents have moved over the PANGAEAGO last 300 million years, and how 250 MILLION YEARS AG All together the world may look 50 million A The supercontinent years from now. has come together. It is called Pangaea. Worlds apart 200 MILLION YEARS AGO The land is LAURASIA drifting apart GONDWANALAND again. Pangaea is splitting into two, Laurasia and Gondwanaland. The restless Earth TODAY This spot in Iceland is where two plates are moving apart, forming new land in the gap. Familiar ground Today, the world These lines show looks like this, but where two plates meet. the continents are still moving. 50 MILLION YEARS’ TIME Looking Ahead This is how the world may look in 50 million years. Can you spot how the land has changed its shape? To start you off, find Africa on the globe and see how it has joined up with Europe. 15

VOLCANOES When you shake up a can of soda pop and open it, the contents shoot out with a great whoosh! Some volcanoes act a bit like this. With tremendous force, Volcanoes can be quiet and not erupt for a long time. molten (melted) rock bursts through weak parts in the Earth’s crust and is hurled high into the sky. This molten rock is called magma when still inside the Earth, and lava after it has erupted. Hot springs are often found near volcanoes. Nature’s The spotter’s guide to volcano shapes fireworks This volcano is Spreading out Short and plump Going up putting on its The lava from shallow Cinder cones are a bit Composite volcanoes own spectacular shield volcanoes is bigger. They are made have pointed cones. fireworks runny, so it spreads of ash, which is lava Their lava is thick display. The out in a thin sheet. that has turned to dust. and sticky. explosions of red-hot lava and ash from the crater look like gigantic “Roman Candles.” 16

River of fire The red-hot molten rock that is streaming down the sides of this volcano is beautiful but deadly. It is so hot that it can melt steel. Clouds of ash Molten rock, called and gas pour out magma, rises up the from the crater. main pipe and any branch pipes. A volcano builds Mixed bunch up from layers of When lava cools and hardens, ash and lava. it can make rocks with different shapes. Here are three types: Branch pipe Aa lava Pahoehoe lava Magma collects in a A volcanic chamber found deep ‘bomb’ underground. It is forced up through cracks and holes in the ground. 17

EARTHQUAKES Our planet is a restless place. Several hundred times a day, the ground suddenly rumbles and Fires are started trembles. Most of the movements are so slight by broken gas that they are not felt. Others bring disaster. pipes and broken Big cracks appear in the land, streets buckle, and buildings electrical cables. crumble. Whole towns and cities can be destroyed. Then everything settles down but is totally changed. Earth has shaken and an earthquake has happened. Telephone lines brought down Cars are smashed and they settle at crazy angles. Unsafe ground On this side of the fault the This is the San Andreas Fault land has moved toward you. in California. Earthquakes regularly happen here. Terror from the sea Earthquakes under the sea can cause long, giant, destructive waves called tsunamis. An earthquake occurs along Tsunamis can travel many a fault in the seabed. miles across the ocean. 18

Why earthquakes happen Shaken up You may think that your feet The Mercalli Scale are firmly on the ground, but measures how much the Earth’s crust is moving all the surface of the Earth shakes time. It is made of moving parts during an earthquake. There called plates. When the plates are 12 intensities, or grades. slide past or into each other, At intensity 1, the effects the rocks jolt and send are not felt, but by intensity out shock waves. 12, the shock waves can be seen and there is total destruction. What to do in an earthquake Indoors, lie down under a bed or heavy table, or stand in a doorway or a corner of a room. After a minute, when the tremors will usually have finished, go outside, away from buildings, to a wide-open space. Earthquake words The place within the Earth where an earthquake starts is called the focus. The earthquake is usually strongest at the epicenter. This is the point on the Earth’s surface directly above the focus. The study of earthquakes and the shock waves they send out is called seismology. Fault line On this side Destructive force of the fault the A tsunami piles up and gets very tall land has moved before it crashes onto the shore. It is so away from you. powerful that it can smash harbors and towns and sweep ships inland. A tsunami can be more than 98 feet (30 meters) high and can travel as fast as a jet. 19

