Seeing the Universe’s Distant Past

The universe is so big that light itself struggles to cross it. Light is the fastest

thing that exists, yet it still takes over 13 billion years to reach us from the edge of

the observable universe. That means when we look into space, we’re not seeing things as they are

right now. We’re seeing the past. Some of the stars you see in the night

sky are already dead — they exploded millions of years ago, but their light

is only reaching Earth now. There are galaxies so far away that their light will

never reach us, no matter how long we wait. The universe is expanding faster

than light itself can travel. So every second, entire galaxies disappear forever