Originally published at: https://bigideas.network/dark-energy/
In 1929, astronomers discovered something that shattered their previous conceptions about the universe.
The universe was expanding.
In the years that followed they reasoned that if it was expanding, then in the past it must have been smaller. If you went back far enough, you should find a single point of origin followed by an explosion.
This is the idea behind the Big Bang.
But they were in for another surprise. They later found that this expansion was accelerating…