CONTENTS RECORD BREAKERS Earth and Universe · 2016-10-27 · launched from Earth must go faster...

RECORDBREAKERS

CONTEN T S

Earth andUniverse

by Storm Dunlop

RBs Earth and Univ all.qxb:RBs E&U NEW 30/10/08 17:26 Page 2

© 2008 Orpheus Books Ltd

Illustrations by Sebastian Quigley(Linden Artists), Alessandro Bartolozzi,Luigi Galante (The McRae Agency),Julian Baker, Gary Hincks, Colin Rose,Roger Stewart

Created and produced by NicholasHarris and Joanna Turner, OrpheusBooks Ltd

All rights reserved. No part of thisbook may be reproduced, stored in aretrieval system, or transmitted in anyform or by any means, electronic,mechanical, photocopying, recordingor otherwise, without the priorpermission of the copyright owner.

ISBN

Printed and bound in

Picture acknowledgements: 43Popperfoto Ltd

STARS OF THE NIGHT SKYA Guide to Stellar RecordHolders � The Brightest Stars

THE LARGEST STARBetelgeuse, the Size of 800Suns � The Life and Death ofa Star � The Largest Stars �

The Smallest Stars

BLACK HOLESThe Densest Objects in theUniverse� Massive Energy Machines

THE NEAREST STARA Shimmering Ball of Gas� Daytime Darkness

THE PLANETSSolar System Record Holders

TO THE CENTRE OF JUPITERGiant among Planets � TheGreat Red Spot

THE HOTTEST PLANETBeneath the Clouds of Venus� Meteoroid Bombardment

THE HIGHEST MOUNTAIN......in the Solar System� The Red Planet

THE LARGEST MOONSWorlds of Ice and Rock� The Smallest Moon

22

20

18

1614

12

10

8

6 HALLEY’S COMETThe Brightest Short-PeriodComet� A Cometary Journey� What is a Comet?

EARTH RECORD HOLDERSOur Home Planet � TheLargest Lakes � The LongestRivers � The Largest Islands

THE GREATEST OCEANThe Mighty Pacific� Beneath the Ring of Fire

THE GREATEST MOUNTAINSThe Mid-Oceanic Ridge� Volcanoes under the Sea

THE HIGHEST MOUNTAINSThe Towering Himalayas� Colliding Plates

THE GREATEST RIFTAnd the Longest River� The Nile � EastAfrica SplitsApart

34

32

30

28

26

24 THE LARGEST GORGEThe Spectacular Grand Canyon� History in the Rocks

THE DEEPEST LAKEBaikal, Blue Eye of Siberia � AGiant Chasm � A Climate of ItsOwn

THE GREATEST EXPLOSIONA Volcano Blows � Under aVolcano � Famous VolcanicEruptions of the Past

40

38

36 THE GREATESTQUAKEThe Great Chilean Quake �

Giant Waves � Some GiantEarthquakes

THE MOST VIOLENT STORMThe Deadly Tornado � TheTri-State Twister

INDEX

42

44

46

I N T RODUC T I ONImagine a star so gigantic that, even if you travelled in the fastest

plane, it would take over 500 years to fly round it. Yet there areother stars, called black holes, so incredibly tiny they are smaller

than the ball from a ball-point pen! Even though some black holesare unbelievably distant, astronomers can still detect where theseobjects are.

Our own Solar System also contains many astonishing recordholders. Tornadoes on Earth are extremely destructive, but winds onSaturn are more than ten times as fast. The swirling storm of theGreat Red Spot on Jupiter is twice the size of the Earth itself, whilesome sunspots can be more than twenty times as large. Venus is sohot that any astronaut who landed there would be immediatelyincinerated, while Pluto is so cold (below -200 degrees Celsius) itssurface is made of frozen gases.

How does Earth’s Grand Canyon compare with the giant valleyson Mars? Where is the world’s deepest lake, its highest mountain,and its longest river? When did the most powerful earthquake everrecorded occur? Find the answers to these and many more questionsin this book.

CON T EN T S


The largestconstellation,which is calledHydra after themythical sea monster(above), contains about68 stars visible to the eye (notall shown here) and coversabout 3 per cent of the wholesky.

Imagine flying in supersonic jet at a cruisingspeed of 2000 km/h. It would take nearly200,000 years to reach the nearest star!

Distances in the universe are so vast that we haveto use a special measure called light-years. Lightmoves at 299,792 kilometres per second (it wouldtake the aircraft nearly five-and-a-half days tocover the same distance). In a year, light travels

about 9,460,528,405,000 kilometres, so we can use thisdistance, a light-year, instead of reckoning in millionsand millions of kilometres. Powerful telescopes candetect quasars, central regions of galaxies throwing outenormous amounts of light and heat far out in theuniverse. They are the farthest objects known. The mostdistant quasar so far discovered is about 13,200,000light-years away!

A gu i de to s t e l l a r r e co rd ho l de r sS T AR S OF THE N IGH T SKY

AQUARIUS

VIRGO

LEO

CANCER

GEMINI

BOOTES

URSA MAJOR

URSA MINOR

ORION

TAURUS

AQUILA

PISCES

PEGASUS

VIRGO

LIBRA

ORION

CENTAURUS

AQUARIUSCETUS

PISCES

CAPRICORNUS

These two charts showthe night sky visiblefrom the NorthernHemisphere (left) andSouthern Hemisphere(right). (Over thecourse of a year, thepart you can seevaries.) The brighterstars are shown aslarger spots. The linesbetween the stars linkthose stars together inthe same constellation.

THE BRIGHTEST STARS1 Sirius2 Canopus3 Alpha Centauri(Rigil Kent)

4 Arcturus5 Vega6 Capella7 Rigel8 Procyon9 Achernar10 Hadar11 Altair12 Betelgeuse

STAR RECORD HOLDERSA M31 galaxy Farthest object easily visible to the eye2.5 million light-years away

B M33 galaxy Farthest object ever visible to the eye2.6 million light- years away

C Sirius Brightest star 8.6 light-years awayD Canis Major dwarf galaxy Nearest galaxy 50,000 light-years awayE VY Canis Majoris Largest star 2100 times the size of the SunF Hydra Largest constellationG Eta Carinae Most massive star 200 times the mass of the SunH Crux Smallest constellationJ Proxima Centauri Nearest star 4.2 light-years awayK Alpha Centauri (Rigil Kent) Second nearest star and nearest visibleto the eye 4.4 light-years away

6 7

NORTHERNHEMISPHERE

SOUTHERNHEMISPHERE

A

C

F

B

DE

CANIS MAJOR


THE LIFE ANDDEATH OF A STARStars are formed when clouds of gasand dust in space (1) shrink tobecome dense ‘blobs’ calledprotostars (2). The same force thatkeeps us firmly on the ground –gravity – causes this to happen.The core of the new protostarbecomes so hot that nuclearreactions (see page 12) startdeep inside it. Gas and dustare blown away by aviolent ‘wind’ from thestar (3). Sometimes aspinning disc of dust, gasand ice results (4). Thismay eventually becomethe birthplace ofplanets.

The fuel that powersthe nuclear reactionslasts billions of years (5).When it runs out, thecore collapses and the

Supergiant stars are so big that perhaps theonly way to imagine just how big they are isto compare them with the orbits of planets inour Solar System (below). Betelgeuse wouldengulf Mercury, Venus, the Earth and Mars –all the inner planets circling round the Sun.The supergiant VY Canis Majoris wouldconsume Jupiter and Saturn as well!

THE LARGEST STARSVY Canis Majoris 2100VV Cephei B 1600V354 Cephei 1520KW Sagittarii 1460Mu Cephei 1420

(times the size of the Sun)

outer regions grow into redgiants (6). Most stars, includingour Sun, are destined to becomered giants, but some muchheavier ones become supergiants(7).

