Is it Dark Energy? Or is Time Just Running at Varying Speeds? The Timescape Model
New evidence challenges the existence of dark energy. But does the timescape model really solve the question surrounding the accelerated expansion of the universe? This graph shows the timeline of the universe, including the accelerated expansion of the universe; Source: Nasa Lambda We still don’t know what dark energy is. In fact, one theory in particular has gained recent traction that it doesn’t exist at all. And it all relies on one assumption: that the universe is not homogeneous. On large enough scales, the universe is homogeneous and isotropic—in other words, that the universe essentially looks the same if you look far enough out. This is what the Lambda-CDM model tells us, also known as the standard model of Big Bang cosmology. It’s a good theory. Not only because it’s based on general relativity, it also explains why the cosmic microwave background (the first light of the universe) exists, how dark matter holds galaxy clusters together, and that dark energy accelerates...