Is There Life on Other Planets?

Is There Life on Other Planets?

By Kate Wilkinson-Brindle
Illustrated by Jason Henderson

Mercury Venus Earth Mars Saturn UranusNeptune
Jupiter

The Solar System

This is the solar system. Can you see Earth? Earth has a
breathable atmosphere and liquid water on its surface, is what
support life on our planet. Is there life on other planets? Let’s
explore the other planets and find out if we are the only living
things in the solar system!

Mercury

Mercury is the smallest planet in our solar
system. It’s only a little larger than Earth’s
Moon. It spins on its axis so slowly that
one day on Mercury is as long as 59 Earth
days! Mercury is too small to have a proper
atmosphere like Earth because its gravity is too
weak. Instead it has a very thin layer of hydrogen, helium
and other gases surrounding it. This is called an exosphere.
The temperatures on Mercury range from 430 °C in the day
to −180 °C at night. The lack of atmosphere and the extreme
temperatures make it very unlikely that any sort of life could
survive on Mercury.

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Venus

Venus is a terrestrial planet that is a similar size to Earth.
Venus rotates extremely slowly on its axis. This means that
one day on Venus is equal to 243 Earth days. However, Venus
only takes 225 Earth days to orbit the Sun, so on Venus, a
day is longer than a year! Water may have once been present
on Venus, but life as we know it couldn’t survive there; the
planet has clouds made of acid and temperatures of up
to 465 °C!

Venus spins in the opposite
direction to all of the other
planets, so the Sun rises in
the west and sets in the east.

Mars

Mars is half the size of Earth. It has two moons
called Phobos and Deimos. Like Earth, Mars has
ice covering its north and south poles. The surface of
Mars contains rusty iron that gives it a red, dusty appearance.
Mars seems to have had plenty of liquid water on it in the
past, but the water on Mars today is mainly found as ice.
An atmosphere of carbon dioxide, nitrogen and oxygen, and
temperatures ranging from 20 °C to −153 °C, make Mars the
most likely planet on which we could find life.
However, there is currently no evidence that
life exists on the red planet.

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The Gas Giants

Jupiter
Jupiter is the largest planet in our solar system. Because
the planet is made of hydrogen, helium and other gases,
it’s unlikely that Jupiter supports any kind of life. However,
scientists have found evidence that one of its 79 moons,
Europa, has a large ocean underneath its icy crust, which
means that life could possibly be found there one day!

Saturn
Saturn is made up of swirling gases, and
has beautiful, complex rings made of
chunks of rock and ice. Several
spacecraft have flown past Saturn
to take photographs, and they
have found no evidence of life.

The Ice Giants

Uranus
Cold and windy, Uranus is four times larger
than Earth. It is made mostly of icy water,
methane and ammonia. With its clouds of
poisonous, sulphurous gases that smell like rotten
eggs, Uranus is unlikely to host life as we know it.

Neptune
Neptune is the farthest planet from the Sun in our solar
system. As a result, it is dark, cold and extremely windy.
Clouds of frozen methane gas blow across Neptune at
speeds of over 2,000 kilometres an hour. Neptune is
inhospitable to life.

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