ROCKS Movements in the Earth’s crust are slowly changing the rocks that make up the surface of our planet. Mountains are pushed up and weathered away, and the fragments moved and made into other rocks. These rocks Sedimentary rocks may be dragged down into the Limestone These are made from bits mantle and melted by its fierce heat. of rock and plant and When a volcano erupts, the animal remains. They melted rock is thrown to the are broken into fine surface as lava, which cools pieces and carried by and hardens as rock. This is rivers into the sea. They broken down by weathering, pile up in layers and and so the cycle starts again. press together to Conglomerate make solid rock. The Painted Desert, in Arizona, is made of sedimentary rocks. In the beginning In time, material moved Red sandstone Rocks belong to three basic types. Igneous by rivers and piled up Rock fragments called rocks are made from magma or lava. The word in the sea will become sediments are carried igneous means “fiery.” Sedimentary rocks are sedimentary rocks. by rivers, glaciers, made in layers from broken rocks. Metamorphic the wind, and the sea. rocks can start off as any type. They are changed by heat and weight and the word metamorphic means “changed.” Recently formed sedimentary rocks 20

Igneous rocks Metamorphic rocks Marble These are made from These are igneous magma or lava. It cools or sedimentary rocks Slate and hardens inside the that are changed by Volcano Earth’s crust or on underground heat, the surface when it underground weight, erupts from a volcano. or both. This marble Sugarloaf Mountain in was once limestone, Brazil was once igneous a sedimentary rock. rock under the crust. The It was changed into rocks above and around marble by intense heat. it have been worn away. Obsidian Granite Some rocks are thrust up as mountain ranges Surface rocks are broken Glacier when the crust moves down by the weather and by and makes giant folds. the scraping effect of tiny pieces of rock carried in the wind or in the ice of glaciers. Molten rock that Magma that erupts cools and hardens from a volcano inside the Earth is becomes lava, and called intrusive forms extrusive igneous rock. igneous rock. Metamorphic rocks Folded rocks Magma 21

CAVES Going down Water dripping from the Caves are hollows beneath the surface of ceiling of a cave leaves the Earth. The biggest ones are all found behind a mineral called in rock called limestone and some are calcite. Very slowly, this grows downward in an icicle shape that is called a stalactite. huge. The world’s biggest cave, in Sarawak, is so large that you could fit 800 tennis courts in it.Yet these caves began simply as cracks or holes in the rock that, over thousands of The stream disappears underground into a pothole. years, were made bigger by rainwater trickling This pothole, or tunnel, into them and dissolving the surrounding rock. leads straight down through the rock. It was made by a stream wearing Limestone is a very common away the rock. rock. It is made from the skeletons and shells of tiny sea creatures that died millions of years ago. Drip . . . The rainwater that seeps into the ground is very slightly acidic and begins to dissolve the limestone. Drip . . . The rainwater continues to dissolve the rock. It widens the cracks into pits, passages and caves. Drip Over thousands of years, the passages and caves may join up to make a huge underground system.

Tunnel of lava Caves are found in rocks other than limestone. This one is made of lava and is inside a volcano in Hawaii. Cracks in the rock are Limestone pavements are widened when rainwater made when the rock seeps along them. dissolves along joint lines. Caving in Sometimes a cave turns into a gorge. This happens when the roof falls in to reveal underground caverns and, far below, the river that carved them. Cliff Gallery Cave mouth Stream Going up Where water drips onto the cave floor, columns of calcite, called stalagmites, grow upward.

OCEANS Sun With oceans and seas making up Earth 71 percent of the Earth’s surface, more than two-thirds of our planet Moon Ebbing and flowing is covered with water. Beneath the Tides are made by the waves lies a fascinating landscape. sun and moon pulling on Much of the ocean floor is a vast the oceans. When the sun, plain, but there are also trenches, Earth, and moon are in a line, there are large cliffs, and mountains, all larger spring tides. than any found on dry land. Ocean currents These show the directions in which water flows. Cold currents Warm currents Trenches can be deeper than the highest Underwater canyons are cut These underwater mountains on land. by currents flowing over the islands are seabed like rivers. called guyots.

