4 ms·
How can it have mass / interact gravitationally and not make "clumps"?
by nerfhammer 10y ago
How can it have mass / interact gravitationally and not make "clumps"?
- okket 10y agoSee http://physics.stackexchange.com/questions/214950/if-dark-matter-only-interacts-with-gravity-why-doesnt-it-all-clump-together-in http://physics.stackexchange.com/questions/214950/if-dark-ma... TL;DR: Dark Matter doesn't clump because of missing "friction" from the other forces, esp. electromagnetic/weak.
- Florin_Andrei 10y agoGravity only pulls things together, it doesn't stop them when they get close to each other. In the absence of "friction" (all other interactions except gravity), things get close to each other and just zoom past by / through each other. If you only have gravity but nothing else, there are no collisions. If you've seen the CUDA demo where they simulate thousands of bodies interacting by gravity, and they just keep swarming around forever - it's like that. No friction or stickiness, no collisions, just forever swarming around. Dark matter, whatever it really is, is rather like a "ghost". Just goes through normal matter and through itself and doesn't do anything except a little gravitational tug.