When its nuclear ‘fuel’ runsout, a supergiant’s core willcollapse in a split-second. Theoutside explodes as a supernova,the greatest explosion known inall nature (8). For a fraction of asecond, a supernova will give offmore energy than all the billionsof stars – in every one of thebillions of galaxies – all puttogether! All that is left behindafter the explosion is a denseneutron star (9) or a black hole(see page 10).

THE SMALLEST STARSStars like the Sun are so small when compared withgiants and supergiants that astronomers call themdwarfs. A teaspoonful of material from the Sun is asheavy as a spoonful of syrup. After the Sun swells tobecome a red giant (in about five billion years) it willlose its outer layers. Just the small, very hot, deadcore will remain. Called a white dwarf, it willmeasure about 10,000 km across (roughly the size ofthe Earth) and be extremely dense. A teaspoonful ofwhite-dwarf material would weigh five tonnes.

The core that remains after a supernova explosionis a tiny star no more than 25 km across, known as aneutron star, the smallest type of star that exists. Ateaspoonful would weigh an incredible one billiontonnes!

Compared to other types of star, neutronstars are incredibly small. Here (above) onecompares in size with the city of New Yorkas seen from the air.

THEY MAY LOOK like tiny points of light inthe night sky, but stars can be enormous –

sometimes millions of times the size of ourEarth. The very largest stars, called supergiants,are unbelievably huge! Betelgeuse, the brightred star in the constellation Orion, is thelargest one visible without a telescope. About1 billion kilometres across, it is 800 times thesize of the Sun, our own ‘local’ star.

Because they are so far away, it is verydifficult to measure the sizes of stars. Accordingto latest observations, VY Canis Majoris is thelargest known. It may measure up to about 2100times the size of the Sun.

9

Be te l geu se , t he s i z e o f 8 0 0 Sun sT H E LARGES T V I S I B L E S TAR


Completely invisible, black holes are the strangestobjects in the universe. Like neutron stars (seepage 9) they are all that remains of stars that

have blown up in supernova explosions.All bodies in space have a force of gravity, the

force which attracts other things towards them. It isthis force that holds stars together, keeps the planetsin their orbits around the Sun, and causes all objectsto fall to the ground on Earth. To escape from a staror planet, you would have to travel at very highspeeds to overcome the force of gravity. A rocketlaunched from Earth must go faster than 40,320km/h to escape from the Earth’s gravitational pull.

After a supernova explosion, the central corecollapses until it is a tiny fraction of the size it usedto be. No more than a tiny pin-point in space, it isnevertheless surrounded by a force of gravity morepowerful than any normal star in the universe. Inorder to escape from here, you would have to travelfaster than the speed of light: 299,792 kilometres persecond!

You can think of the force of gravity being likea ball on a rubber sheet. A star or a planet‘bends’ space: anything close by will falltowards them. If the ball got so heavy thatpart of the sheet stretched into a long, thintube, you would have a black hole.

In fact, escape would be impossible because nothingcan travel faster than the speed of light. That is whythese mysterious, invisible objects are called ‘blackholes’: nothing, not even light, can escape from them.

No one has ever seen a black hole, but astronomersbelieve that they exist because they can detect theirpowerful gravitational force.

MASSIVEENERGY MACHINESIncredibly powerful, giant blackholes, astronomers think, lurk in thecentres of galaxies. In some galaxies, such asour own Milky Way, the black holes are fairly peaceful.In others, they are the scene of violent activity. As stars aresucked in towards them, they are torn apart into clouds of gas.Quasars, the most distant objects in the universe are probably the centralregions of such violent galaxies. The energy they give out is so great they can stillbe detected even though the galaxies themselves are too far away to be visible.

The pair of stars calledCygnus X-1 almostcertainly contains ablack hole. We can seea supergiant star(above) circlingsomething invisible withan enormousgravitational pull. Thestar is losing gas, whichswirls down into theblack hole.

Billions of light yearsaway, an enormous,swirling disc of gassurrounds a giantblack hole in thecentre of a quasar (seebelow). The incredibleenergy blasts two jetsof gas out into space.

10 11

BLACK HOLE S The den se s t ob j e c t s i n t he un i v e r s e


TH E NEARE S T S TAR

The nearest star to Earth is the Sun itself. Agigantic ball of extremely hot gases, mostlyhydrogen and helium, it is big enough to

contain nearly 1,400,000 bodies the size of ourown planet. It dwarfs even the largest planet,Jupiter. In fact, the Sun contains more than99 per cent of all the matter in the SolarSystem. The Sun also provides most of theheat in the Solar System, and thus thewarmth that makes life possible on Earth.

The surface, called the photosphere, is inconstant motion, like water in a boiling kettle.Its temperature is about 6000˚C, but at thecentre this rises to an incredible 15 million˚C! Thecore generates all the Sun’s energy through whatare known as nuclear reactions. At such hightemperatures, hydrogen is changed to becomehelium in a reaction that gives off an enormousamount of energy. (This is called nuclear fusion,the same process that scientists hope one daywill drive the world’s power stations.)

Incredibly, scientists have created temperaturesfar hotter than at the centre of the Sun. Plasma,produced when gases are subjected to very hightemperatures, is the hottest known matter. At thePrinceton Plasma Physics Laboratory, New Jersey,USA, scientists achieved a temperature of 510million˚C.

The Sun ‘burns’ about 4 million tonnes ofhydrogen every second, but it is soenormous that, fortunatelyfor us, it will takeanother 5 billionyears before itfinally exhaustsits supply!

Prominences (above)are clouds, tongues orarches of glowing gasheld above the Sun bymagnetic fields. Someprominences last forweeks, but other,more violent onescome and go withinhours. Manyprominences aregigantic. The highestarches are often morethan 600,000 km high,twice the distancefrom the Earth to theMoon.

Sunspots are thecoolest parts of theSun’s surface: they are‘only’ 4300˚ C. In 1947,the largest group everseen covered 18,130million sq km. It wasroughly 300,000 kmfrom end to end, twicethe diameter of Jupiter,and about 23 times thesize of the Earth.

In this illustrationof the Sun, asegment has beenremoved so thatthe layers insideare visible.

Sunspots

ConvectiveZone

RadiativeZone

Core

JUPITER(to scale)

EARTH(to scale)

12 13

Sudden explosions of energy, flares arethe most violent events on the Sun’ssurface. In a few minutes the strongesteruptions release as much energy asthe entire Sun does in a few seconds.One of the greatest flares of recenttimes happened on 10 August 1989. Itblacked out the power supply inQuébec, Canada.

A sh immer i ng ba l l o f g a s

DAYTIME DARKNESSDuring a solar eclipse, the brightsurface of the Sun is hidden behind theMoon, and the faint, pearly-whiteouter atmosphere, known as thecorona, becomes visible (below).

Eclipses last a maximum of 7minutes 30 seconds (usually much

less). It may be 500-600 yearsbefore another eclipse isvisible from the same pointon the Earth’s surface.


Mercury is the smallestplanet, and the closestplanet to the Sun. Itrushes round it in 88days, the quickest orbitof any planet.

The hottest planet,Venus spins slowly, soit has the longest day.On its orbit, it comescloser to Earth thanany other planet.

THE INNER PLANETSMERCURY Diameter 4878 kmDay 58.6 Earth days Year 88 days. nomoons; bare, rocky surfaceVENUS Diameter 12,103 kmDay 243 Earth days Year 225 days. Nomoons; hot, cloud-coveredEARTH Diameter 12,756 kmDay 23 hrs 56 min Year 365.26 days. 1moon; extensive oceansMARS Diameter 6794 km Day 24.6 hrsYear 687 Earth days. 2 moons; dry,dusty, little atmosphere

Mars is a very cold anddry planet. It has thehighest mountain inthe Solar System.

