Dark Matter and Cosmology

Question 1

What pieces of observational evidence are there for the existence of dark matter?

Answer 1

Rotational curves - constant rotational velocity instead of decreasing with r
Gravitational lensing - larger mass than expected
Colliding galaxy clusters

Question 2

What are some things that are NOT dark matter?

Answer 2

baryonic matter (must be small fraction of total dark matter)
antimatter (would be detected by gamma rays)
relativistic particles (can not clump together)
charged particles (dark matter very rarely interacts)

Question 3

What are some suggested candidates for dark matter?

Answer 3

WIMPs - weakly interacting massive particles
axions and axion-like particles
primordial black holes