04 Apr 14
Scientists are still debating whether dark matter, which provides the elusive missing mass needed to keep galaxies from flying apart, is made of microscopic particles or macroscopic bodies. On the “macro” side, dark matter could consist of relatively small black holes that formed in the early Universe.
http://www.dailygalaxy.com/my_weblog/2013/11/tiny-primordial-black-holes-a-viable-candidate-for-dark-matter.html
A new study of gamma-ray light from the center of our galaxy makes the strongest case to date that some of this emission may arise from dark matter, but black holes also emit gamma-rays.
http://www.sciencedaily.com/releases/2014/04/140403123628.htm
Is eliminating black holes as the dark matter that keeps our galaxy from flying apart premature?
Originally posted by Metal BrainWe on the Spirituality Forum have an answer for what is this invisible so-called "black matter or dark matter" that holds all things together.
Scientists are still debating whether dark matter, which provides the elusive missing mass needed to keep galaxies from flying apart, is made of microscopic particles or macroscopic bodies. On the “macro” side, dark matter could consist of relatively small black holes that formed in the early Universe.
http://www.dailygalaxy.com/my_weblog/2013/11/ti ...[text shortened]... Is eliminating black holes as the dark matter that keeps our galaxy from flying apart premature?
07 Apr 14
Originally posted by Metal BrainMass is mass even if it is the form of black hole.
Is eliminating black holes as the dark matter that keeps our galaxy from flying apart premature?
One million solar masses equal one million sun-like stars, or one black hole with the mass of one million suns. At a distance you cannot tell one from the other only measuring gravitation.
Black holes or not, it is the mass that counts.
07 Apr 14
Originally posted by FabianFnasThis is true, mass is mass and gravity doesn't care where the mass comes from. However, I'm thinking in the case of black holes, the distribution of mass is so concentrated that if the holding together effect of our galaxy and the others, were due to black holes I would think there would be a graininess to the gravitation that would be measurable by astronomers. I think the case is the mass is very diffused and of course black holes would add to the total gravitation of a galaxy I think without the dark matter, if it was only black holes, the distribution of stars around the galaxy would be a lot different, more clumpy than it already is. Also gasses floating around the galaxy would be more clumpy than it is now. At least that is my take on it.
Mass is mass even if it is the form of black hole.
One million solar masses equal one million sun-like stars, or one black hole with the mass of one million suns. At a distance you cannot tell one from the other only measuring gravitation.
Black holes or not, it is the mass that counts.
07 Apr 14
1 edit
Originally posted by Metal BrainStudies of colliding galaxies have shown that dark matter does not interact strongly other than by gravity. For it it be in black holes I think they would have to be relatively few of them for this to be the case. When galaxies collide, the stars tend to pass right through as there is plenty of empty space between them. The gas clouds however collide with each other.
Is eliminating black holes as the dark matter that keeps our galaxy from flying apart premature?
Although it seems there is still some controversy:
http://en.wikipedia.org/wiki/Bullet_Cluster#Significance_to_dark_matter
I don't think however that 75% of the mass of a galaxy could be in black holes that we cannot detect.
07 Apr 14
Originally posted by FabianFnasI agree. Black holes are dark and are dark matter. Some people don't seem to want to conclude that black holes are the form of dark matter that keeps the galaxy together.
Mass is mass even if it is the form of black hole.
One million solar masses equal one million sun-like stars, or one black hole with the mass of one million suns. At a distance you cannot tell one from the other only measuring gravitation.
Black holes or not, it is the mass that counts.
I think ruling out primordial black holes as this dark matter is premature.
07 Apr 14
Originally posted by twhiteheadPrimordial black holes are small black holes.
Studies of colliding galaxies have shown that dark matter does not interact strongly other than by gravity. For it it be in black holes I think they would have to be relatively few of them for this to be the case. When galaxies collide, the stars tend to pass right through as there is plenty of empty space between them. The gas clouds however collide with ...[text shortened]... 't think however that 75% of the mass of a galaxy could be in black holes that we cannot detect.
A spinning black hole drags space around with it and allows matter to orbit closer to the black hole than is possible for a non-spinning black hole.
http://www.sciencedaily.com/releases/2014/03/140305135456.htm
I think Primordial black holes are a significant factor but not the only factor. The universe is expanding at an accelerating pace. I think this may be caused by empty space. In other words "less is more". It is seemingly a contradiction, I know.
https://en.wikipedia.org/wiki/Casimir_effect
07 Apr 14
Originally posted by Metal BrainHow small? What sort of masses? And therefore, what sort of quantities? More than the number of stars or less?
Primordial black holes are small black holes.
A spinning black hole drags space around with it and allows matter to orbit closer to the black hole than is possible for a non-spinning black hole.
I don't think that is relevant.
07 Apr 14
Originally posted by twhiteheadDid you read this link I posted on the OP?
How small? What sort of masses? And therefore, what sort of quantities? More than the number of stars or less?
[b]A spinning black hole drags space around with it and allows matter to orbit closer to the black hole than is possible for a non-spinning black hole.
I don't think that is relevant.[/b]
http://www.dailygalaxy.com/my_weblog/2013/11/tiny-primordial-black-holes-a-viable-candidate-for-dark-matter.html