Surface Lighted zone, up to 660 feet (200 meters) Going . . . Going . . . Gone Dark zone, up The water inside a Near the shore, the to 13,000 feet wave moves around and circular shape of the The top of the wave (4,000 meters) becomes unstable. around in a circle. It is wave is changed and When it hits the beach, Deepest zone, the wind that drives the it becomes squashed. a trench of wave forward. it topples and spills over. 36,200 feet (11,034 meters) Wind direction The dark depths Even in clear water, Ocean currents sunlight cannot reach The direction in which currents very far. The oceans move depends on winds and the become darker and Earth’s spin. Winds blow the top darker the farther down of the oceans forward, but the you go, until everything Earth’s spin makes the water turns inky black. below go in a spiral. Main current This island is a volcano A long, wide that has erupted from ocean ridge the ocean floor. Water, heated by Frozen worlds hot rocks, shoots In Antarctica and the back into the sea. Arctic, the oceans freeze. Molten rock rises Icebergs break away from up, cools, and glaciers flowing into the forms new water. Only a tiny part of seabed. an iceberg is seen above the surface of the ocean.

COASTLINES Some waves carry sand and pebbles from one part Have you ever built a sand castle and then watched of the coast and leave the sea come in, knock it down, and flatten it? them at another.This This is what happens to the coastline, the place makes a new beach. where the land and the sea meet. The coastline Headland changes all the time because, every few seconds of every day, waves hit the land and either wear it away or build it up into different shapes. Going, going, gone An arch When caves made on both sides of a headland meet, an arch is formed. If the top of the arch falls down, a pillar of rock, called a stack, is left. A stack A cave is made when seawater Some beaches are made in gets into cracks and holes in a bays between headlands cliff and makes them bigger. where the water is shallow and the waves are weak. Pounding away Waves pound the coastline like a giant hammer until huge chunks of rock are broken off. The chunks are then carried away by the sea and flung against the coastline somewhere else. 26

An estuary is the place From rocks to sand where a river flows Waves roll rocks and into the sea. boulders backward and forward on the shore. The boulders break into pebbles and then into tiny grains of sand. This change takes hundreds or thousands of years. Shifting sands Dunes are made of sand blown into low hills by the wind. Sea cliffs are one of the best places to see the different layers of rock. Mud flats Living rock and marshes Coral is found in warm, sunny, shallow Waves can build sand, mud, and seas. It is made by pebbles into a long strip of new tiny sea creatures that land. It is called a spit. look like flowers. Over thousands of years, their skeletons build up into huge coral reefs and islands. 27

GLACIERS Mountains Glaciers begin as huge snowfields. A glacier is like a huge river of ice that starts its life as a tiny snowflake. As more and more snow falls and builds up, in time it gets squashed under its own weight and turns to ice. A glacier moves very slowly downhill. Because it is very heavy, it can push rock along like a bulldozer. It can wear away the sides of mountains, smooth off the jagged The snow collects in bits from rocks, and move giant hollows and turns to boulders over dozens of miles. ice under its own weight. Glaciers usually move downhill very slowly, no more than a few inches each day. The ice begins to move and rub away the sides and bottom of the hollow. Little by little, it changes the shape of the land and makes it into a U-shaped valley. Close-up view Ice power The pilot in this plane is watching a wall When the water of ice break away from a glacier and in this bottle begin to crash into the water below. freezes and turns to ice, it takes up more room and breaks the bottle. When the water that makes up the ice of a glacier freezes, it takes up more room and pushes away the rock. 28

Rubble is carried along by the glacier. Shaping the land When you see a valley like this, you can tell from its U shape that it was once filled with the ice of a glacier. Melted ice Out of place flows as streams This giant boulder of hard and rivers beneath most glaciers. rock was moved by a Bumps in the rock glacier and left on soft can be smoothed limestone. Then, most out by the ice of the limestone was moving downhill. weathered away, leaving a small block Rocks carried along by The lower end of the glacier under the boulder. the glacier pile up when the is called the “snout.” Where a glacier flows glacier starts to melt and into water, chunks stops pushing them. 29 of ice break off and float away. When the glacier melts, it makes new rivers.

