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When we look up at the night sky, we can only see a small percentage of the stars that are around us.

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That's because our eyes can only see so far.

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Telescopes on earth have helped us get a better view of the stars by collecting more light than our eyes can see

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allowing us to see even further.

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But the view from those telescopes gets distorted by Earth's atmosphere.

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That's why we see the stars twinkle.

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To get rid of the distortion of the atmosphere,

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astronomers imagine building a telescope

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the size of a school bus to go into space.

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The result was the Hubble Space Telescope launched in 1990.

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Today it orbits the Earth, 340 miles above the surface.

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Many of the galaxies Hubble photographs are millions of light-years away from Earth.

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Light-years are a measurement for distance in space,

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related to the time it takes light to travel from one place to another.

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A light-year is the distance light travels in one year.

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Hubble photographed the Whirlpool Galaxy that is 25 million light-years away from Earth.

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The light from that Galaxy took 25 million years to travel to Earth.

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This means that the light Hubble sees from the Whirlpool Galaxy,

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is 25 million years old.

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We aren't seeing the Galaxy as it exists today.

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We're seeing the Galaxy as it existed

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25 million years ago.

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A Hubble astronomer had a really interesting idea

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to point Hubble at an apparently blank spot of sky

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to see what we could see.

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That empty patch of sky

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turned out to be filled with galaxies,

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much more distant than we'd ever seen before.

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Some of the galaxies were baby galaxies,

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born just after the creation of the universe and the Big Bang.

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The universe is a never-ending source of wonder

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largely because of the things the Hubble Space Telescope has taught us during its years in space.

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Hubble studies our own solar system,

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like storms on Mars,

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the rings of Saturn,

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and aurora on Jupiter.

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Hubble also photographs the birth and death of stars,

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and has uncovered thousands of new galaxies in the universe.