So the Universe expanded very rapidly in its very first moments (inflation). The Universe then slowed down and is speeding up again, and Dark energy is supposed to be responsible for this accelerated expansion. The cosmological constant might as well be dark energy, but why is it still being considered when the Universe's expansion's rate has changed over time? And the cosmological constant is constant, so it should remain constant since it existed, right? So I'm guessing my question is, why do physicists still consider the cosmological constant if the Universe's expansion rate has changed over time? Or was dark energy simply not responsible for inflation?