Everything started with the Big Bang. Most astrophysicists agree that the force generated by the Big Bang continues to push stars, planets, and galaxies apart from each other as our universe expands.
Where they haven’t always agreed — and in some ways, still don’t, is how quickly that is happening, and what happens far down the road. One popular theory around for decades is known as the Big Crunch — basically the opposite of the Big Bang, when everything will stop expanding and get sucked back together again.
“Galaxies are not just receding away from each other, but it speeds up over time,” says Avi Loeb, an astrophysicist at Harvard University.
This idea fell out of favors in the late 1990s with the discovery of dark matter and what scientists at the time believed was proof of the accelerating expansion of the universe. The Big Crunch theory died for a ...
