What is 13.8 billion years?

13.8 billion years is how long ago the universe started, and it’s like having a really long birthday party that began way before anyone you know was even born.

Imagine you're holding a big, empty balloon in your hands, just air inside, nothing else. That’s what the universe looked like when it first started. Then, poof! It began to grow and expand, like blowing up a balloon. This growing has been going on for 13.8 billion years, which is longer than the time since humans walked on Earth.

Let’s say you have a jar with 100 jellybeans in it, and each jellybean stands for one year of your life. If you had 13.8 billion jellybeans, that would be like having enough jellybeans to last way longer than anyone has ever lived, even your grandpa or great-grandpa! That's how long the universe has been growing.

So, 13.8 billion years is a super long time, it’s like the universe had its big birthday party, and it’s still going on!