Is there any evidence for dark matter?

Question

I have always heard about dark matter, but I do not know what it means, what its uses are, and does it really exist?

In: Chemistry

Answer 1

To my understanding it’s not so much a substance as a theoretical explanation for why stars don’t always seem to behave the way they should, given our understanding of physics.

When reality doesn’t conform to your theory, the possible explanations are that your theory is wrong, or that there’s some unknown variable that accounts for the discrepancy. In this case, if the theory is wrong, then why does it seem to predict so many other things accurately? So the (proposed) unknown variable is lots of extra matter that for some reason we can’t see, thus labeling it “dark.”