It’s not much different. That doesn’t mean DM is wrong, though! Logically, there’s two possibilities: laws of gravitation are 100% correct at all scales and the

It’s not much different. That doesn’t mean DM is wrong, though! Logically, there’s two possibilities: laws of gravitation are 100% correct at all scales and the discrepancies we see at level of galaxy rotations, etc, are due to matter we can’t yet observe in other ways (hypothesized dark matter). Other option is gravity dynamics are in need of further refinement, much like GR refined Newtonian gravity. Or some combination... maybe GR isn’t the full story but dark matter is also a real thing. Earlier discussion: https://news.ycombinator.com/item?id=19605065 https://news.ycombinator.com/item?id=19605065 I think there’s often sloppiness in how things are stated - dark matter is inferred based on observation of X (edges of galaxy rotate too fast) and an assumption that GR is 100% correct. X is then said to be “evidence for DM”, but there’s that unstated premise.