Why Is Space If It Is Mostly Empty?

Imagine a room in your house after you have cleaned it. It looks empty because there are no toys or clothes lying around. But if you look closely with a super microscope, the air is still there! The space between atoms is also full of invisible things zipping around.

In space, between the stars and planets, there is very little matter like gas or dust. However, it is not truly empty. According to science, the vacuum is actually teeming with virtual particles. These are tiny bursts of energy that pop into existence and disappear almost instantly. They are like bubbles in boiling water, constantly appearing and vanishing.

This hidden energy pushes outward on the universe. It helps galaxies move apart from each other. So when we look up at the night sky, we see stars far away, but even between them, there is a lot of activity happening that holds the universe together.