Jupiter is larger thanall the other planetsput together. It spinsfaster and has theshortest day of all.It also has the mostmoons (63).

THE LARGEST PLANETS in the Solar System – Jupiter,Saturn, Uranus and Neptune – are known as the gas

giants because, unlike our rocky planet, they consistmostly of gases, particularly hydrogen and helium.Jupiter and Saturn probably have rocky cores, but theothers may only have liquid water and methanebeneath their gassy exteriors.

The gas giants all have many moons, some of which arelarger than Mercury, the smallest planet. The giant planetsalso all have rings, although except for Saturn’s they arevery faint. Saturn’s bright rings extend for 273,000kilometres, more than twice the diameter of the planet.They consist of millions of blocks of ice, the largest ofwhich are about 10 metres across – the size of smallhouses.

Now officially classified as a “dwarf planet”, Pluto ismostly made of ice. Its orbit around the Sun is moreelongated than those of the other planets, so that some ofthe time it is actually closer to the Sun than Neptune.

The four, small, inner planets – Mercury, Venus, Earth,and Mars – are mainly made of rock. Between Mars andJupiter, thousands of asteroids (also called minor planets)orbit the Sun. The largest, Ceres, another dwarf planet, is1003 kilometres across.

The Sun and planets are illustrated to scale

Saturn has the largestrings of any planet inthe Solar System. Ithas the lowest density– even less than thatof water.

Uranus was the firstplanet to bediscovered with theuse of a telescope.

Now that other, larger worlds have beendiscovered, astronomers have re-classified Plutoas one of several dwarf planets.

Neptune is the farthestplanet observed by anyspace probe.

MERCURYVENUS EARTH

SATURN

JUPITER

Mercury

Venu

sEarth

Mars Asteroids Jupiter Saturn Uranus Pluto

(when nearestthe Sun)

PlutoNeptune

URANUS

PLUTO

NEPTUNE

MARS

SUN

15This diagram shows the planets’ relative distances from the Sun.

THE OUTER PLANETSJUPITER Diameter 142,884 kmDay 9.8 hrs Year 11.8 Earth years. 63moons; tiny ringSATURN Diameter 120,536 kmDay 10.2 hrs Year 29.4 Earth years. 60moons; giant ringsURANUS Diameter 51,118 kmDay 17.2 hrs Year 84 Earth years. 27moons; 11 thin ringsNEPTUNE Diameter 50,538 km Day16.1 hrs Year 164.8 Earth years. 13moons; 2 thin ringsPLUTO Diameter 2324 kmDay 6.4 days Year 248 Earth years. 3moons; mostly made of ice

TH E P LANE T S So l a r S y s t em reco rd ho l de r s


WITH A DIAMETER more than 11 times that of ourown planet, Jupiter – the largest of all the

planets – could contain a thousand Earths! Its gravity(the force that attracts other things towards it) is sostrong that it often alters the orbits of comets thatpass close by (see page 24), sometimes hurling themout of the Solar System altogether.

Jupiter’s day is shorter than that of any other planet:just under 10 hours. Because it rotates so fast, it bulgesat the equator and measures 8600 kilometres less from

The Great Red Spot ishere compared in sizewith the Earth, drawnto the same scale(below). The Spot actsas an obstruction tothe violent winds thatblow round theplanet. Other whiteovals, like the onevisible here, aresimilar, but smaller,storms.

Fast-moving clouds, the beltsthat circle Jupiter’s globe,constantly change shape. Afaint, dusty ring, probablyonly a few kilometres thick,also surrounds the planet.Jupiter’s most famous featureis, however, the Great RedSpot, located here in thered box and seen ingreater detail onthe oppositepage.

pole to pole. Jupiter has no solid surface: only its smallcore (with a diameter more than twice that of thewhole Earth) is made of rock and metals. Most of theglobe is liquid – not water, but a metallic form ofhydrogen close to the core and, beneath the clouds nearits surface, liquid hydrogen.

Like the other outer planets, Saturn, Uranus andNeptune, Jupiter is surrounded by swirling clouds of gas.Divided into bright zones and dark belts, Jupiter’s cloudsare separated by bands of high-speed winds. Somereach speeds of 540 km/h. (Saturn holds the record,however, with winds of up to 1800 km/h – fasterthan the speed of sound on Earth!)

This illustration shows what you would find ifyou were to tunnel through the Great RedSpot towards the centre of Jupiter. A littleway below the cloud layers there is liquidhydrogen and, deeper still, a strange‘metallic’ form of liquid hydrogen. Right atthe centre, there is a core made of rock,originally the ‘dust’ that swirled in the vastcloud from which the Sun and planets wereborn (see page 8).

THE GREAT RED SPOTThe Great Red Spot is like a gianthurricane that has been raging formore than 300 years (hurricaneson Earth last only a few days). Thevast oval of swirling clouds isabout 25,000 km across – twicethe size of the Earth – and about40 km above the level of most ofthe other clouds. The Spot‘stopmost clouds turn in an anti-clockwise direction, taking aboutsix days to make one full turn. Itgets its brick-red colour, scientistsbelieve, from the chemicalsubstance phosphorus.

Beneath the Spot’s surface,there are warmer layers where theclouds are made of ice crystals andwater droplets like those on Earth.

16 17

Rocky,metallic

core

Metallichydro

gen region

Liquidhydro

gen region

Regionof clouds

TO THE C EN TR E OF JUP I T E R G i an t among p l ane t s


VENUS IS THE NEAREST PLANET to Earth, but noworld could be an unfriendlier place to visit! In

any case, were you ever to set foot on its surface,you would be immediately incinerated. Venus is thehottest planet in the Solar System: its averagetemperature of 490˚C is easily enough to melt lead.It is even hotter than Mercury, although that planetis much closer to the Sun. This is because Venus’s

thick atmosphere of carbon dioxide – so dense that itwould crush any person not already burnt to a cinder– prevents heat from escaping.

Most of the barren surface is covered by vast plains,studded with tens of thousands of volcanoes. Themountain known as Maxwell Montes is nearly 12,000metres high, the second highest in the Solar Systemafter Olympus Mons (see page 20) on Mars.

There is no wateranywhere on Venus,and heavy clouds ofdeadly sulphuric aciddroplets prevent directsunlight from reachingthe surface. There areseveral layers ofclouds, but at thesurface theatmosphere is clear.

These extraordinaryrocks are domevolcanoes – alsoknown as pancakes.Liquid rock has oozedto the surface andcooled down in acircular pattern.

TH E HO T T E S T P LANE T

Modern technologyhas found a way toshow us pictures ofwhat Venus reallylooks like. Anunmanned spacecraftcalled Magellan (left)has mapped theplanet’s surfacebeneath the clouds. Itused radar, the samedevice ships andaeroplanes have todetect other craft outof direct vision.

METEOROID BOMBARDMENTMany meteoroids – fragments of rock and ice shooting around theSolar System – are completely destroyed in the dense atmosphere ofVenus before they get near the ground. Some explode in mid-air,creating strange ‘splotches’ where the shockwave from the explosionshatters the rocks on the surface below. The largest meteors smashinto the ground with tremendous force, flinging rocks in alldirections. The largest craters are about 110 km across.

19

Benea t h t he c l oud s o f Venu s


TH E H I GHE S T MOUNTA IN . . .

OLYMPUS MONS, the giant volcano on Mars, towers24 kilometres above the surrounding land. Nearly

three times as high as the highest mountain on Earthand about twice as high as the greatest mountains onVenus, Olympus Mons is the highest mountain in theSolar System.

