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Related effects have been the topic of numerous papers, and often get hand-waved away without a coherent argument. I've seen statements along the lines of: "Tha
by jiggawatts 4y ago
Related effects have been the topic of numerous papers, and often get hand-waved away without a coherent argument. I've seen statements along the lines of: "That might be true, but then we'd have to rewrite our simulation codes, and that's expensive... so... you see..."
An example of an effect that may actually be relevant to galaxy rotation curves: A strong gravitational well focuses light like a lens, and it ought to focus gravity like a lens also! This means that a star at the edge of a galactic disk ought to see "more" of the gravity from stars on the opposite edge due to the focusing effect of the galactic bulge in between.
A similar effect I've heard talked about is that the the entire galaxy is effectively warping spacetime, which means that the edge moves through time faster than the centre. It's a small effect, but it compounds with the one above to further increase the apparent velocity of the stars at the edge.
- uoaei 4y agoDo you have any papers (for a reading group for interested yet naive physicists) that discuss this lensing-of-gravity phenomenon? As I understand it, what you describe could be an alternative to dark matter that isn't MOND. Since you sound well-versed in the subject -- what do you think of entropic gravity?
- jiggawatts 4y agoI don’t have hyperlinks handy, unfortunately. The other paper I’m thinking of basically stated that the full GR model could also explain most of the rotation curves. That paper was disregarded because it had a discontinuity at the rotation axis, which is non-physical. They turned out to be a side effect of a simplifying assumption and can be corrected, but by then it was too late and the dark matter people moved on…
- simonh 4y agoArguably if the originators of a theory can't be bothered to properly work it out and demonstrate it's viability, why should anyone else?