Open your eyes to a world of discovery
Eye Wonder
Eye Wonder
First American Edition, 2001
01 02 03 04 05 10 9 8 7 6 5 4 3 2 1
Published in the United States by
DK Publishing, Inc.
95 Madison Avenue
New York, New York 10016
Copyright © 2001 Dorling Kindersley Limited
All rights reserved under International and Pan-American Copyright
Conventions. No part of this publication may be reproduced, stored
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without the prior written permission of the copyright owner.
Published in Great Britain by Dorling Kindersley Limited.
Library of Congress Cataloging-in-Publication Data
Holland, Simon, 1955–
Space / by Simon Holland.— 1st American ed.
p. cm. -- (Eye Wonder)
Includes index.
ISBN 0-7894-7854-4 -- ISBN 0-7894-8182-0 (lib. bdg.)
1. Astronomy--Juvenile literature.
[1. Outer Space. 2. Astronomy.] I. Title. II. Series.
QB46 .H73 2001
520--dc21 2001017277
ISBN 0-7894-7854-4
Color reproduction by Colourscan, Singapore
Printed and bound in Italy by L.E.G.O.
See our complete
catalog at
www.dk.com
Written and edited by Simon Holland
Designed by Tanya Tween, Claire Penny,
and Tory Gordon-Harris
Publishing manager Mary Ling
Managing art editor Rachael Foster
US editors Gary Werner and Margaret Parrish
Jacket design Chris Drew
Picture researcher Jo Haddon
Production Kate Oliver
DTP designer Almudena Díaz
Space consultant Carole Stott
4-5
Staring into space
6-7
Our place in space
8-9
A closer look
10-11
Journey to the Moon
12-13
Earth’s moon
14-15
The Sun
16-17
Family of the Sun
18-19
Mercury and friends
20-21
Sister Venus
22-23
The Red Planet
24-25
A rocky racetrack
26-27
King of the planets
LONDON, NEW YORK, SYDNEY, DELHI, PARIS,
MUNICH, and JOHANNESBURG
Contents
28-29
Planet of the rings
30-31
Distant twins
32-33
Pluto and the comets
34-35
Secrets of the stars
36-37
The Milky Way
38-39
About the universe
40-41
Liftoff
42-43
Life in space
44-45
Our future in space
46-47
Space glossary
48
Index and
acknowledgments
IT’S QUIET UP THERE...
When something makes a
sound, the noise spreads out into
the air around our ears. Our
world is full of air, which is why
we can hear lots of sounds – but
there is no air in space. Even if
we could take an
entire orchestra
into space and
sit next to it,
we would not
hear any of
the music – not
even the drums!
4
Our nearest neighbor
After the Sun has gone down,
the Moon is the brightest thing
in the sky. The Moon is the
closest object to us in space,
much closer to us than the
Sun. Although it looks quite
big in our sky, it is many times
smaller than the Sun.
What is space?
Beyond our world there
are many other objects. Some
are colorful and massive, others
distant and mysterious, but all of them
are moving. In between, there are enormous,
empty gaps that we call
space. We also use the
word “space” to refer
to everything that lies
outside our own world.
Staring into space is something
people do all the time. On a clear
night, we are able to see bright objects
in the sky. These objects are in space.
Things in space look like tiny dots to
us, because they are so far away, but
most are actually extremely large.
Staring
into space
5
Why is it so dark in space?
Light is something that travels through space. Day and night, all
the light we receive comes from the stars. We can only see light
when it hits an object and bounces off it. Our planet (Earth)
is nice and bright because light can bounce off tiny specks,
called “particles,” in the atmosphere around it (see page 7).
Space is empty, so there are no particles for the light to hit.
Gazing at stars
We live on a planet, and
most of the bright dots in our
night sky are stars. The nearest star
to us is the big, yellow-orange ball we can see
during the day – the Sun. It is much bigger than a
planet like ours. The Sun looks enormous in our sky
because it is so much closer to us than other stars.
Up in space there
are gigantic areas
of nothingness.
This satellite
is an object
in space that
is lit up by light
from the Sun.
6
Nearly three
quarters of the
Earth’s surface is
covered in water.
Why is the sky blue?
Sunlight is made up of different colors. When the light reaches Earth
its different colors bounce off tiny particles of dust and water vapor in
the atmosphere. Because of this, the colors get scattered all around
in the sky. The blue parts of the light are scattered more than the
others, which is why our sky looks blue during the day.
Planet Earth turns and travels
in space, but here on the ground
we cannot feel it moving.
There is a giant ball of
solid metal at the center
of our planet. This is the
Earth’s “core.”
Earth spins around as
it travels. It takes just
under 23 hours and
56 minutes for it to
make one full turn.