Like many volcanoes on Earth, Olympus Mons burstinto life at a ‘hot spot’. This is a place where a plume ofvery hot, liquid rock from deep below the surface meltsthrough a planet’s outer crust. On Earth, the outer crustis constantly on the move, a fractured armour of ‘plates’sliding against, alongside, or beneath each other(see page 32). Hot-spot

volcanoes – like the Hawaiian Islands in the PacificOcean – appear at the surface in different places as acrustal plate wanders over the molten spot.

Unlike the Hawaiian volcanoes, Olympus Mons stayedput above its ‘hot spot’. The eruptions and lava (liquidrock) flows have gone on for tens – perhaps hundreds –of millions of years. As each layer of rock cooled, thevolcano grew larger and larger. It now measures about600 kilometres across.

Olympus Mons lies on the edge of a giant bulgein the surface of the planet Mars, the TharsisRidge. Among its volcanoes are threeother giants, Ascraeus, Pavonis andArsia Mons, all about 17 kmhigh – twice the heightof Mount Everest,Earth’s highestpoint abovesea level.

The highest mountain range on Earth, theHimalayas (seen here in cross-section asa grey silhouette) would be completelydwarfed by Olympus Mons – in bothdirections. Mount Everest, the highest

peak, measures 8848 m to OlympusMons’ 26,400 m! And just five mountainsthe size of Olympus Mons placed side byside would be roughly as long as theentire Himalaya range (see page 33).

THE RED PLANETMars is the red planet. Its colour comes fromsubstances containing iron, similar to ordinary rust, inits surface rocks. Nearly 80 million km farther from theSun than Earth, Mars is a cold world. Sometimes thetemperature reaches the melting point of water (0˚C)at the equator in high summer. In winter, it plunges tobelow -120˚C over the poles, which are capped bylayers of frozen carbon dioxide and water ice. In thenorth, an expanse of water ice remains frozen in thesummer. It is surrounded by the largest area of sanddunes known in the Solar System, stretching almostcompletely round the planet.

Now a dry and dusty place, a great deal of wateronce flowed over the Martian surface. Dried-up riverbeds are all that remain. One, Vallis Marineris, is agigantic rift valley (see page 35) about 4000 km long,nearly enough to reach from coast to coast of theUnited States. Parts of it are about 6 km deep, nearlyfour times as deep as Earth’s greatest gorge, the GrandCanyon (see page 36).

20 21

OlympusMons

PavonisMons

AscraeusMons

ArsiaMons

Area of inset(opposite)

. . . i n t he so l a r s y s t em


Saturn’s moon, Titan, 5150 km across, is the onlymoon in the Solar System with a thick atmosphere(a gas envelope surrounding the globe). Denseclouds permanently hide the surface from the Sun.Recent pictures sent back by the lander Huygensshow drainage channels and lake beds, bothproduced by liquid methane.

Jupiter’s four largest moons are all in the topseven. They are called the ‘Galileansatellites’ after the Italian scientist Galileowho first discovered them in 1610 (see page169). Ganymede, the largest of all, is 5276km across. It has an icy surface, with darkplains and areas showing a strangely‘grooved’ pattern, as if someone has clawedaway at its surface with a giant fork.

THE SMALLESTMOON

The smallest moon (excludingsmaller fragments of rock and icediscovered circling the largerplanets) is Deimos, whichcompletes its orbit around Marsevery 30 hrs 20 mins. Shaped likea giant potato, it is about 15km long, roughly three-quartersthe length of Manhattan Island,New York City (pictured right). Itis made of a lightweight rockymaterial and covered with a layerof dust. Its largest crater,Voltaire, is 2 km across.

Callisto, another of Jupiter’smoons, is 4820 km across. Forits size it has more craters thanany other planet or moon in theSolar System. The largest crater,Valhalla, is 600 km in diameter(about the size of Poland) andis surrounded by ‘ripples’ about3000 km across.

MOONS, sometimes known as satellites, are smallbodies that circle around the planets of the Solar

System. Earth has one moon, of course, known simplyas the Moon, but the larger planets have many more(Jupiter has 63). The moons are as varied in size andform as the planets themselves and astronomers saythere are two ways in which they came into being.Some are the result of fragments of rock and ice

coming together to form a globe; others are oldasteroids that have been ‘captured’ by a planet’s forceof gravity (see page 10).

All seven largest moons illustrated here are largerthan the dwarf planet Pluto. Mercury, the smallesttrue planet, with a diameter approximately the sameas the distance across Canada and Alaska, is smallerthan both Ganymede and Titan.

Europa, Jupiter’s fourth largestmoon, is 3126 km across. Thesmoothest body in the SolarSystem, the largest ‘hills’ on itsicy crust measure only about300 m high.

Io, Jupiter’s third largest moon,is 3632 km across. For its size,it is the most volcanically activebody in the Solar System. Atany one time, there are sevenor eight eruptions in progress.Only the Earth itself has moreactive volcanoes.

Our own Moon, Earth’s nearestneighbour in space, is 3476 kmacross, the fifth largest moon inthe Solar System. It would take81 Moons to make up a bodythe size of the Earth.

Io’s volcanoes erupt liquid sulphur inplumes which sometimes reach heightsof 280 km (above). The ejected matteris blasted out at 3600 km/h, fasterthan a speeding rifle bullet.

Triton, Neptune’s largest moon,is 2720 km across. Its surface isthe coldest place known in theSolar System: its temperature of-235˚C is low enough to freezeoxygen and nitrogen in the airwe breathe.

GANYMEDE

TITAN

CALLISTO

IO

MOON

EUROPA

TRITON

22 23

TH E LARGES T MOONS Wor l d s o f i c e and rock


SUN

WHAT IS A COMET?Comets have been called ‘dirty snowballs’. The solid core,the nucleus, is a lump of tiny dust particles held togetherby frozen gases and water-ice. When warmed by the Sun,the ices melt and the gas and dust escape to form a largecloud known as the coma. Close to the Sun, material fromthe Sun and sunlight hit the coma and make two tails: astraight gas tail, and a broader, curved dust tail.

Gas and dust escapingComa

Nucleus

Dust tail

Gas tail

9 Feb19

86clo

sest

toSu

n

13 Mar 1986 encounter with Giotto

Launched in July1985, the Giottospacecraft camewithin 500 km ofthe comet’s nucleusduring March1986.

25

T he b r i gh t e s t s ho r t -pe r i od come t

THE MOST FAMOUS of allcomets is named after the

English astronomer Edmond Halley(1656-1742). He was the first topredict that it would return to thenight skies every 75-76 years.

Halley believed that comets, like theplanets, travelled round the Sun inelliptical orbits (elongated circles). Afterexamining the records of comets that hadappeared in 1531 and 1607, he suggestedthat they, along with a comet he observed inthe skies in 1682, were, in fact, all one and thesame. On each occasion, people saw it passingclose to the Earth on its never-ending journeyaround the Sun. Halley did not live to see hisprediction come true. What we now know asHalley’s Comet was next sighted on ChristmasDay 1758, 75 years after the astronomer hadseen it.

Thousands of comets have been discovered.Those that complete their orbits in less than200 years are called short-period comets.Halley’s Comet is the brightest of these. Thelong-period comets (over 200 years) are oftenmore spectacular, with longer tails. The recordfor the longest tail, measured at 320 millionkilometres, is held by the Great Comet of1843.

A COMETARY JOURNEYHalley’s orbit takes it from just outsideNeptune’s orbit to just within that of Venus. Asit approaches the Sun, it heats up, brightens,and grows a spectacular tail of gas and dust,always pointing away from the Sun. The comettravels away from the Sun tail first. Eventuallyit fades and its tail disappears – until the nexttime it nears the Sun.

Halley’s Comet last approached the Earth in1986, but that year it was far away, and barelyvisible. A remote-controlled spacecraft calledGiotto did, however, successfully photograph itat close range. You can make a note in yourdiaries for Halley’s Comet’s next visit – in theyear 2062!

