Could Stellar Black Holes Account for Half of Dark Matter in the Universe?

In summary: If so, then their existence would be limited to galactic centers.All of them? That'd be a neat trick. The galaxy is permeated with dust and gas. Where in the galaxy are all thse expanses of uncharacteristically hard vacuum that these black holes gather?Where do you think they gather? From what I've read, it seems like they would need to be very close to a lot of dense matter in order to form.Where do you think they gather? From what I've read, it seems like they would need to be very close to a lot of dense matter in order to form.
  • #1
Imax
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0
Twenty first century dark matter reminds me of ninetieth century luminiferous aether. Without dark matter, current models of galaxies fall apart. What could happen if some of that dark matter mass was from stellar black holes?

The supermasssive black hole at the center of our galaxy, the Milky Way, is about 10% the mass of our galaxy. In current models, the universe is made up of about 5% matter, the stuff we can see, about 25% dark matter, the stuff we can’t see, and about 75% dark energy.

What would happen to current models if half the dark matter mass (i.e. 10% of the universe) was from stellar black holes? To me, that could mean that there could be a lot more stellar black holes than anticipated from the current model. It could mean that stellar back hole mass is about twice the mass of the universe as we can observe.

Within this model, the universe could be made up of about 5% matter, about 10% stellar black holes, about 15% dark matter, and about 75% dark energy.
 
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  • #2
1] Mass concentrated at a point at the centre of a galaxy would not explain the anomalies. The anomalies suggest an excess of mass in a halo including the outer reaches of the galaxy. http://en.wikipedia.org/wiki/Galaxy_rotation_problem
2] Contrary to popular belief, black holes are very visible and have a distinctive radio signature.
 
  • #3
Stellar black holes would not be concentrated to a center, but could be distributed throughout a galaxy.
 
  • #4
Imax said:
Stellar black holes would not be concentrated to a center, but could be distributed throughout a galaxy.

OK. And point 2?
 
  • #6
The supermasssive black hole at the center of our galaxy, the Milky Way, is about 10% the mass of our galaxy.

Where do you get this? Going by the wikipedia values, Sgr A* is about 4*10^6 solar masses, while the Milky Way is something like 7*10^11 solar masses.
 
  • #7
Imax said:
Twenty first century dark matter reminds me of ninetieth century luminiferous aether.

There is a big difference between the aether and DM. The aether, when we went looking for it, was conspicuously absent, in that predictions using the model failed when it came to actual observation. Predictions based on the DM model however keep bearing fruit.
 
  • #8
DaveC426913 said:
2) Contrary to popular belief, black holes are very visible and have a distinctive radio signature.

Possibly, but only for those black holes near matter. Other black holes could be invisible, with no distinct radio signature.
 
  • #9
Imax said:
Possibly, but only for those black holes near matter. Other black holes could be invisible, with no distinct radio signature.

All of them? That'd be a neat trick. The galaxy is permeated with dust and gas. Where in the galaxy are all thse expanses of uncharacteristically hard vacuum that these black holes gather?
 
  • #10
Imax said:
Possibly, but only for those black holes near matter. Other black holes could be invisible, with no distinct radio signature.

Also, does not the process of black hole formation necessitate that they exist in a nebulous environment?
 

What is dark matter and how does it relate to black holes?

Dark matter is a hypothetical form of matter that is thought to make up about 85% of the total mass in the universe. It does not emit or absorb light, making it invisible to telescopes. Black holes, on the other hand, are regions of space with such strong gravitational pull that nothing, including light, can escape. While dark matter and black holes are both mysterious and have strong gravitational effects, they are not directly related.

Can dark matter turn into a black hole?

No, dark matter cannot turn into a black hole. Dark matter particles are thought to be much smaller than black holes and do not have the necessary mass or density to collapse into a black hole.

Is it possible that dark matter is made up of black holes?

While this is a popular theory, there is currently no evidence to support it. Black holes are thought to form from the collapse of large stars, while dark matter is believed to be made up of unknown particles that do not interact with light. Additionally, the amount of dark matter in the universe is estimated to be much larger than the number of black holes that could have formed from stars.

How do scientists study dark matter and black holes?

Scientists study dark matter and black holes through various methods, including gravitational lensing, observing the movement of stars and galaxies, and detecting signals from space using telescopes and other instruments. While we cannot directly see dark matter, its gravitational effects can be observed on visible matter, providing clues about its presence and distribution.

Are dark matter and black holes related to the expansion of the universe?

Dark matter and black holes do not play a significant role in the expansion of the universe. The expansion is primarily driven by a mysterious force called dark energy, which is thought to make up about 70% of the universe's total energy. While dark matter does contribute to the overall mass of the universe, it does not have a significant effect on the expansion. Black holes, on the other hand, can have a small impact on the expansion, but it is not significant enough to explain the current rate of expansion.

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