You have likely heard about the Universe expanding. Or that redshift can tell us about the movements of galaxies. Both are difficult ideas to imagine and understand.
Where did the Big Bang take place? If the Universe is expanding, where is it expanding from? These are very good questions, but the answer might seem confusing. The answer is...everywhere!
The Universe began with the Big Bang about 14,000 million years ago (14,000,000,000 years). When it was young, the Universe was very, very hot and dense. Since then, it has been cooling down and getting bigger.
Astronomers think the Big Bang is the best way to explain how the Universe started and how it changed over time. All science is based on evidence. So what is the evidence for the Big Bang?
The Big Bang is the explanation for how the Universe started. Astronomers think that everything started in a single point. Then everything expanded and stretched to grow into the huge Universe we see today.