7
Our place in space
AN INVISIBLE FORCE
If somebody dropped an object, it would fall
down toward their feet. This is because
everything on Earth is held in place by a
special, invisible force called gravity.
Earth’s gravity pulls everything down
toward the ground – so without this force
we would all float up into the sky, and our
oceans would spill into space! Earth is not
the only place in space
where this force is at
work – gravity exists
everywhere in
the universe.
Lively planet
Earth is the only planet we know of
where living things can survive. Many
different kinds of plants and animals
live on this planet – so many, in fact, that
nobody has counted them all. Plants and
animals need water and a gas called oxygen
to live. There is plenty of both on planet Earth.
Our home in space is called Earth. It is a
planet, a huge world that moves around
in space. Planet Earth is largely made of
rock, but most of the surface is covered
in water – our seas and oceans.
Special blanket
Our planet is covered in a thick layer of gases called
the atmosphere. We cannot feel this layer, but it
contains the air that we breathe and the clouds that
give us rain. It is important because it lets in all the
light and heat we need from the Sun, but keeps out all
the harmful things in the Sun’s rays. The outer part of
our atmosphere is where Earth ends and space begins…
Luckily, the conditions on Earth
are just right for living things.
It is easy for us to see familiar objects in the
night sky, such as the stars – but space is a
big place, so there is always more to discover.
People practice astronomy to get a closer,
clearer look at things in space, or simply to
try to see as far away as possible. Exciting
new finds are being made all the time.
A closer look The Great Bear
The Centaur
The biggest and most
powerful telescopes
are kept in large
buildings called
observatories.
The astronomer’s tool
There is a special instrument,
called a telescope, which
helps astronomers to see
distant objects in space.
It works like a very strong
magnifying glass, making
objects look much bigger
and clearer to the eye.
Telescopes come in
different strengths
and sizes.
Eyes in the sky
Earth has a thick atmosphere, which
gets in the way when astronomers
are trying to see objects more clearly.
To get a better view of things, some
large telescopes are based high up on
mountains – where the atmosphere is
thinner and clearer – or even in space
(on board specially made satellites).
Space patterns
The first astronomers made
patterns out of the stars in
our sky – like connect-the-dot
pictures – to help them tell the
stars apart. These patterns
are called constellations.
Each one has its own name.
The Hubble Space Telescope (HST)
WOODEN WONDERS
The first telescopes were
made around 400 years
ago. They were not as
powerful and accurate
as today’s equipment,
but helped
astronomers to make
important discoveries.
In 1781, an English astronomer
called William Herschel discovered
the planet Uranus using a wooden
telescope. Today, astronomers do
not even have to look into the sky
themselves, because their telescopes
have special computers that can
collect the information for them.
Antenna
Dish
Radio telescopes
Some telescopes work by tuning in to radio
waves from space. The large dish picks up the
radio waves and focuses them onto the antenna,
which then turns them into electrical signals.
A computer uses these signals
to build up pictures of
objects in space.
Journey to the Moon
Apart from planet Earth, the Moon is the only place in space
where human beings have walked. There have been six successful
missions to put people on the Moon, all between 1969 and 1972.
A total of 12 astronauts have explored the surface.
Rocket ride
In 1969, three American astronauts set off from Earth in
a space capsule called Apollo 11. The capsule was launched
into space by Saturn V, a powerful rocket. In space, the
Apollo craft separated from the rocket and made its
way toward the Moon. When it reached the Moon,
a special lunar landing module, called the
Eagle, dropped down onto
the surface with two
astronauts inside.
10
A view seen by few
The crew of the Apollo 8 spacecraft were the first
people to see an “Earthrise” – Earth rising above the
lunar landscape (above) – when they flew around
the Moon in 1968. Earth’s daytime side is lit up by
the Sun, while its nighttime side is lost in darkness.
A rocket journey
to the Moon and
back takes about
six days.
This is what our
planet looks like
from the
Moon.
Launch of the Saturn V rocket, July 1969.
With no wind
to remove them,
an astronaut’s
footprints could
stay in the
Moon’s soil
for millions
of years.
Moon walking
The Moon’s gravity is much weaker
than Earth’s. This means that objects
on the Moon are not pulled down
toward the ground as strongly.
This makes walking difficult. In
fact, the easiest way to get about is
by hopping like a kangaroo! A Moon
astronaut could jump almost six
times as high as a person on Earth.
Back with a splash
The Apollo 11 command module, Columbia,
made a safe return to Earth by falling into the
Pacific Ocean. This is called a splashdown.
After the module had come back into Earth’s
atmosphere, three parachutes opened out to
slow it down on its way toward the ocean.
