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The idea here (timescapes) is specifically about dark energy, not dark matter. EDIT: But, yes, if there's lots of dark matter not uniformly distributed in the

The idea here (timescapes) is specifically about dark energy, not dark matter. EDIT: But, yes, if there's lots of dark matter not uniformly distributed in the universe, then that dark matter would have differing effects on time dilation in different parts of the universe. Questions: Do the great voids contain much dark matter? What about non-void areas that also have very little DM somehow?

schiffern 2y ago
To me it sounds like they understood that, but they're asking how dark matter (and its gravity) might interact with this model.
- cryptonector 2y ago
  I see no way in which timescapes deals with DM, and the authors don't seem to think so either.
  - deleted 2y ago
    [deleted]
dazzaji 2y ago
Thanks for clarifying that timescape cosmology focuses on dark energy, not dark matter—makes sense they’re addressing different puzzles. That said, I’m curious: could there be any indirect connection between the two? For instance, if dark matter’s influence on gravity shapes the 'lumpiness' of the universe, could that, in turn, amplify the time dilation effects discussed in timescapes? I realize the authors didn’t delve into dark matter, but wondering if anyone has explored how these two phenomena might interact. Definitely out of my depth here, but this potential connection is what sprung to mind and on rare occasions my ill-informed intuitive curiosities turn out to have unexpected merit, so I’m asking if there could be anything to it?
- cryptonector 2y ago
  > could there be any indirect connection between the two? Unlikely. DE and DM are very different problems, sharing only a word in their casual names: dark :) The galaxy rotation problem requires either modified gravity (MOND, etc.), actual dark matter, finding that the measurements and/or their interpretation are wrong, or something else. There are some GR effects to consider, mainly frame dragging, but frame dragging doesn't seem to be anywhere near enough because the frame dragging effect diminishes with the same proportion as gravity: inverse square distance.

schiffern 2y ago

To me it sounds like they understood that, but they're asking how dark matter (and its gravity) might interact with this model.

cryptonector 2y ago
I see no way in which timescapes deals with DM, and the authors don't seem to think so either.
- deleted 2y ago
  [deleted]

dazzaji 2y ago

Thanks for clarifying that timescape cosmology focuses on dark energy, not dark matter—makes sense they’re addressing different puzzles. That said, I’m curious: could there be any indirect connection between the two? For instance, if dark matter’s influence on gravity shapes the 'lumpiness' of the universe, could that, in turn, amplify the time dilation effects discussed in timescapes? I realize the authors didn’t delve into dark matter, but wondering if anyone has explored how these two phenomena might interact. Definitely out of my depth here, but this potential connection is what sprung to mind and on rare occasions my ill-informed intuitive curiosities turn out to have unexpected merit, so I’m asking if there could be anything to it?

cryptonector 2y ago
> could there be any indirect connection between the two? Unlikely. DE and DM are very different problems, sharing only a word in their casual names: dark :) The galaxy rotation problem requires either modified gravity (MOND, etc.), actual dark matter, finding that the measurements and/or their interpretation are wrong, or something else. There are some GR effects to consider, mainly frame dragging, but frame dragging doesn't seem to be anywhere near enough because the frame dragging effect diminishes with the same proportion as gravity: inverse square distance.