DK - WOW! The Visual Encyclopedia of Everything

289

There is

no sound

in space, as sound cannot travel through a

vacuum

.

Astronauts on the International Space Station

have been growing plants in space. The

techniques they develop will be needed on

any future mission to Mars, as the astronauts

will need to grow their own food.

The Voyager 1 spacecraft

left Earth in 1977

and is now the most

distant human-

made object

in space.

Light from the Sun

takes just over eight

minutes to reach

Earth. The light from

the next nearest star,

Proxima Centauri, takes

4.3 years to reach Earth.

The biggest stars of all are

500 times larger than the Sun

and 100,000 times as bright.

Our Sun is orbiting the black hole at the

centre of the Milky Way galaxy at a speed

of 900,000 km/h (550,000 mph). It takes

225 million years to complete one orbit.

The Universe is expanding in

all directions at the speed of light.

As we look into space we see the Universe as it was

in the past because of the time it takes for the light

of distant stars and galaxies to reach us.

The tail of the Great Comet, which passed by

Earth in 1843 , was more than 800 million km

(500 million miles) long – about the distance

from the Sun to Jupiter.

Mars has ice caps at its

poles, just like Earth.

The largest canyon system in the Solar

System is Valles Marineris on Mars, which

is more than 4,000 km (2,500 miles) long.

Volcanoes

last erupted on

the Moon about

3.2 billion years ago.

The Orion vehicle is NASA’s new

spacecraft. From the early 2020s,

it will carry astronauts to the

Moon and, later, on the first

stage of a mission to Mars.

Yuri Gagarin’s

mother first

found out

about his

flight into

space when

news of

the mission

broke.

It takes the Space Shuttle

eight minutes to reach

its orbital speed of

27,000 km/h (17,000 mph).

Comet Encke is the

most frequent visitor

to Earth, passing by

once every 3.3 years.

There are more than 1 million

asteroids larger than 1 km (0.6 miles)

wide in the Main Belt of asteroids between

the orbits of Mars and Jupiter.

About every 50 million years a meteorite more

than 10 km (6 miles) in diameter hits Earth.

In 1971, US astronaut Alan Shepard stood

on the Moon and hit a golf ball.

Saturn’s rings were first seen by Galileo

in 1610 using one of the first ever telescopes.

Two of the world’s largest optical telescopes

are found at the Mauna Kea Observatory in

Hawaii. The twin Keck telescopes both have

mirrors 10 m (32.8 ft) in diameter.

The largest meteorite on Earth is the Hoba West,

which remains where it fell in Namibia, southwest

Africa. It weighed 66 tonnes when it was found in 1920.

The brightest objects in the

Universe are quasars – extremely

distant galaxies that have incredibly

bright centres. The quasars that

we can see are so far away that

their light has taken billions of

years to reach Earth.

If you counted the stars

in the Milky Way at

a rate of one a

second, it would

take you about

5,000 years to

count them all.

Robert

Goddard first

suggested flying

to the Moon in

a rocket in 1912.

People thought

he was crazy.

FOR MORE FACTS AND FIGURES ABOUT THE UNIVERSE, SEE PAGES 126–151

The planets of

our Solar System

occupy a disc-shaped

region extending

4.5 billion km

(2.8 billion miles)

from the Sun.

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