RIVERS A river usually begins Where the rock is in mountains or hills. hard, the river Rivers are very powerful, so powerful that Its water comes from makes rapids or the force of the moving water is able to rain or melted snow. waterfalls. change the shape of the land. As they flow through mountains and over plains, rivers Glacier carry away huge amounts of rock, sand, and mud. They then dump it somewhere else, usually on riverbanks or in the sea, to make new land. Over the top Oxbow lake When a river tumbles over the edge 30 of a steep cliff or over a hard, rocky ledge, it is called a waterfall. This one is in Brazil, South America. As the river flows quickly down steep slopes, it wears away the rock to make aV-shaped valley. Sand, mud, and gravel is left by the water as sediment.

Round the bend When a river reaches flat land, it slows down and begins to flow in large loops. It leaves behind sand, gravel, and mud, called deposits. This changes the river’s shape and course. River deep The river leaves A gorge is a deep, narrow valley carved by a river. deposits on the inside The Colorado River has made the largest gorge in bend and eats away the world—the Grand Canyon. It is 1 mile (1.6 km) the outer bend. deep and 227 miles (446 km) long. The deposits change the shape of the bend. In time, the neck of the bend narrows and the ends of the neck join up. River’s end This swampy land is part of the Yukon Delta in Alaska. A wide bend The river leaves behind or meander goes a loop. It is called an across flat country. oxbow lake because As it reaches the sea, of its shape. the river divides into Record rivers small streams, leaving The Nile, in Africa, is the longest river in the world. It is 4,130 miles a mass of sand, (6,650 km) long. The largest mud, and rock delta covers 40,500 square miles fragments, (105,000 sq km). It is made by the called a Ganges and Brahmaputra rivers, delta. in Bangladesh and India. 31

DESERTS Did you know that deserts come in many different forms? They can be a sea of rolling sand, a huge area of flat and stony ground, or mountainous areas of shattered rock. There are hot deserts and cold deserts. So what do these very different areas have in common? The answer is that they are all Tail dunes very dry and they all get less Wind than 10 inches (25 cm) of rain each year. This rain may not fall regularly. Sea of sand A desert may be hard to live in, Crescent dunes Instead, it may all come but it can be stunning to look at. in a single day and cause These dunes are in Saudi Arabia. a dramatic flash flood. A cuesta is a step of hard rock. Linear dunes Natural A large, steep-sided area rock arch with a flat top is called A butte a mesa. is a small, flat-topped hill. Star dunes Wind power Dunes Wind blows the sand Hard rock into hills which are that has been called dunes. These worn into a have different shapes pinnacle is called a and names. chimney or pipe rock. 32

On the move Imagine the hairdryer is the wind. It blows the sand up the gentle slope of the dune. When the sand gets to the top, it tumbles down the steep slope. As more and more sand is moved from one slope to another, the whole dune moves forward. Heavy rain makes Broken rocks slide Water power flash floods.These rush downhill and collect The tremendous power of water has made over the land, loaded with in gullies. this deep ravine near an oasis in Tunisia. sand and stones, and cut deep channels in the surface of the desert. Where the rock is hard, ridges will stand out in the landscape. Steep slopes Shaping the land of broken rock Wind-borne sand blows against Outwash fan the rocks and wears them into beautiful and surprising shapes. 33 Hot and cold This is one of the Devil’s Marbles in the Northern Territory, Australia. The rock’s outer layers have started to peel off because of the desert’s very hot and very cold temperatures.

