Do waves hold the secrets of space? - ��˿�� Bitesize

Imagine that you’re just about to take your first spacewalk. As you go through the hatch, the International Space Station (ISS) is moving at around 17,000 miles per hour. The earth’s surface is 250 miles below you.

You’re sweating, and your heart is hammering loudly. The voices of your crew crackle on the radio. But outside of your spacesuit, everything’s quiet. There’s no noise at all.

So what’s the story here traveller? Light travels across space, but what about sound?

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Tim Peake and Fran Scott explain why you can't hear anything in space. Archive: ESA, NASA

The fiery surface of the sun — Image caption,
It might look nearby, but the Sun is actually over 90 million miles away. It still takes light about eight minutes to travel from the Sun to Earth. NASA/SDO

The story of starlight

Although sound waves can’t travel in space, light waves can. That’s why everything we know about the Universe comes from light.

Light travels at an amazing 299,792 kilometers per second. It can go seven-and-a-half times around the world in one second. But even at this speed, it takes light over 100,000 years to travel across our galaxy alone. The entire Universe is so big that many stars are already dead by the time their light reaches us.

Scientists have discovered that each star has its own unique light reading. Even though we could never visit them, we can use their light to study them. Written in the starlight is information about a star’s age, surface temperature and the direction it’s heading.

Astronomers have used light to reveal even more about space. They have discovered alien worlds, the age of our Universe and even the forces at play around a black hole. In short, light is helping us unlock some of space’s greatest mysteries.

Explore the gallery below to find out about some of the most beautiful and extraordinary images of our Universe.

Space gallery

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This image shows the earth rising above the surface of the Moon. It was taken by astronauts on-board the Apollo 17 spacecraft (the last manned mission to the Moon) as they orbited the lunar surface in 1972. NASA
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These pictures taken by the Suomi NPP satellite shows what Earth looks like from outer space. The satellite took hundreds of different photographs to give a complete map of our planet. NASA/NOAA/Suomi NPP
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Robotic rovers and landers have been sent to explore some of the planets and moons in our solar system. In 2014, NASA’s Curiosity rover sent back this ‘selfie’ from the surface of Mars. NASA/JPL-Caltech/MSSS
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This image of Saturn’s rings was taken by NASA’s Cassini probe in 2013. That tiny pale blue dot in the distance is the earth viewed from 900 million miles away. Before the picture was taken, NASA asked people to look up and smile for the camera. NASA/JPL-Caltech/Space Science
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For years the surface of Pluto was a mystery, but in July 2015 the New Horizons probe beamed back images in brilliant detail. It showed a beautiful, icy world with a great heart-shaped plain, mountains and possibly glaciers of frozen nitrogen. NASA/JHUAPL/SwRI
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For over 25 years the Hubble Space Telescope has given us a glimpse into the furthest reaches of our Universe. This image of the Orion Nebula is just one of them. Nebulas are vast clouds of dust and gas where stars form. NASA/ESA/M. Robberto
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The Hubble Telescope also allows us to look at galaxies beyond our own, which is known as the Milky Way. A galaxy is a giant swirling mass of hundreds of billions of stars, all spiraling around a supermassive black hole at their centre. ESA
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In 2004 Hubble examined a seemingly empty patch of sky. The points of light in this picture are not stars, they're galaxies - each of hundreds of billions of stars. You could cover everything in this image with a sand grain held at arm’s length. NASA/ESA/STScI

The Hubble Space Telescope floating above the Earth — Image caption,
The Hubble Space Telescope has made countless discoveries and taken countless beautiful images of space. It's over 340 miles above Earth - far above the weather and light pollution that might distort its view. NASA

Your eyes in the sky

Your eyes aren't powerful enough to see all the secrets of space. That’s why scientists use telescopes, satellites and probes to observe the Universe in greater detail. These instruments can also pick up light that is undetectable to our eyes.

Studying light on Earth has a few problems. The earth’s atmosphere disturbs and blurs our pictures of the Universe. But by putting telescopes into space, you can solve these problems instantly.

Satellites and probes offer similar benefits. Probes are unmanned spacecraft on a one-way ticket into space. They pick up scientific data about our Universe and beam it back to Earth.

Some probes orbit and land on different planets. Others head out into space. The probe Voyager 1 set off on its journey in 1977 and it’s now over 12 billion miles away.

No doubt you’ll see some major space technology breakthroughs during your lifetime. Who knows what we’ll uncover?

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The story of starlight

Space gallery

Your eyes in the sky

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