Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: thedoc on 22/07/2015 07:50:01

Title: Could black holes be made of dark matter?
Post by: thedoc on 22/07/2015 07:50:01
John Dye asked the Naked Scientists:
   
Can dark matter be the contents of black holes which would then explain the increase in the expansion of the universe speed due to the increase in dark energy? More dark holes result in more dark matter/energy?

What do you think?
Title: Re: Could black holes be made of dark matter?
Post by: evan_au on 22/07/2015 12:56:15
Quote from: John Dye
Can dark matter be the contents of black holes?
The composition of Dark Matter (https://en.wikipedia.org/wiki/Dark_matter#History_of_the_search_for_its_composition) is still a matter of some debate for physicists. This year, most are guessing that it is some type of Weakly Interacting Massive Particle (or WIMP, for short), and there are searches underway to try and find it (with no announcements to date).

An older theory was that Dark Matter could consist of MAssive Compact Halo Objects or MACHOs, which includes candidates like black holes. Undoubtedly, there are many "silent" black holes floating around our galaxy, which are invisible because they are not actively consuming matter at present. However, searches for gravitational microlensing events showed that there are not nearly enough MACHOs to account for the effects of Dark Matter.

The main connection between Dark Matter (which is attractive, adding to gravitational attraction) and Dark Energy (which is repulsive, overcoming gravitational attraction) is that they are both called "Dark", ie "we can't see it, and we don't know what it is".
Title: Re: Could black holes be made of dark matter?
Post by: PmbPhy on 22/07/2015 13:35:53
Quote from: thedoc
Can dark matter be the contents of black holes which would then explain the increase in the expansion of the universe speed due to the increase in dark energy? More dark holes result in more dark matter/energy?
When matter is absorbed by a black hole it looses all its identity that it had before it was captured. However a black hole itself is one possible candidate for dark matter.