10 Apr 1986 closest to Earth1 NEPTUNE2 URANUS3 SATURN4 JUPITER5 MARS6 EARTH

7 MERCURY8 VENUS

9 GIOTTO spacecraft

24

HAL L EY ’ S COMET


THE LARGEST LAKESsq km Continent

1 Caspian Sea 371,000 Europe/Asia2 Superior 83,270 North America3 Victoria 68,800 Africa4 Aral Sea 65,500 Asia5 Huron 60,700 North America6 Michigan 58,020 North America7 Tanganyika 32,900 Africa

THE LONGEST RIVERSkm Continent

1 Nile 6670 Africa2 Amazon 6570 South America3 Yangtze 6380 Asia4 Mississippi-Missouri 6020 North America5 Ob-Irtysh 5410 Asia6 Yenisei 5310 Asia7 Huang He (Yellow) 4840 Asia8 Congo 4630 Africa9 Paraná 4500 South America10 Amur 4416 Asia

KEY1 Grand Canyon, Arizona, USA Longest gorge 349 km2 Yellowstone National Park, Wyoming, USA Tallest active geyser 60-115 m3 Manitoulin Island, Lake Huron Largest island in a lake 2786 sq km4 Landscape Arch, Utah, USA Longest natural arch 88 m5 Mammoth Cave, Kentucky, USA Longest cave 560 km6 Bay of Fundy, Canada Greatest tides 14.5 m7 Angel Falls, Venezuela Highest waterfall 979 m8 Lake Titicaca, Peru/Bolivia Highest navigable lake 3811 m9 Amazon Largest river basin 7,045,000 sq km

10 Atacama Desert, Chile Driest place No rain for 400 years11 Ojos de Salado, Chile/Argentina Highest active volcano 6887 m12 Valdivia, Chile Most powerful earthquake (1960)13 Scoresby Sund, Greenland Longest fjord 313 km14 Mid-Oceanic Ridge Longest mountain range 65,000 km15 Sahara Largest desert 8,400,000 sq km16 Al’Aziziyah, Libya Hottest place Highest recorded temperature 58˚C17 Nile Longest river 6670 km18 Great Rift Valley Greatest rift valley 6400 km19 Pripet Marshes, Belarus Largest swamp 46,950 sq km20 Caspian Sea Largest lake 371,000 sq km21 Dead Sea, Israel/Jordan Lowest point on land 400 m below sea level22 Lake Baikal, Russia Deepest lake 1637 m23 Tibet Highest plateau 4875 m24 Cherrapunji, India Wettest place Recorded 26,461 mm in one year (1861)25 Mount Everest, Nepal/Tibet Highest mountain 8848 m26 Ganges/Brahmaputra, India/Bangladesh Largest delta 75,000 sq km27 Marianas Trench Deepest point on Earth 11,032 m28 Indonesia Largest archipelago More than 13,000 islands29 Tambora, Indonesia Greatest volcanic eruption (1815)30 Uluru (Ayers Rock), Australia Largest fully exposed monolith 348 m high 3.1 km long31 Great Barrier Reef, Australia Longest coral reef 2027 km32 Vostok, Antarctica Coldest place Lowest recorded temperature -89.2˚C

OF ALL THE PLANETS in the Solar System,Earth has the most liquid water, its

atmosphere contains the most oxygen and itis the only planet that has any form of life.Without water, life could not have developed,and without plant life there would be nooxygen in the atmosphere. Without oxygen tobreathe, no animals could exist.

The oceans amount to nearly three-quartersof the Earth’s surface. The largest ocean, thePacific, accounts for half that area. More thanone tenth of the land area is covered bypermanent ice, mainly in the giant Antarcticand Greenland icecaps. About a third of theland surface forms the continent of Eurasia(Europe and Asia taken together), the largestland mass.

THE LARGEST ISLANDSsq km

Greenland 2,175,592New Guinea 808,512Borneo 745,565

26 27

Ou r home p l ane tE AR TH RECORD HOLDERS


BENEATHTHE RING OF FIRE

This is a cross-section through thePacific ‘Ring of Fire’. When the seafloor dives under continents, itcreates deep trenches. Some of therocks melt when they reach greatdepths, and rise to the surfacethrough volcanoes.

Mauna Kea, one ofHawaii’s volcanicmountains (3), rises10,203 m from the seafloor to its summit. Itis the highest mountainin the world measuredfrom base to top.

Almost three-quarters of the Earth’s surface iswater. Of this, nearly half forms the giant PacificOcean, which covers an area nearly ten times the

size of Russia, the world’s largest country. This enormousexpanse of water has an average depth of 4188 metres,but in the Marianas Trench the bottom plunges to 11,032metres, the deepest point on Earth.

Most of the Pacific’s sea floor consists of one giganticplate (see page 32). Where it crashes into other plates nextto it, the sea floor is slowly being dragged down into deepocean trenches – like the Marianas Trench. All around thePacific (the name means ‘peaceful’), the Earth is alive withactive volcanoes and repeatedly shaken by violent quakes(see pages 41 and 43). Not for nothing is the Pacificshoreline called the ‘Ring of Fire’.

All the small islands scattered across the Pacific startedout as volcanoes. Erupted lava quickly cools to solid rock,while repeated eruptions build up a volcano’s height until itbreaks the surface of the sea. In the tropical waters of theSouth Pacific, coral reefs grow in the shallows all round anisland coastline. Built by tiny animals that grow theirskeletons outside their bodies, a ring of coral – called anatoll – can be left just peeping above the waves after thevolcanic island it once encircled has sunk back beneath thesea. Some are large enough for people to live on.

29

The world’s largestatoll, Kwajalein (4),is in the MarshallIslands, in thecentral PacificOcean.

ASIA NORTHAMERICA

AUSTRALIA

NEW ZEALAND

P A C I F I CO C E A N

Hawaiian Is.

OceanTrench

Volcano

Risingmeltedrock

T he m igh t y Pa c i f i cT H E GREA T E S T OCEAN

The Earth’s deepest point,the Marianas Trench (1)

Draining away all itswaters would reveal thePacific’s deep oceantrenches, its vast sea-floorplains peppered withvolcanoes, and its steepcontinental slopes.

The deepest area of oceanfloor in the world is a‘plain’ to the east of Japan(2). This area has anaverage depth of 4570 m.

28


HIDDEN BENEATH THE OCEANS is the world’sgreatest mountain range. Called the Mid-Oceanic

Ridge, it starts in the Arctic Ocean and runssouthwards through the Atlantic before bending tothe east, winding through the Indian and PacificOceans. It ends up near the west coast of NorthAmerica after a journey of 65,000 kilometres. Some ofits peaks are 4200 metres high, but only a few breakthe ocean waters as tiny islands. Iceland has growninto a large island as volcanoes have erupted over andover again in the same place.

Beneath the Ridge, liquid rock or magma from thehot interior of the Earth rises towards the surface. Thesea floor bulges upwards and cracks open. The magma,called lava as it bubbles out of the Earth’s crust, seepsinto the faults (long cracks) and pushes the rocksfurther apart. Every year, the faults running down theRidge grows wider by a few centimetres – about thespeed that fingernails grow. Over millions of years theocean floor itself becomes wider and wider.

There are much longer faults cutting right across theRidge at right-angles. These break up the sea floor intogiant blocks, giving the Ridge a zig-zag shape.

The Mid-OceanicRidge forms acontinuous chainpassing through allthe world’s oceans.One branch runs upthe Indian Ocean andmeets the Great RiftValley (see page 34)in the Red Sea.

Deep in the centralvalley that runs thelength of the Mid-Oceanic Ridge, tallchimneys made ofsolidified minerals,called black smokers,blast hot smoke intothe ocean waters.These smokersprovide warmth andfood for weird crabs,worms and fishesfound nowhere elseon Earth.