Moon machine
The first men to walk on the Moon
were Neil Armstrong and Edwin
“Buzz” Aldrin. This is the Eagle craft
which took them down onto the
surface – and later, back to Apollo.
Astronauts on the
Moon can only talk
to each other by using
the special radios
inside their helmets.
11
The backpack
contains a
supply of air.
The lower
part of the craft was
left behind when the
Eagle left the Moon.
A special visor protects
the astronaut’s eyes from
the Sun’s bright rays.
Armstrong and Aldrin spent nearly a whole day on the surface. Meanwhile,
Michael Collins orbited the Moon inside the Apollo 11 command module.
The Moon is the largest, brightest object
in our night sky. But, unlike the Sun,
it has no light of its own to give out.
It looks so bright because its surface
is lit up by the Sun. There is no air,
weather, or life of
any kind on
the Moon.
Earth’s moon
This picture
of the Moon
was taken by the
Apollo 11 spacecraft
as it flew back to Earth.
These dark
patches are
called “seas,”
but they do not
contain any water.
Near side
Moving around
The Moon is always traveling
in space – on a path around our
planet. This journey is called an
orbit. As it travels, it also turns
like a spinning top. It
spins exactly once
during each orbit
of the Earth.
12
Our moon is like a nighttime lantern
in
the
sky.
This is where
the Eagle
module
landed.
Data zone
13
Crescent First Quarter Full MoonGibbous
Far side
A secret side
The same side of the Moon faces our planet
all the time. This means that there
is one side that we can never
see from Earth. The far
side (right) is very
different from the
near side (left).
There are fewer
dark “seas” but
many more
craters.
When it faces the
Sun, the Moon’s
rocky surface can
get too scorching
hot to touch.
These bowl-shaped
hollows on the surface
are called craters.
Very old ice
The Lunar Prospector
space probe (above)
discovered some frozen
water near to the Moon’s
north and south poles.
This ice is probably left
over from comets that
crashed into the Moon’s
surface a long time ago.
Does the Moon change shape?
As the Moon moves around the Earth, we see different
amounts of its sunlit side. This is why the Moon seems to
change shape. These changes are called the phases of the
Moon. The first phase is the new moon, when it cannot be
seen at all. Then we see the crescent, the first quarter,
the gibbous, and finally the full moon.
13
New Moon
• The Moon travels
around the Earth in just
over 27 days.
• A Russian space
probe called Luna 3
was the first
spacecraft to
take pictures of
the far side
of the Moon.
14
The Sun is the nearest star to Earth. Like all stars,
it is an enormous ball of burning, scorching hot
gas. It is a fiery monster, but the Sun is what
makes all life on Earth possible.
Sunset light show
It is dangerous to look directly
into the Sun because it is so bright.
One way of enjoying our local star more
safely is by watching the sky at sunset. As the
Sun sets, we can see more of the colors in its
light – and the beautiful patterns they form.
The Sun
This probe has been
exploring the unknown
regions of space
above the Sun’s
north and
south poles.
The Ulysses
space probe
Fantastic
fireworks
The Sun’s center,
or “core,” is like an
enormous furnace
where gases burn.
At the surface, gas
leaps up in bright bursts
called solar flares. Often,
these blasts of really hot gas
arch up high above the surface
to form “solar prominences” –
great big, fiery loops.
A loop-shaped
prominence
leaping out.
15
An eclipse of the Sun
A solar eclipse takes place when the Moon passes
between the Sun and Earth. When this happens, the
Moon stops some of the Sun’s light from reaching us
and casts a shadow on parts of our planet. At these
places on Earth, day turns to night for a short time.
It takes eight minutes for
the Sun’s light to reach
planet Earth.
ANCIENT
ASTRONAUTS
There is a Greek myth about an
inventor called Daedalus who
made wings for himself and
his son, Icarus, out of
feathers and beeswax.
When Icarus used
the wings he flew
too close to the
Sun. The wax
melted and he
fell into the sea.
The center of
the Sun is like a
giant bomb that
never stops
exploding.
Storms on the surface send
“blastwaves” into space.
These can damage satellites,
and even cause power
outages on Earth!
16
The Sun is at the center of a neighborhood
of planets called the solar system. Earth is
one of nine planets that each make a special
journey, called an orbit, around the Sun.
Family of the Sun
Sun
Mercury Venus Earth Mars
Jupiter
Asteroid
Belt
Sun and planets not to scale
All the planets travel in the same direction around the Sun
The “inner planets” ar
e made of rock
s and meta
ls
Each plane
t spins on
a tilt
Jupiter takes
nearly 12 Earth years
to orbit the Sun.
