Why Space Keeps Getting Bigger

Here is a wild secret about our universe: it is growing! Right now, while you read this, every faraway star is drifting a tiny bit farther away. Space is not staying the same size. It is stretching, like a giant balloon puffing up bigger and bigger. Scientists found this out about 100 years ago, and it surprised everybody.

- That the whole universe is getting bigger - A balloon trick that shows how space stretches - That faraway galaxies are moving away from us - The name of a scientist who spotted this

Blow up a balloon just a little. Draw two dots on it with a marker. The dots are like two galaxies, which are huge groups of stars. Now blow more air in. Watch the dots! They slide apart, even though you did not move them. The balloon skin stretched and pushed them away from each other. That is exactly what space does to galaxies.

About 100 years ago, a scientist named Edwin Hubble looked through a giant telescope. He noticed that faraway galaxies were racing away from us. Even stranger, the ones farthest away were zooming away the fastest. That was the big clue that all of space was stretching, not just a few stars moving. A famous space telescope is named Hubble after him.