Science Common Sense

1543 - Why is our universe composed of various celestial bodies of different scales and expanding?

Imagine you blew up a big balloon and it's still growing. That's like what's happening with our universe.

A long, long time ago, about 13.8 billion years ago, there was a huge explosion called the Big Bang. It created a small, hot universe that grew and expanded really fast.

As it expanded, the universe started to cool down and form particles, like tiny atoms and eventually bigger things like stars, galaxies, and planets. These particles came together under their own gravity to form bigger and bigger things.

This is why our universe has different sizes of celestial bodies like stars, planets, galaxies, and even galaxy clusters. Everything is still moving away from each other because the universe is still expanding.

It's like the balloon is still growing, and all the dots on the balloon (the galaxies) are moving away from each other. But instead of being on a balloon, these galaxies are in space, and they're all part of our vast and amazing universe!