SPACE The universe is made up of galaxies, stars, planets, moons, and other bodies scattered throughout space. A galaxy is a group of billions of stars: our galaxy, which is shaped like a spiral, is called the Milky Way. On a clear night, it is possible to see thousands of stars, which appear as twinkling points of light. The Earth’s moon is usually clear, and sometimes you can also see five of the planets: Mercury, Venus, Mars, Jupiter, and Saturn. These do not twinkle, but look like small steady discs of light. Earth is the third planet from the sun, which is about 93 million miles (150 million kilometers) away from us. People have always been curious about the things Space they could see in the sky. It is shuttle only quite recently, though, that science has developed the advanced technology needed to send people into space. Milky Way NEPTUNE URA NUS S AT U R N 34

MERCURY SUN VENUS EARTH MARS Asteroid belt JUPITER Rings 35

ROCKETS V-2 Rocket Gemini 1945 Titan 1964 Rockets were invented in China a long time ago. They looked a bit like arrows The Fly! and worked by burning gunpowder, which In 1931 Johannes Winkler burns up very quickly, so the rockets did launched his HW-1 rocket. not travel very far. Since then, people have It went 6.5 feet (two meters) tried many ways of sending rockets up into the air, turned over, into space. Modern rockets usually use and fell back to the ground. A two liquid fuels. They month later he tried again and mix together and burn. this time it climbed to 300 feet Then the hot gas shoots (90 meters) and landed 650 feet (200 meters) away. out of the tail, pushing the rocket up and away. 3, 2, 1, fire! A hundred years ago, soldiers used rockets like this. They were called Congreve rockets. Saturn power Fuel tank Saturn V is one of the Up, up . . . biggest rockets ever built. It is as How far can you throw a ball? tall as a 30-story building! It About 50 or 60 feet? It doesn’t was used in the Apollo program, go on forever because the which carried the first American Earth’s gravity pulls it back astronauts to the moon. down again. See it go! The If you blow up a balloon stabilizing and let it go without tying a fins keep knot in the neck, the air will the rocket rush out very quickly. When on course. the air goes out one way, it Five rocket pushes the balloon the other engines way—just like a rocket! 36

Quest for power Service Launch As rockets have Module Escape become more System powerful their Command Module shapes have changed. The latest ones carry shuttles into space. Soyuz 1967 Space Shuttle Lunar 1981 Module Rocket engine Overpowering See just how enormous Saturn V’s engines are compared to these people! Five rocket engines . . . and away Safe landing To escape from Earth by The Falcon 9 rocket can leave Earth and rocket you have to travel at soar into outer space 25,000 miles (40,000 before returning safely kilometers) per hour— to Earth afterward and more than 40 times doing it all over again. faster than a jet. 37

MMOOISNSION The second stage The Command and Service drops off when its Modules turn, join onto the five engines run Lunar Module, and pull it out of the third stage. out of fuel. The moon is the Earth’s nearest Astronauts who are going neighbor in space, but it still takes three to the moon crawl days to get there by rocket. It would take through a tunnel from 200 days by car! When astronauts first the Command Module to the Lunar Module. went to the moon no one could be sure it would be safe to land there. But now American astronauts Second have been to the moon stage on Apollo missions six times and they all returned safely to Earth. The first moon trip was in 1969 and the last in 1972. We have liftoff! This air recycling Lunar Module The first stage of the unit keeps the air Saturn V rocket has fresh in the cabin. ck to Earth five huge engines. down When these run CSM = Command and out of fuel they Service Modules fall back to Earth. LM = Lunar Module Then the second CM = Command Module stage takes over. CSM docks with LM LM b CSM in orbit Liftoff oon Earth CSM ba Splash lashes down Moon ack to CSM CM sp LM descends to m Moon trail The Apollo missions to the moon followed a path in the shape of a figure eight. 38

The Lunar Module drops down The top part of the to the moon with two astronauts Lunar Module returns inside.The Command Module to the Command Module. stays in orbit around the moon. The Command Module ComMmodaunlde There is not much falls to Earth, using room in the cabin parachutes to make for three astronauts. a safe landing in the sea. Engine nozzle Service Module Parachute Fuel tanks Splashdown! This Command Module fell through the Earth’s atmosphere so quickly that the bottom got burned. It splashed down in the sea and was picked up by a helicopter. The balls on the roof are air balloons which helped it to float upright if it turned over in the water.

