“We’ve known for a long time that the universe is expanding. But about 15 years ago, my colleagues and I discovered that it is expanding faster and faster. That is, the universe is accelerating, and that was not expected, but it is now attributed to this mysterious stuff called dark energy which seems to make up about 70 percent of the universe.” -Adam Riess
The Universe has been said to be not only stranger than we imagine, but stranger than we can imagine. After the discovery of the expanding Universe, scientists considered that there was a great cosmic race from the moment of the Big Bang between the initial expansion and the force of gravity, which works to pull everything back together.
It was quite a surprise when dark energy was discovered, giving us a Universe that doesn’t slow down in its expansion over time, but rather accelerates. Yet we often overlook exactly how dark energy was such a surprise. A look back at the top differences between Universes with and without dark energy, including for the fate of the local group, our local supercluster, and the far reaches of our Universe and what we can eventually see, really highlights the magnitude of just how significantly dark energy changes everything.