Curious Kids is a series for kids of all ages. If you have any questions you would like an expert to answer, please send them to [email protected].
How could a Big Bang be the beginning of the universe, as intense explosions destroy everything? – Tristan S., 8, Newark, Delaware
Pretend you are a perfectly flat chess piece in a chess set on a perfectly flat and huge chessboard. One day you look around and ask: How did I get here? How did the chessboard come about? How did it all start? Take out your telescope and start exploring your universe, the chessboard …
What do you find? Your universe, the chessboard, is getting bigger and bigger. And with more time, even bigger! The dashboard is expanding in all directions you can see. From what can be said, there is nothing to cause this expansion, but it seems to be the nature of the chessboard.
But wait a minute. If it is getting bigger and bigger and growing, it means that in the past it should be getting smaller. At some point, very, very long, at first, it must have been so small that it was infinitely small.
Let’s move forward from what happened then. At the beginning of your universe, the chessboard was infinitely small and expanded, growing more and more until the day you decided to make some observations about the nature of your chess universe. All the things in the universe, the little particles that make up you and everything else, started very close together and separated as time went on.
Our universe works in exactly the same way. When astronomers like me make observations of distant galaxies, we see that they are all separating. It seems that our universe started very small and has been expanding ever since. In fact, scientists now know that the universe is not only expanding, but increasing the speed at which it is expanding. This mysterious effect is caused by something that physicists call dark energy, although we know very little about it.
Astronomers also observe something called cosmic microwave background radiation. It is a very low energy level that exists throughout the space. We know from these measurements that our universe is 13.8 billion years old, that is, much larger than humans and about three times longer than Earth.
If astronomers look back to the event that started our universe, we will call it the Big Bang.
A lot of people hear the name “Big Bang” and think of a giant explosion of things, like a bomb is on. But the Big Bang was not an explosion that destroyed things. It was the beginning of our universe, the beginning of space and time. More than an explosion, it was a very rapid expansion, the event that made the universe bigger and bigger.
This expansion is different from an explosion, which can be caused by things such as chemical reactions or large impacts. Explosions result in energy going from one place to another and usually a lot. In contrast, during the Big Bang, energy moved along with space as it expanded, moving wildly, but spreading over time as space grew with the passage of time.
Back in the chessboard universe, the “Big Bang” would be like the beginning of it all. It is the beginning of the rise of the board.
It’s important to realize that “before” the Big Bang there was no space or time. Going back to the chessboard analogy, you can count the amount of game clock time after start, but there is no game time before you start, the clock did not work. And, before the game started, the universe of boards did not exist and there was no space on the boards either. In this context, you have to be careful when you say “before” because there was not even time until the Big Bang.
You’ve also surrounded your idea that the universe doesn’t expand “into anything,” because as far as we know, the Big Bang was the beginning of space and time. Confused, I know!
Astronomers are not sure what caused the Big Bang. We just look at observations and see that this is how the universe began. We know it was very small and it got bigger, and we know it started 13.8 billion years ago.
What started our own game of chess? This is one of the deepest questions anyone can ask.
Hello, curious children! Do you have any questions you would like an expert to answer? Ask an adult to send your question to [email protected]. Tell us your name, age and the city where you live.
And since curiosity has no age limit: adults, let us know what you’re wondering too. We will not be able to answer all the questions, but we will do our best.
This article is republished in The Conversation, a non-profit news site dedicated to sharing ideas from academic experts.
Read more:
Michael Lam does not work, consult, share, or receive funding from any company or organization that may benefit from this article, and has not disclosed any relevant affiliation beyond his academic appointment.