LULNAANRDING Mission patch A lunar landing is a moon landing. If you went to the moon you would find The Apollo 11 crew nothing living at all, no air, and no water. Neil Armstrong and Edwin If you stayed for a lunar “Buzz” Aldrin were the “day”—about 28 Earth first men to walk on the days—you would have moon. Michael Collins two weeks of baking sun stayed in orbit in the followed by two weeks of Commmand Module. freezing night. The first men on the moon went down in the Lunar Module, named “Eagle.” Antenna Hanging out the laundry? No, just setting up a panel to collect dust! The moon is covered in dusty soil and scattered rocks. Control panel Television Hand control camera Sample collection bags Seats Space Wire-mesh Moon buggy for storing wheel This buggy was equipment taken to the moon for the first time in Apollo 15. Its proper name is the lunar roving vehicle. 40

Weather or not? Escape With no wind or rain, tower the footprints made by Command the astronauts will module remain on the moon Service forever. The American module flag, left on the moon by the astronauts, is held out by a metal bar because there is no wind to make it fly. These Lunar Third stage engines module help the astronauts to control the Lunar Module. Forward hatch door The astronauts carry Second stage radio packs. Sound cannot travel without air, so the astronauts use radios to talk to each other. Ladder One of the four fold-up Super Saturn First stage “spider” legs.The first The Saturn V Foot with rounded Lunar Module was called has three stages. pad to stop the leg “Spider,” but that mission When one stage from sinking into didn’t land on the moon. runs out of fuel the ground. it falls off and Earthrise 41 another part The Lunar Module is just leaving the takes over. moon. Behind it you can see what Earth looks like from the moon.

MERCURY AND VENUS Crust Between the Earth and the sun MERC Iron core Magellan are two planets called Mariner 10 Mercury and Venus. Hard center They are very hot URY If you could slice Mercury like a because they are peach, you would the sun’s nearest find it had a core neighbors. Venus made of iron. is the brightest object in the night sky. Mercury is the smallest planet in the solar system. Photographs from space probes Antenna tell us more about these planets. Hello, goodbye! The solar detector Mariner 10, intended to made sure that explore Mercury and Venus, the solar panels was the first probe to visit two were always Solar panel planets in a row. It worked for facing the sun. Television cameras Star 17 months before breaking sent pictures back detector down. Launched in 1973, it is to Earth. now in orbit around the sun. Dish antenna Earth orbit Mariner orbit Venus Mercury orbit Earth sun Venus Mercury orbit The Journey Happy new year of Mariner 10 Mercury travels fast through space and is the closest planet to the sun. The Earth orbits the sun every 365 days— one Earth year. Mercury’s year is 88 days. 42

The space probe Venera 9 was in a capsule on Venus theVenera spacecraft. landing Wish you were here? The brake is The capsule fell The Magellan probe used shaped like a disk through the radar cameras to take pictures to help slow down atmosphere through the thick fog around the space probe. of Venus. Venus. Computers made this 3-D image of the volcanoes. The heat shield Venus Venera covers separated Several Russian missions and fell off. went to Venus between 1961 and 1984 in Instrument The probe a program called Venera. container was slowed The spacecraft sent pictures down by back to Earth. This is a small the part of Venera 9 parachute. that went down to Venus by parachute. The landing ring helped to make the VENUS landing soft. Hot orange Three larger Venus has a dense parachutes were used atmosphere that traps heat for the from the sun. It is the final stage. hottest planet of all—so After a safe hot it could melt lead! landing, the It has a bright orange television cameras sky with flashes of and instruments lightning. Earth were switched on. spins around once every 24 hours, but Venus spins very slowly —once every 244 days! 43

TPHLEARNEEDT Viking spacecraft TheViking lander is folded into a capsule on the spacecraft. It leaves the orbiter and begins Mars is called the Red Planet because its soil and its journey down rocks are red. Light winds blow dust around, to Mars. which makes the sky look pink. People once thought there was life on Mars, but nothing living has been found so far. The Viking spacecraft were sent to Mars to The television camera takes a series of pictures find out what it is like. Two missions, Viking 1 as it moves around. and Viking 2, made the journey. Perhaps one day people may go to It moves so fast live on Mars that it gets very hot. because it is the A parachute is planet most like used to slow it our own. down, and then the heat shield drops off. This remote control arm is used to collect samples of Mars soil. Tight fit The legs unfold, The Viking lander and rockets are fits into a capsule used as brakes for on the spacecraft. a soft landing. With its legs folded up, it looks a bit like a tortoise inside its shell. The Viking lander 44

