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Is all of this accounted for in the "missing mass" of the observable universe? In other words, could those unseen before stars explain a part of the dark matte

Is all of this accounted for in the "missing mass" of the observable universe? In other words, could those unseen before stars explain a part of the dark matter problem?

antognini 12y ago
Not really. Dark matter makes up so much more of the Universe (~25% dark matter vs. 5% baryons -- stars themselves are closer to .2%) in that even doubling the number of stars would not appreciably change the amount of missing mass. Moreover, dark matter has a different signature on the CMB than ordinary matter does, so you cannot solve the dark matter problem by adding ordinary matter---dark matter has to be something fundamentally different. There is, however, a problem called the "missing baryons problem." Measurements of the CMB predicts a certain amount of ordinary matter in the universe, but the amount of matter observed is too small by a factor of about 2. It is possible that these stars could contribute to the missing matter in this problems. (It probably would not be the stars directly, but a tenuous gas from which the stars formed.)
Florin_Andrei 12y ago
No, dark matter is something that happens within galaxies, affecting their rotation. It's not something outside.
- db48x 12y ago
  Sorry, that's wrong. Matter, dark or otherwise, is scattered throughout the universe, with variations in density at all scales. Ordinary and dark matter are gravitationally attracted to each other, so they clump together. Anywhere you find matter you'll find a proportional amount of dark matter, on average; naturally there are variations. There's some in between you and your computer monitor right now. The first good indication that dark matter must exist was in fact that the rotation rates of the observable galaxies were too large for the amount of visible mater they contain. Of course the first explanation was that this matter was ordinary gas, dust, rocks, planets (which are just larger dust particles, when compared with the size of even a small galaxy.), etc that wasn't emitting any light. However, there would have to be so much of it that it would occlude the distant galaxies, something that obviously isn't happening. Thus the modern theory is that dark matter is a form of matter that interacts gravitationally with ordinary matter, but has no interaction with the electromagnetic force (light).

Is all of this accounted for in the "missing mass" of the observable universe? In other words, could those unseen before stars explain a part of the dark matter problem?

antognini 12y ago

Not really. Dark matter makes up so much more of the Universe (~25% dark matter vs. 5% baryons -- stars themselves are closer to .2%) in that even doubling the number of stars would not appreciably change the amount of missing mass. Moreover, dark matter has a different signature on the CMB than ordinary matter does, so you cannot solve the dark matter problem by adding ordinary matter---dark matter has to be something fundamentally different. There is, however, a problem called the "missing baryons problem." Measurements of the CMB predicts a certain amount of ordinary matter in the universe, but the amount of matter observed is too small by a factor of about 2. It is possible that these stars could contribute to the missing matter in this problems. (It probably would not be the stars directly, but a tenuous gas from which the stars formed.)

Florin_Andrei 12y ago

No, dark matter is something that happens within galaxies, affecting their rotation. It's not something outside.

db48x 12y ago
Sorry, that's wrong. Matter, dark or otherwise, is scattered throughout the universe, with variations in density at all scales. Ordinary and dark matter are gravitationally attracted to each other, so they clump together. Anywhere you find matter you'll find a proportional amount of dark matter, on average; naturally there are variations. There's some in between you and your computer monitor right now. The first good indication that dark matter must exist was in fact that the rotation rates of the observable galaxies were too large for the amount of visible mater they contain. Of course the first explanation was that this matter was ordinary gas, dust, rocks, planets (which are just larger dust particles, when compared with the size of even a small galaxy.), etc that wasn't emitting any light. However, there would have to be so much of it that it would occlude the distant galaxies, something that obviously isn't happening. Thus the modern theory is that dark matter is a form of matter that interacts gravitationally with ordinary matter, but has no interaction with the electromagnetic force (light).