| > Why? Because all of the other theoretical models that attempt to explain the observed redshifts fail to match observations. > Maybe... just maybe... that's because it isn't actually expanding, but there's some other, unknown effects at play? Nope. Already been tried. Doesn't work. > It's about time we think outside the box. Cosmologists have been trying out of the box ideas for decades. All of them failed. That's why we have the models we have now: they're the only ones that survived that process. > I get it, both make the calculations work out, but they're basically "we have no clue what this actually is, here's our best guess" kind of variable. For dark matter, you are correct: we don't know what it is, and the term is basically just another way of saying "whatever we need to add to our model to make it match observations works basically like ordinary matter does in the equations". But that is not true of expansion itself. All of the alternative models that have been proposed to eliminate the need for dark matter still have an expanding universe. The expansion itself is a much more solid conclusion than dark matter is. |