New answers tagged

29

Dark matter galaxies are possible but very speculative. On a theoretical level, they are hard to form because dark matter interacts only gravitationally (see Anders Sandberg's answer), which makes it hard to lose energy and become bound structures. On an observational level, they would be hard to detect. Gravitational lensing can do something, but since one ...


4

Gravitational lensing observations suggest that there is a large mass of dark matter on either side of the bullet cluster, which is actually one of the major pieces of evidence that dark matter does indeed exist. This dark matter essentially "left behind" the majority of the normal matter in the galaxies it was with as two galaxy clusters collided ...


27

Probably not. Dark matter should really be called "transparent matter" since it does not interact with light. This has an important consequence: it is hard for dark matter - whatever it is - to lose energy by radiating. This is why normal matter can form clouds that accrete into dense regions that in turn become galaxies and stars: energy is ...


Top 50 recent answers are included