Is there life on Mars?

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Is there life on Mars?

IS THERE LIFE ON MARS?

Fasten your seatbelts, space travellers! This book will take you on a journey through the solar system. Our mission is to understand what it takes for life to exist – both here, on Earth and on different planets.

Is there life on Mars?

An information book collins.co.uk/collinsbigcat

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Is there life on Mars?

Contents 1 Is there anybody out there?

2

2 The solar system

6

3 The conditions for life

10

4 Heat and sunshine

12

5 Air

16

6 Water

18

7 Does Mars have the conditions for life?

20

8 Is Mars too cold?

24

9 Lighter than air

28

10 Is Mars too dry?

32

11 Other evidence of life

36

12 UFOs and beyond

40

Glossary

44

Index

45

The conditions for life

46

Written by Inbali Iserles

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1 Is there anybody out there?

Have you ever gazed at the sky at night and wondered if we are alone in the universe?

Is there life on distant planets? If we look through a telescope into outer space, is someone looking back at us?

People have been searching for answers to these kinds of questions for thousands of years.

2

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What is an alien?

The word “alien” means a living creature from another planet.

Picture an alien in your mind. What does it look like? Is it like a small, green human?

Is it colourful and blobby? Or spotted with a long tail? Is it whizzing around on a spaceship, a “UFO” (or “unidentified flying object”)?

Aliens are popular characters in books, films and TV shows. The most common aliens that appear in stories are “Martians” – creatures who live on the planet Mars.

But do they really exist?

3

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Life on Earth Being “alive” is what makes animals and plants different from stuff like rocks and water. Living things grow, reproduce and use energy.

It is thought that life first appeared on Earth about 3.5 billion years ago. Every type of life that followed – all trees, mushrooms, birds, lizards and even humans – can be traced back to these earliest life forms.

13.8 billion years ago: universe created in big bang

3.5 billion years ago: simple life forms

4.5 billion years ago: our solar system formed

230 million years ago: dinosaurs

800 million years ago: earliest animals

4

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Fasten your seatbelts, space travellers! We are about to set off on a journey through the solar system.

Our mission is to understand what it takes for life to exist – both here, on Earth and on different planets.

Lift off in three, two, one!

7 million years ago: shared human and chimpanzee ancestors

65 million years ago: dinosaur extinction

2 million years ago: earliest humans

4 million years ago: oldest human ancestors

300,000 years ago: modern humans

5

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2 The solar system Our solar system is made up of the Sun and eight planets. The closest planet to the Sun is Mercury. The daytime temperature there can go over 400 degrees Celsius. That’s four times hotter than boiling water!

After Mercury comes Venus, Earth and Mars. Then it’s the asteroid belt, where over a million huge rocks travel around the Sun. On the far side of the asteroid belt are the “gas giants”: Jupiter, Saturn, Uranus and Neptune.

the solar system Sun

Mercury

Venus

Earth

Mars

The Sun is the largest object in our solar system.

asteroid belt

6

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FACT! Orbiting the Sun All the planets in the solar system travel around the Sun. Mercury takes only 88 days to complete its orbit. Earth’s orbit takes 365 days (or a year). The furthest planet in our solar system is the huge and icy Neptune.

It takes an incredible 165 years to orbit the Sun!

Jupiter

Saturn

Uranus

Neptune

7

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What is the Sun? The Sun is a star at the centre of our solar system.

Although larger stars exist in faraway galaxies, the Sun is still absolutely gigantic.

Earth

FACT! Giant Sun Earth could fit into the Sun over one million times!

8

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Plus

Lime Plus Band 11+

Is there life on Mars?

IS THERE LIFE ON MARS?

Fasten your seatbelts, space travellers! This book will take you on a journey through the solar system. Our mission is to understand what it takes for life to exist – both here, on Earth and on different planets.

Is there life on Mars?

An information book collins.co.uk/collinsbigcat

85566_Cover.indd 1

Inbali Iserles 27/10/2021 12:43