I am trying to wrap my brain around the idea of the cosmological constant, and how it gives the result of an accelerating universe. I have read different explanations for it, and in some it gives me the impression that it is an actual physical force, pushing everything away from everything else. While in others I get the impression I should look at it as thought space itself is expanding, meaning that even though 2 objects aren't actually being pushed away from each other, the space between them is expanding. So which one is it? Or am I totally misunderstanding the whole thing?