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If it interacted with itself in ways other than just gravity, it would make clumps. The problem is, it doesn't make clumps. Its distribution is very clearly non
by Florin_Andrei 10y ago
If it interacted with itself in ways other than just gravity, it would make clumps. The problem is, it doesn't make clumps. Its distribution is very clearly non-clumpy.
Also, if this was gravity leaking between parallel universes, I believe it would produce measurable artifacts, and therefore could be tested.
- raattgift 10y agoIt's useful to add to this that "interacting with itself" in a way that allows clumping implies radiative dissipation of momentum or elastic collision or both. Without that it takes much longer to ditch enough momentum to fall into an orbit closer to the centre of mass around which it's moving. That is, the non-clumpiness implies that if there is dark chemistry, the reactions must take a long time compared to the present age of the universe.
- flukus 10y agoCan we say it doesn't clump or can we only say it doesn't clump on the galactic scale? Could it clump but then go into it's equivalent of a super nova with very small clumps?
- raattgift 10y agoThis is a pretty good question. There is a limit to the changes in the momentum of cold dark matter before it produces visible effects in galaxies of different ages. Explosive processes in the dark matter sector must be rare, whatever their mechanism and whatever their daughter products (even if it quickly decays to cold dark matter again, but on a different trajectory).