Antenna Surface of Mars Other spacecraft have Satellite dish been to Mars since the The color test card Viking missions. This checks that the camera image of a huge crater shows the correct colors. was taken in 2015 by the Mars Reconnaissance This container Orbiter. is for soil Red desert samples. Mars is very cold. It has lots of dead volcanoes, craters and dried-up rivers. It looks like a rusty, rocky desert. Weather instruments Landing shock absorber Leggy landers The Viking spacecraft took about a year to reach Mars. The landers tested soil and sent pictures back to Earth. The landing feet have rounded pads to stop the legs from digging into the soft soil. 45

JUPSITAETRURANND These two giants are the largest planets in the solar system. Jupiter is made of gas and liquid so it is not solid enough to land on, but if you could drive a car around its equator it would take six months of nonstop traveling. A similar journey around Spinning Saturn Earth’s equator would Saturn is a giant spinning ball of gas take only two weeks. and liquid held together by gravity. This photograph shows a storm rotating over the north pole. Saturn is a beautiful planet with shining rings around its middle. Both planets spin around very fast, pulling the clouds into stripes. Radio A power supply is carried on antenna the probe. It does not use solar power because it is working so far from the sun. S AT U R N This disk Dish Seven cold rings has pictures of antenna Saturn’s rings are Earth and sounds, made up of glittering such as a baby pieces of ice like crying and music. trillions of snowballs. If aliens find the disk it will tell Voyager voyages them about The probes sent to explore Earth. Jupiter and Saturn were called Voyager. Voyager 1 did its job so Television well that Voyager 2 was rerouted cameras to go on to Uranus and Neptune. 46

Pioneer picture Power supply The program for sending Asteroid and unmanned spacecraft to meteor detector Jupiter was called Pioneer. Pioneer 10 succeeded, so 11 went on to Saturn. Both sent back lots of pictures. Pioneer Mega moons Dish Jupiter has 79 moons circling antenna around it. The largest is Sun called Ganymede. It is sensor bigger than Mercury. Jupiter Earth Pioneer 10 Jupiter orbit Saturn IT Saturn orbit ER Pioneer 11 Uranus Uranus orbit Voyager 1 Voyager 2 Neptune P JU One-way ticket The journeys of Pioneer 10 and 11 and of Voyager 1 and 2 passed several of the planets. These spacecraft are now heading for the stars. Red storm Jupiter, like Saturn, has a small, rocky core surrounded by liquid. It has icy clouds and a giant red spot which is the center of a huge storm. Swirling winds blow Jupiter’s clouds into a hurricanelike storm. 47

T OHE UTER UR Sideways spinner PLANETS ANUS Uranus looks as if Uranus and Neptune are the farthest it is spinning on its planets from the sun so they are called the side. It is covered outer planets. They are very cold. Uranus in dense fog. was the first planet to be discovered using a telescope because you cannot see it from Outer solar system Earth just with your eyes. Pluto orbits outside Neptune and used to be classed as the ninth planet of the The rings of Uranus solar system until 2006, when it are made of rocks. was reclassified as a dwarf planet. The widest ring is 62 miles (100 kilometers) across. There are many other dwarf planets in the solar system, including Cerea, Eris, Haumea, and Makemake. Ellipses This diagram shows the The planets move around orbits of the planets and their the sun in squashed circles places in the solar system. called ellipses.This girl is It does not show their sizes. drawing ellipses. Order of orbits The word planet means wanderer. The planets travel around the sun in paths, called orbits. The ones nearer the sun have shorter orbits than the ones farther away. One way of remembering the order of the planets in the solar system is to remember the sentence “My Very Educated Mother Just Served Us Noodles.” 48