TurtleStudios t1_iu9h9h0 wrote on October 29, 2022 at 4:29 PM

Reply to comment by Aseyhe in Is dark matter orbiting galaxies with the same speed as normal matter? by taracus

Haven't microlensing studies ruled out the idea of a halo of primordial black holes around the galaxy?

Aseyhe t1_iu9k5lj wrote on October 29, 2022 at 4:50 PM

Yes for earth-mass black holes, but no for the asteroid-mass range. Also, microlensing constraints are sensitive to the degree to which the black holes are clustered, which is a topic of ongoing study.

enmacdee t1_iucmm9v wrote on October 30, 2022 at 9:05 AM

Unrelated question. But how can you have a black hole of mass earth or asteroid. Isn’t the whole idea of a black hole that the gravity is so strong it bends light. If something only has the same mass as the earth how is it able to bend light? Thanks!

Aseyhe t1_iucns8k wrote on October 30, 2022 at 9:21 AM

You can make almost anything a black hole if you compress it small enough. If you compressed the earth down to about a centimeter, it would become a black hole. For a 10^20 gram asteroid, the relevant size is under a nanometer.