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WHATEVER you do, don’t ask where it happened. “The most common misconception is that the big bang was an explosion in a particular place,” says William Kinney, a cosmologist at the University at Buffalo in New York. “That’s just completely wrong.”
The best evidence for the big bang is all around us in the cosmic microwave background, the radiation released once the universe had cooled sufficiently for atoms to form, when it was about 380,000 years old. And that is the point: everywhere in today’s universe was where the big bang was. “It’s not something that happened somewhere, but something that happened everywhere, including the space you happen to be occupying now,” says Dan Hooper at Fermilab in Illinois.
When cosmologists talk about the big bang, they are talking about an extremely dense, hot state that existed around 13.8 billion years ago and which has since expanded and cooled to make the universe we know today. Extremely dense and hot – but not infinitely so.
The idea that the universe was created from an infinitesimal speck, known as the big bang “singularity”, comes from winding the showreel of an expanding, cooling universe backwards and not stopping until we get to a beginning. But, unfortunately, our current theories of physics can’t deal with space and time on such unfathomably small scales. So we can say nothing sensible about the moment when the universe was a single point, if indeed it ever happened. “We may just have to come to terms with that,” says Kinney.
“The big bang didn’t happen somewhere, it happened everywhere”
However it all started, the big bang that …
