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BREATHTAKING FEATURES OCEA N S E X T R E M E S LARGE EXPANSE OF WATER N A T U R A L D I S A S T E RS RY VE Our Planet Copyright © 2010 Top That! Publishing plc Tide Mill Way, Woodbridge, Suffolk, IP12 1AP, UK www.topthatpublishing.com Top That! is a trademark of Top That! Publishing plc All rights reserved
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NATURAL WONDERSBREATHTAKING FEATURES
OCEA
NS
VERY
LARG
EEX
PANS
EOF
WAT
ER
EXTREM
ES
NATURAL
DISASTERS
ATMOSPHEREGASES THAT SURROUND EARTH
Copyright © 2010 Top That! Publishing plcTide Mill Way, Woodbridge, Suffolk, IP12 1AP, UK
www.topthatpublishing.comTop That! is a trademark of Top That! Publishing plc
All rights reserved
Our Planet
Origins of EarthPages 4–5
The SunPages 6–8
The AtmospherePages 9–11
WaterPages12–13
MountainsPages 14–15
RiversPages 16–17
Electric SkiesPages 18–20
EarthquakesPages 21–23
VolcanoesPages 24–25
WindPages 26–28
Snow and IcePages 32–33
CONTENTS
2
RainPages 29–31
AfricaPages 36–38
AustralasiaPages 45–47
CONTENTS
Natural WondersPages 59–61
South AmericaPages 53–55
Sun and MoonPages 56–58
Extreme HeatPages 34–35
AsiaPages 39–41
North AmericaPages 50–52
AntarcticaPages 42–44
EuropePages 48–49
3
Earth was formed around 4.7 billion years ago
Dinosaurs arrived around 250 million years ago
Humans (Homo Sapiens) arrived around 250,000 years ago
Imagine ‘time’ as represented by the distance betweenyour outstretched arms. The universe was formed onyour longest left-hand finger. One-cell lifeforms beganbetween your wrist and your elbow. Dinosaurs did notappear until you reach your right hand. Humansarrived on the fingernail of your longest right-hand finger!
Our planet is one of eight planets circling the Sun. Our whole solar system isjust one of many millions in a vast universe.
ORIGINS OF EARTH
How old is Earth Was there life on Earthfrom the beginning
One theory is thatEarth formed from a gigantic cloud ofspinning gas anddust. Here’s what isthought to have happened.
Definitely not! At first, Earth’s surface was far too hotto support any form of life. Gradually, however, itcooled down so that a thin crust formed round the outside. It remained boiling hot inside – and is still thesame today!
The oldest microfossil found so far is 3,500 millionyears old. Life began about 1,000 million years afterEarth was formed. Scientists tend to date the age ofrocks to give us clues to Earth’s age, working on a‘calendar’ that spans millions of years.
When did life on Earth start
How was Earth formed
A floating cloud ofgas and dust wassent spinning byan exploding star.
Gases formedinside the spinningcloud to form anew star – our Sun.
The remainingdust continued tospin around the Sun,forming the planets.
The planetscollided and weresent spinning intotheir orbits.
5
THE CRUSTThis section is thickest at theHimalayas (70 kilometres/43 miles) and thinnest beneaththe oceans(5 kilometres/3 miles).
INNER COREThis section is asolid ball composedmainly of iron. It isthe hottest part, at4,300°C (7,772°F)!
OUTER COREThis is an incredibly hot3,700°C (6,692°F). This,plus the inner core, islarger than theplanet Mars!
MANTLEThis section containsmore iron than thecrust and is like meltedplastic the nearer itgets to the core.
Earth is made up of layers.We live on the crust.
The distance aroundEarth from top to bottom and round the middle is almostthe same – 40,000kilometres (24,860miles) – it’s slightly different because the world isn’t exactly round.
FACT BYTES
6
Our Sun was formed billions of years ago. All the planets in the solar systemorbit around the sun, and it provides warmth and light to Earth. Despite beingvery old, both the surface of the Sun and its interior are hotbeds of activity.
How big is the Sun
The Sun is truly massive. To give you some idea, it is 110 times wider than Earth and you could fitEarth into the Sun about 1,300,000 times!Interestingly, the temperature of the Sun’s surface is about the same as at Earth’s core.
THE SUN
As you would expect from such a gigantic fireball, thetemperature is blazing hot. The centre of the Sun isestimated to be around 15 million degrees centigrade(59 million degrees fahrenheit). That’s hot enough tomelt absolutely anything instantly!
How hot is the Sun
The Sun started as a rotating cloud of gas and dust.This rotation flattened the cloud and pressed the dusttogether in the centre so that it became a larger lump.Once enough matter had been pressed together, thelump became larger, very dense (squashed) and very
hot! Once the heat reached a certain point, nuclearreactions began and the star, our Sun, was born! Thenuclear reactions at the Sun’s centre create enoughpressure to prevent the Sun collapsing.
What is the Sun made of and how does it work
The Sun started as acloud of dust and gas andformed a large ball.
After the Sun was formed,dust around it clumpedtogether, forming planets.
Earth relies on the Sun’sheat and light to sustainlife on its surface.
From the earliest times,humans have realisedthe need for the Sun tosustain life. The Aztecsof ancient Mexico, theIncas of Peru and theancient Egyptians allworshipped the Sun asa god.
FACT BYTES
7
SOLAR FLARE
CORONA
CONVECTIVEZONE
RADIATIVE ZONE
CORE
An artist’s impressionof a cross-section of
the Sun
Only a small partof the Sun’s totalenergy reachesEarth, but it isenough to makeeverything liveand grow.
FACT BYTES
Nothing! A sun is a burning star that gives out light.So, by looking at the night sky, you can see that theSun is not alone in being a star. All those twinklingpinpoints of light are other stars in other galaxies,giving out heat and light just as our Sun does!
What is the difference betweena sun and a star
How long will our Sun last
The Sun will burn out eventually, but don’t worry – it’snot going to happen just yet. Scientists estimate thatthe Sun will have used up all its energy in about7,000 million years time!
What are all those black spots
Sunspots are dark patches on the surface of the Sun.They appear black because these areas are not as hotas the gas surrounding them. Some sunspots arearound 150 times larger than Earth! Bright clouds ofhelium, called faculae, occur above the areas wheresunspots are about to form. Solar flares are brightloops of hot gas emerging from the areas of the Sunwhere sunspots are present. A flare can last from afew seconds to several hours.
WARNING
Don’t try looking for sunspots or solar flares. Youshould never look at the Sun through a telescope orwith the naked eye. It can damage your eyesight andeven make you go blind.
A sunspot on the surface of the Sun
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