- #1
Aschere
- 19
- 0
I was wondering, if dark matter (DM) halos are spherical in nature and increase in density as a function of distance from the galactic core,
why does the density drop off so suddenly
and
why would stars on the edge of a galaxy feel an inward pull?
To elaborate on the 2nd question, if DM interacts only gravitationally and is more dense at the edge of the galaxy (or a radius from it), wouldn't stars want to be gravitationally tugged by the DM away from the galaxy and not towards the galactic core? Rotation curves suggest stars on the edges of spirals are being pulled 'inward', but the DM is in the opposite direction for that!
why does the density drop off so suddenly
and
why would stars on the edge of a galaxy feel an inward pull?
To elaborate on the 2nd question, if DM interacts only gravitationally and is more dense at the edge of the galaxy (or a radius from it), wouldn't stars want to be gravitationally tugged by the DM away from the galaxy and not towards the galactic core? Rotation curves suggest stars on the edges of spirals are being pulled 'inward', but the DM is in the opposite direction for that!