A planetary year
A planet’s year is the
time it takes to make
one full journey (orbit)
around the Sun. The
further a planet is from
the Sun, the longer its
orbit will be. Planets
with the biggest orbits
have the longest years.
17
Saturn
Uranus
Neptune
PlutoPluto has the
longest path
around the Sun.
...but at different speeds.
...the “
outer
plane
ts” a
re fa
t, ga
ssy
gia
nt
s.
...but so
me tilt
more
than
other
s.
Saturn has at
least 22 moons,
and astronomers are
always looking for more.
Planets and moons
A moon is a large, rocky
object in space that orbits
a planet. Moons come in a
variety of sizes, but most look
like small planets. Apart
from Mercury and Venus, all
the planets have one or more
moons. Saturn and Uranus
have more than 20 each!
A Neptune
year is the
same as 165
Earth years.
• The planets of the solar
system are held in this
arrangement by gravity. The
Sun has the strongest gravity of
all – so all the planets are forced
to keep to their paths around it.
Gravity is also what keeps a
moon in orbit around its planet.
• Mercury, Venus, Earth, and
Mars make up a group called
the “inner planets.”
• Jupiter, Saturn, Uranus,
Neptune, and Pluto are the
“outer planets.”
• The planets nearest to the
Sun travel much faster than
those that are farther away.
Data zone
SPINNING TOPS
All the planets spin, or “rotate,” as they travel in
their orbits around the Sun – but each one
spins at a different speed. Even though it
is the largest planet in the solar system,
Jupiter turns the fastest. It makes one
full rotation in less than 10 hours.
Earth rotates once every 23.93 hours.
This is Callisto, Jupiter’s
second largest moon. It is the
same size as planet Mercury.
18
If people moved
to Mercury, they
would be four times
as many years old!
Hot planet, cold planet...
Mercury is scorching hot during the day, when
temperatures are four or five times greater than the
hottest places on Earth. But its thin atmosphere is
not able to hold on to any heat from the Sun – so
at night, Mercury quickly plunges into a deep freeze!
19
Too hot for humans
Venus has a thick
atmosphere that hides
the surface from view.
It works like an enormous
winter blanket, trapping
all the heat from the Sun.
Because of this, Venus is
the hottest planet in the
solar system.
SPACE RACER
It takes just 88 Earth days for Mercury to
complete its journey around the Sun – so it has
the shortest year in the solar system. It is also
the fastest-moving planet, which
is how it got its name.
In Roman mythology,
“Mercury” was the name
of the swift-footed
messenger of the gods.
Mercury and friends
Th
eE
ar
th
’s
at
m
os
ph
er
e i
s t
hic
k enough to protect it from
m
ostasteroids.
Today, the Mariner 10
space probe is still in
orbit around the Sun.
The days on Mars are
almost the same length
as those on Earth, but the
seasons are twice as long.
Rivers once
flowed on the
surface of Mars.
Mercury, Venus, Earth, and Mars are known as the “inner
planets” because they are the nearest to the Sun. These globes
are made up of the same kind of materials – mainly rocks and
metals – and have a solid outer surface called a crust.
Lonely explorer
The US Mariner 10 probe is the only spacecraft
ever to have visited Mercury. It set off in 1973
to help make a map of the planet’s surface.
Collision course
Mariner 10 discovered that
Mercury is covered in large dents
and hollows called craters. These
were caused by rocky objects in
space, called asteroids, which
crashed into the surface of Mercury.
Venus is the closest planet to Earth. Some call it our “twin sister,”
because it is almost the same size and is made up of the same kinds
of rocks and metals as Earth. But it is not a good home for humans.
This picture of the landscape
on Venus was made by a
computer, using information
from the Magellan
spacecraft.
There are no rivers,
seas, or oceans on the
surface of Venus.
• Planet Venus is named after
the Roman goddess of love.
• The sky is orange on this
planet, and it is always cloudy.
• The atmosphere on Venus
is like a pressure cooker. Visitors
would shrivel up in seconds
and roast like potatoes!
Data zone
20
Sister Venus
Poisonous planet
Venus has a cloudy, swirling atmosphere – like
planet Earth has – but Venus’s is burning
hot and poisonous. The yellow clouds in
the sky are full of a harmful acid. If it
rained, it would burn our skin.
Stormy winds blow
the clouds around the
planet at high speeds.
THE LONGEST DAYS IN SPACE?
On Earth, there are 24 hours in a day
and 365 days in a year. A Venus year is
shorter than ours – 225 of our Earth days.
But the really amazing thing about
Venus is the length of its days, which
last for 243 Earth days. This means that a
Venus day is actually longer than a Venus year!
21