VOLCANOES UNDER THE SEAUnlike the violent explosions of volcanoes like Santorini (see page40), eruptions along the Ridge are fairly gentle. This is because theliquid rock flows easily. Along the centre of the Ridge runs a riftvalley, a strip of land between two parallel faults (see page 35).Most of the eruptions happen here, where lava finds its way to thesea floor through the faults.

Sometimes a volcano may erupt for long enough to grow andreach the surface, where it forms an island in the ocean. BouvetIsland in the South Atlantic Ocean, the most remote island in theworld – 1700 km from the nearest land – arose in this way.

Have you ever noticed that Africa and SouthAmerica would fit snugly together if youpushed one up against the other? In fact,millions of years ago, they were close

together, both making up part of a singlecontinent. The sea floor opened up betweenthem, and the spreading Mid-Oceanic Ridgepushed them far apart.

30 31

ARCTIC OCEAN

ATLANTICOCEAN

PACIFICOCEAN

INDIANOCEAN

Red Sea

A F R I C A

S O U T HA M E R I C A

A F R I C A

S O U T HA M E R I C A

T he m id-ocean i c r i dgeT H E GREA T E S T MOUNTA IN S


THE HIMALAYA-KARAKORAM range is the greatestcontinental mountain range. It divides China in the

north from Pakistan and India in the south. Nepal andBhutan lie entirely within the Himalayas. The top tensummits, as well as about 90 per cent of the world’s100 highest peaks, are found here. The highest peak ofall (measured from sea level) is Mount Everest, whichlies on the Tibet-Nepal border.

The Himalayas are getting still higher, as the forcesthat built up the mountain chain (see panel, below left)continue to grind on. Tibet, to the north, the world’shighest and largest plateau, with an average height of4875 metres, was pushed up by the same processes.

One day, some millions of years into the future, perhapsanother peak may take Everest’s place as the world’shighest.

As the mountains ‘grow’ they are attacked by wind,rain, frost and ice. These forces of erosion produce thesharp, jagged peaks that make the mountain scenery sospectacular. Eventually, these peaks will be worn downto become low, rounded hills.

The Himalayan glaciers and rivers have cut the world’sdeepest gorges, those of the Kali Gandak (betweenAnnapurna and Dhaulagiri) and the Arun (east ofEverest). Both plunge more than 5 kilometres belowneighbouring summits.

Named after ColonelSir George Everest(1790-1866),Surveyor-General ofIndia, Everest isknown to the Tibetansas Qomolangma andto the Nepaleseas Sagarmatha.

High in the Himalayas,several kilometres above sealevel, fossil seashells can befound. Even on the summit ofEverest itself, there arebands of limestone rock,formed underwater out oftiny marine animals. Thehighest range on Earth wasonce sedimentary beds laiddown under the sea. About30 million years ago, Indiacollided with Asia, the rocksstarted to crumple and werethrust upwards.

32 33

COLLIDING PLATESThe Earth’s outer layer consists ofseveral pieces, great ‘plates’ sliding andbumping around the surface of theglobe. Thirty million years ago, twosuch plates started to collide. TheIndian plate slid – and continues toslide – under the Asian one, forcing itto rise and buckle, creating theHimalayan mountains.

THE WORLD’S HIGHESTMOUNTAINS

metres1 Everest 88482 K2 86113 Kanchenjunga 85864 Lhotse 85165 Makalu 84856 Cho Oyu 81887 Dhaulagiri 81678 Manaslu 81639 Nanga Parbat 812510 Annapurna I 8091

The Everest andLhotse peaks, first andfourth highest abovesea level, form part ofthe same mountainmassif. In thisillustration (right),Everest is in the leftforeground, Lhotse toits right.

B H U T A N

NE

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L

IN

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IA

T I B E T

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A S I A

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T he tower i ng H ima l a ya sT H E H I GHE S T MOUNTA IN S


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34 35

TheBlue

Nile

risesin

thehighlandsof

Ethiopia,inthe

streamsandrivers

feedingLake

Tana.It

carriesmorewater

than

theWhiteNile,

which

itjoinsat

Khartoum

inSudan. Thesource

oftheWhiteNile

(thelongestbranch)liessouthof

theEquatorinBurundi,in

mountains

borderingLake

Tanganyika,the

world’ssecond

deepestlake(greatestdepth

1470

m).From

thereitflows

intoandoutofLakeVictoriaon

itslong

journeytothecoast.

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oftheGreatRiftValleyinEastAfrica

(abo

ve).Itwas

herethat,scientistsbelieve,our

human

ancestorsfirstappeared.

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cross-section(right),is

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centre.Eventually,sea-floor

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And the l onge s t r i v e rT H E GREA T E S T R I F T


THE GRAND CANYON in Arizona is the largest gorgeon Earth. It twists and turns across dry, rocky land

for 349 kilometres. Averaging 16 kilometres in widthand 1.6 kilometres in depth, this vast chasm has beencarved by the savage force of the Colorado River andits tributaries. And the process continues today. On anormal day, the river carries off about half a milliontonnes of sediment (mud and gravel pulled along bythe current). When it is in flood, large boulders areswept downstream.

The Colorado has been at work for millions of years,cutting downwards as the land beneath it has graduallyrisen higher and higher. Over a period of about 5 millionyears, the land has increased in height by more than1200 metres. In the meantime, the Colorado has carvedthrough to rocks buried deep below the ground thatonce formed the lower slopes of ancient mountainsstanding 16,000 metres high – twice the height ofMount Everest.

HISTORY IN THE ROCKSAs near a complete display of the Earth’s history as youare ever likely to see is revealed on the slopes of theGrand Canyon. As the land lay under the sea for hundredsof millions of years, coatings of sediment have been laiddown, one on top of the other like blankets on a bed.Each layer turned to stone, the different types reflectingthe climates and life-forms of their age. The oldest rocksof all in the Grand Canyon, found in thedeepest part of the gorge, are 1.7billion years old.

The Colorado River once flowed gentlyacross the desert (1). Then, between 10 and12 million years ago, the land beneath itbegan to rise (2). It did so only by about0.25 mm a year, but the river kept pacewith it, cutting a deeper channel to preserveits downward course to the sea. Itcarved through differentlayers of rock,

This is a bird’s-eye view of the Grand Canyon,showing the arid terrain and characteristic step-like slopes. The Grand Canyon exists onlybecause the climate has always been extremelydry. (The Colorado River’s water comes from thedistant Rockies.) If there had been more rainfall,most of the softer, upper layers of rock wouldhave been washed away.

some hard, some soft. The soft rock woreaway more easily than the hard,which today stands out asvertical cliff faces (3).

37

A cross-section through theGrand Canyon, showing thedifferent layers of rock.

U S A

ColoradoRiver

An aerial view (below) of theGrand Canyon, and itslocation in Arizona, USA.

Colorado R.

T he spe c t a cu l a r G r and CanyonT H E LARGES T GORGE


TH E DEEP E S T LAKE

Lying in the far east of Russia amidst Siberia’smountains and forests, Lake Baikal, the world’sdeepest lake, is sometimes known as the Blue

Eye of Siberia. By area only the ninth largest lake, itis easily the largest body of fresh water in theworld. It holds one-fifth of the world total – morethan all five of the Great Lakes of North Americaput together! If all the world’s drinking water ranout, Lake Baikal could supply the world’spopulation for a further 40 years.

As many as 336 rivers and streams feed intoBaikal, but because most of the surroundingmountains are extremely hard rock, very littledissolved substances find their way into the water.The lake is crystal clear and very pure. Only in thesouth is there man-made pollution, although thisis still very slight.

In the Olkhon Crevice, the bottom plunges tomore than 1600 metres below the surface. Here,the average depth of the lake floor lies muchdeeper than the shores of the Dead Sea (400metres below sea level), the lowest point on landin the world.

