The Big Bang
Astronomers think that the Universe started with a giant explosion called the Big Bang. Why do we think this?
We know from looking at the redshift of distant galaxies that the Universe is expanding.
Of course, if you imagine going backwards in time, that means that the galaxies will be getting closer together.
If you go back far enough, all of the galaxies, and indeed everything in the Universe will be in one place!
If you then imagine switching to going forwards in time again, everything in the Universe will suddenly "fly apart" in something a bit like an enormous explosion. This is what astronomers call the Big Bang.
Some Frequently Asked Questions
- What happened during and after the Big Bang?
- Where was the Big Bang?
- What will happen to the Universe in the future?
- Why do astronomers think the Big Bang happened?
