When we look up at the night sky, we can only see a small percentage of the stars that are around us.
That's because our eyes can only see so far.
Telescopes on earth have helped us get a better view of the stars by collecting more light than our eyes can see
allowing us to see even further.
But the view from those telescopes gets distorted by Earth's atmosphere.
That's why we see the stars twinkle.
To get rid of the distortion of the atmosphere,
astronomers imagine building a telescope
the size of a school bus to go into space.
The result was the Hubble Space Telescope launched in 1990.
Today it orbits the Earth, 340 miles above the surface.
Many of the galaxies Hubble photographs are millions of light-years away from Earth.
Light-years are a measurement for distance in space,
related to the time it takes light to travel from one place to another.
A light-year is the distance light travels in one year.
Hubble photographed the Whirlpool Galaxy that is 25 million light-years away from Earth.
The light from that Galaxy took 25 million years to travel to Earth.
This means that the light Hubble sees from the Whirlpool Galaxy,
is 25 million years old.
We aren't seeing the Galaxy as it exists today.
We're seeing the Galaxy as it existed
25 million years ago.
A Hubble astronomer had a really interesting idea
to point Hubble at an apparently blank spot of sky
to see what we could see.
That empty patch of sky
turned out to be filled with galaxies,
much more distant than we'd ever seen before.
Some of the galaxies were baby galaxies,
born just after the creation of the universe and the Big Bang.
The universe is a never-ending source of wonder
largely because of the things the Hubble Space Telescope has taught us during its years in space.
Hubble studies our own solar system,
like storms on Mars,
the rings of Saturn,
and aurora on Jupiter.
Hubble also photographs the birth and death of stars,
and has uncovered thousands of new galaxies in the universe.