Lake Baikal is probably also the oldest lake inexistence, dating back perhaps 25 million years.It has its own special forms of wildlife –hundreds of kinds of creatures living in its

waters that are not found anywhere else.These include the Baikal seal, which lives

3000 kilometres away from its nearestrelatives on the shores of the

Arctic Ocean.

A GIANT CHASMMillions of years ago, Asia split apart and the floorof the Baikal valley dropped away along a series ofgiant faults, cracks in the Earth’s crust. Thebedrock plunges to a depth of at least 9 km, thedeepest point on any of the continents. For manymillions of years, parts of the lake bottomremained dry, but eventually all of the basinbecame flooded. Mud and gravel have beensettling for at least 16 million years and are nowmore than 7 km thick. The water level has beenslowly rising since a dam was built on the Angara,the only river to flow out of the lake, in 1959.

A CLIMATEOF ITS OWNCrescent-shaped LakeBaikal is about 620 kmlong and about 74 km atits widest. Baikal lies closeto the centre of the Asiancontinent. There areextremely cold winters andhot summers. Theenormous amount of waterin the lake causes thesurrounding area to havemilder winters and coolersummers than other partsof Siberia. Even so, about 3m of ice covers Baikal inwinter.

38 39

Two of Baikal's 1500 uniquespecies: the Baikal seal andthe golomyanka

Deepestpoint1637m

R U S S I A

EMPIRESTATE

BUILDING(to scale)

This is a cross-sectionthrough Baikal at itsdeepest point. Thelighter areas showsediments, the linesunderground faults.The deepest point ofLake Baikal is over fourtimes the height of theEmpire State Buildingin New York!

�

Ba i k a l , b l u e eye o f S i b e r i a


Volcanic eruptions, the most powerfulexplosions on Earth, are incrediblydestructive. During the eruption of

Krakatau in 1883, about 20 cubickilometres of rock (nearly the entireexploded mountain) was blasted high intothe air. The noise of the explosion, thegreatest in modern times, was heard 5000kilometres away in India, China andAustralia. Probably three times as muchwas ejected during the eruption ofSantorini around 1450 BC.

Greater still was the eruption ofTambora, on the island of Sumbawa inIndonesia in 1815, when about 160 cubickilometres was blasted away. Pulverizedrock was hurled at least 50 kilometreshigh into the Earth’s atmosphere. Dustblankets drifted around the globe,shutting off the Sun’s rays and causingtemperatures to drop. The year after theTambora eruption, 1816, was known as‘Eighteen hundred and froze to death’.

All that remains today is a ring of five small islands (5).One day the volcanic islands in the centre of the baymay build up into a new, large volcano.

Santorini, today calledThera, was once a singleMediterranean islanddominated by a dormantvolcano possibly about1600 m high (1). The landwas very fertile and therewas a city with a port. Itwas the time of theMinoan civilization,centred on nearby Crete,and the island’sinhabitants lived in peace.All this was to change in1450 BC.

40 41

Some volcanoes, likeKilauea on Hawaii,throw out lava thatflows freely down themountainside. Theyoften erupt withoutgreat explosions. Othervolcanoes have stiff,pasty lava that hardensquickly. Sometimes aplug of solid lavablocks the pathway tothe surface. Pressure

builds up in the magmachamber beneath thevolcano until the plug isblasted away in a greatexplosion. Suchvolcanoes, includingSantorini, Vesuvius andKrakatau, often shootlarge quantities ofcinders, ash and dusthigh into the air, as wellas erupting streams ofhot lava.

UNDER AVOLCANO

Volcanoes erupt gasesand water as well aslava, ash and dust.

The eruption went on forseveral days. Soon, theever-widening cratercollapsed below sea level.Water flooded in (3),triggering even moregigantic explosions as itwashed over the red-hotlava. Eventually, nearly allof the island of Santoriniwas blasted into the sky(4).

FAMOUS VOLCANICERUPTIONS OF THE PAST

DateSantorini, Greece c. 1450 BC

Vesuvius, Italy AD 79Taupo, New Zealand c. AD 150Tambora, Sumbawa 1815Krakatau, Java 1883Mont Pelée, Martinique 1902Katmai, Alaska 1912Mt. St. Helen’s 1980Nevado del Ruiz, Colombia 1985Mt. Pinatubo, Philippines 1991

(Volcanoes located on map, above left)

Suddenly, Santorini’svolcano blew its top.Violent gasexplosions shot vastquantities of lava, ashand dust high into thesky at the speed ofsound (2). The wholeof the mountaintopwas destroyed inwhat was probablythe greatestexplosion of all time.

TH E GREA T E S T EXP LOS I ON

Katmai

Mt. St.Helen's

Mt. Pelée

Nevadodel Ruiz

Vesuvius

SantoriniMt. Pinatubo

KrakatauTambora

Taupo

A vo l c ano b l ows


ON 22 MAY 1960 a giant fault, some 600 kilometreslong, deep beneath the ground in western South

America suddenly slipped about 20 metres. A vast areaof land in southern Chile was violently shaken fornearly four minutes. In the town of Valdivia, buildings

were reduced to rubble. The ocean floor droppedaway, causing the sea to rush away from theshore, then return in several giant waves,10 metres high, which smashed into the shore

and flung ships far inland. It was the mostpowerful earthquake ever recorded.A smaller tremor about ten minutes earlier had sent

most people rushing into the streets. This saved manylives when the main quake came, although around 5000people were killed. This is a small number whencompared with the most deadly earthquake of recenttimes. A quake which occurred on 28 July 1976 killedabout 750,000 people in Tangshan, China.

The force of earthquakes is often described on theRichter scale: the larger the number, the worse theearthquake. The Chilean earthquake measured 9.5, andthe Tangshan one, 7.8.

SOME GIANT EARTHQUAKESDate

Lisbon, Portugal 1755Concepción, Chile 1835Assam, India 1897San Francisco, USA 1906Valparaiso, Chile 1906Messina, Italy 1908Gansu, China 1920Tokyo, Japan 1923Valdivia, Chile 1960Anchorage, Alaska 1964Guatemala 1976Tangshan, China 1976Mexico City, Mexico 1985Spitak, Armenia 1988

GIANT WAVESSudden movement of the sea floor duringearthquakes creates waves that race across theoceans at about 700 km/h. When they approachland, they rear up to great heights (above). Calledtsunamis, they can result in massive destruction.On 26 December 2004, a tsunami surgedashore in Indonesia, Thailand, Sri Lankaand India. Waves of up to 30 m highcaused devastation and claimedthe lives of 283,000people.

In the Chilean earthquake over 400,000 houses were destroyed inminutes as the ground rocked beneath them. Giant cracks andholes opened up in the surface and split the foundations ofbuildings. Afterwards, Valdivia and a vast area of the surroundingcountryside had sunk by nearly 2 m.

Most major earthquakes occur around the‘Ring of Fire’ (the coastline of the PacificOcean, see page 29). Others happen inplaces where plates (see page 32) arepushing against one another: in centralAsia and around the Mediterranean Sea.

P A C I F I CO C E A N

PACIFICOCEAN

42 43

This is a cross-section ‘model’ of the regionaffected by the 1960 earthquake in Chile.Here, the Pacific Ocean floor is graduallyplunging beneath the South Americancontinent. A sudden jolt (marked by the‘explosion’ on the illustration) sent juddersacross a wide area and resulted in thedevastating earthquake.

Anchorage

LisbonSpitak

MessinaTokyo

San FranciscoGansu Tangshan

AssamGuatemala

Valparaiso

ValdiviaConcepción

Mexico City

T he g rea t Ch i l e an quakeT H E GREA T E S T QUAKE


THE

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som

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are

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ve),which,inthe

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ayreach

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around

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ethem

at160km

/hor

more,andcankeep

hailstonesweighing

asmuchas

500g

suspendedintheair!

