Olbers' paradox

Olbers' Paradox is like a math puzzle. It asks why is it dark at night when the sky should be filled with stars. To solve it, you can imagine an empty box with some dots in it. If the box was really big and the dots were really tiny, it'd be really hard to find the empty spaces in between. In the same way, no matter where you look in the sky, you'd see stars, and it would be bright all the time. But, it's not like that in our universe, so something else is happening. Scientists think that since the universe is really big, the stars we can see are only a tiny fraction of the stars in the universe, and the ones we can't see are really far away. That's why it's dark at night - because the stars we can't see are too far away for us to see.