>>13671987Here's an example of NASA explaining dark energy. The universe is certainly expanding, which means that if you go back in time, obviously it was smaller. That in essence is one of the reasons the big bang seems credible as the true theory. But predictions about the rate of expansion that use modern models of gravity are actually demonstrably wrong.
One largely believed theory right now is that there is actually invisible matter/energy that is therefore "dark" because we simply can't detect it yet, and that energy is facilitating this increased rate of expansion.
And also the rate at which galaxies move appears to also contradict modern science's predictions. Which is where the theory for "dark matter" came from. So dark energy is the theory for why the universe is expanding faster than science says it should, and dark matter is the theory trying to explain why galaxies don't actually move the way science says they should!