Clustersofcumulo-

nimbusclouds

can

produceraging

thunderstormsand

torrentialrain,and

may,insomeparts

oftheworld,spawn

destructivetornadoes.

TRI-STATE

TWISTER

Each

year

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ted

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esis

hitby

abou

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mos

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atin

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25.

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gat

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t10

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sted

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d-a-

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dle

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uri,

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ade

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asa

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ain

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eby

.

InNovem

ber1

970acyclonehitthe

low-lyingGangesdelta

inBangladesh

(abo

ve).Violentw

inds

andsurging

wavesclaimed

thelivesofmaybe

upto

halfamillionpeople.Intermsoflives

lost,

itwas

theworstdisastercausedby

astorm

everrecorded.

44 45

BA

NG

LA

DE

SH

T he dead l y t o rnadoT H E MOS T V I O L EN T S TORM


INDEXAAchernar 6Alpha Centauri 6Altair 6Amazon Basin 26Angel Falls 26Annapurna 1 32Antares 8arch, longest natural 26archipelago, largest 26-27Arcturus 6Arsia Mons 20Arun gorge 33Ascraeus Mons 20asteroids 14-15, 23largest 15Atacama Desert 26atmosphere 18-19, 22, 26, 44atoll 29largest 29Ayers Rock (Uluru) 26-27

BBaikal, Lake 26-27, 38-39Betelgeuse 6, 8black hole 9, 10-11black smokers 30Bouvet Island 30

CCallisto 22-23Canopus 6canyon 36-37largest in Solar System 21largest on Earth 26, 36-37Capella 6carbon dioxide 18, 21Caspian Sea 26-27cave, longest 26Ceres 15Charon 15Cherrapunji 26-27Cho Oyu 32-33clouds 16-17, 18tallest 44Colorado River 36-37coma 25comet 16, 24-25brightest short-period 24longest tail 24constellation 6-7largest 6-7smallest 6coral reef 29longest 26-27crater 19most in Solar System 22Crux 6cumulonimbus 44cyclone see hurricaneCygnus X-1 11

DDead Sea 26-27, 34, 39Deimos 22delta, largest 26-27desert 37largest 26-27Dhaulagiri 32disaster, worst caused by a storm 45dwarf star 9

EEarth 14, 16-17, 23, 25, 26-27coldest place 26-27crust 21deepest point 28-29driest place 26greatest cleft 35highest point 29, 32-33hottest place 26-27largest land mass 26largest ocean 26, 28

lowest point 34lowest point on land 26-27plate movements 21, 29, 31, 32wettest place 26-27earthquake 42-43Chilean 42-43greatest-ever recorded 26, 43Tangshan 43energy 9, 10-11, 12Eta Carinae 6Europa 23Everest, Mount 20-21, 26-27, 32-33explosion, greatest 9, 40-41

Ffaults 30, 35, 38, 43fjord, longest 26-27Fundy, Bay of 26

Ggalaxy 6-7, 11nearest 6Galileo Galilei 22Ganges delta 26-27, 45Ganymede 22gas giants 15geyser, tallest active 26Giotto spacecraft 24-25gorgedeepest 33,largest and longest 26, 36-37Grand Canyon 26, 36-37gravity 10-11, 16, 23Great Barrier Reef 26-27Great Red Spot 16-17Great Rift Valley 26-27, 34-35Greenland 27

HHadar 6hailstones 44Halley, Edmond 24Halley’s Comet 24-25Hawaiian Islands 21, 29helium 12, 15Himalayas 20-21, 32-33hot spot 20-21hurricane 17, 44-45Hydra 6-7hydrogen 12, 15, 16

Iice 21, 26Indonesia 26-27, 41Io 23islandlargest 27largest in a lake 26most remote 30

JJupiter 14-15, 16-17moons 22-23

KK2 32Kali Gandak gorge 33Kanchenjunga 32-33Karakoram 32-33Krakatau 40-41Kwajalein Atoll 29

Llake 38-39deepest 27, 38-39highest navigable 26largest 26-27oldest 39Landscape Arch 26lava 29, 30, 35, 40Lhotse 32-33light 10speed of 7, 10light-year 7

lightning 44-45

MM31 galaxy 6M33 galaxy 6Magellan spacecraft 18-19Magellanic Cloud, Large 6magnetic field 12Makalu 32-33Mammoth Cave 26Manaslu 32-33Manitoulin Island 26Marianas Trench 26-27, 28-29Mars 14, 20-21, 22Mauna Kea 29Maxwell Montes 18Mercury 14, 18, 23meteoroid 19Mid-Oceanic Ridge 26-27, 30-31, 34-35Milky Way Galaxy 11Moon 23moons 22-23largest 22-23smallest 22-23mountain 32-33highest in Solar System 20-21highest on Earth 29, 32-33mountain rangehighest 32-33longest 26-27, 30-31Mu Cephei 6, 8

NNanga Parbat 32Neptune 15, 23neutron star 9, 10Nevado del Ruiz 41Nile, River 26-27, 34-35nuclear fusion 12nuclear reaction 8, 12

Oocean 28-29, 30-31deepest area 28largest 26, 28-29trench 28-29Ojos del Salado 26Olympus Mons 18, 20-21

PPacific Ocean 26, 28-29Pavonis Mons 20Pelée, Mont 41photosphere 12Pinatubo, Mount 41planet 8, 10, 14-25closest to Earth 14, 18closest to Sun 14coldest 15farthest from Sun 15first discovered using telescope 15hottest 14, 18-19largest 12-13, 14-15, 16-17largest rings 15most moons 15quickest orbit of Sun 14shortest day 16smallest 15plateau, highest 26-27, 33Pluto 15, 23Princeton Plasma Physics Laboratory 12Pripet Marshes 26-27Procyon 6prominence 12protostar 8Proxima Centauri 6

QQomolangma 33quasar 7, 10-11

RRas Algethi 8red giant star 9

Red Sea 34-35rift valley, greatest 26-27, 34-35Rigel 6Rigil Kent 6Ring of Fire 29, 42river 34-35, 36-37largest basin 26longest 26-27, 34-35rocks 36-37

SSagarmatha 33Sagittarius Dwarf Galaxy 6Sahara 26-27sand dunes, largest area in SolarSystem 21Santorini 40-41Saturn 14-15, 16moons 22Scoresby Sund 26-27sediments 36, 38Siberia 39Sirius 6Solar System 8, 12, 14-17, 22-23, 24-25coldest place 23fastest winds 16highest mountain in 14, 20-21hottest place 12St. Helen’s, Mount 41star 8-9, 10-11, 12-13brightest 6largest 6, 8-9life and death of 8-9most massive 6nearest 6, 12-13smallest 9storms, most powerful 44-45Sun 8-9, 10, 12-13, 14-15, 16, 24-25eclipse of 13sunspot 12-13largest 13supergiant star 8-9, 11supernova 9, 10swamp, largest 27

TTambora 41Taupo 41Tharsis Ridge 20thunderstorm 44Tibet 26-27, 33tides, greatest 26Titan 22Titicaca, Lake 26tornado 44-45Tri-State Tornado 45Triton 23tsunamis 42

Uuniversedensest object in 10-11farthest visible object in 6most distant object in 11Uranus 14-15

VValdivia 26, 42-43Vega 6Venus 14, 18-19Vesuvius 40-41volcanic eruption 21, 30, 40-41greatest 26-27, 41volcano 18, 20-21, 23, 29, 30, 34-35, 40-41highest active 26VV Cephei B 8

Wwaterfall, highest 26waves, highest 42windsfastest in Solar System 16fastest on Earth 44

46


CONTENTS RECORD BREAKERS Earth and Universe · 2016-10-27 · launched from Earth must go faster...

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