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Author Topic: Did Dark Matter make the early Universe uneven?  (Read 830 times)

Offline lukaradulovic

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Did Dark Matter make the early Universe uneven?
« on: 12/01/2016 16:13:58 »
So, i was watching a documentary about the history of the Universe, and they said that immediately after the Big Bang happened, matter and energy started to spread unevenly, and that's what caused gravity to do it's work in forming the first stars and galaxies. So, my question here is: Could it be that the unevenness of that spread was actually caused by the gravitational force of dark matter? If so, wouldn't that mean that dark matter might be older than the Universe itself?
« Last Edit: 13/01/2016 14:11:43 by chris »


 

Offline evan_au

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Re: The Big Bang and Dark Matter
« Reply #1 on: 13/01/2016 08:35:31 »
Quote from: lukaradulovic
the unevenness of that spread
In any hot gas or plasma, there will be statistical fluctuations in density; this applies to the Big Bang too. Over time, these fluctuations could result in some areas clumping together to form stars and galaxies.

Regardless of whether Dark Matter was created in the Big Bang, or was present before the Big Bang, it too would have statistical fluctuations in density, which could contribute to the formation of galaxies.

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gravity to do it's work in forming the first stars and galaxies
We aren't really sure what Dark Matter is, but one of the more popular theories is that it is some form of Weakly Interacting Massive Particles ("WIMPS"); if so, it would not contribute greatly to the formation of stars, as formation of the first protostars requires hydrogen to aggregate, and radiate away the resulting energy as light, allowing the aggregate to condense into stars. The hypothetical WIMPS would not interact strongly with each other to aggregate, and could not radiate their energy away as light, and so could not condense to assist the formation of stars.

However, studies of Dark Matter haloes around galaxies suggests that perhaps galaxy clusters formed around concentrations of Dark Matter (whatever it is).
 

Offline jeffreyH

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Re: The Big Bang and Dark Matter
« Reply #2 on: 15/01/2016 17:01:44 »
However, studies of Dark Matter haloes around galaxies suggests that perhaps galaxy clusters formed around concentrations of Dark Matter (whatever it is).

Now that is quite an interesting point. Considering that galaxies appear to have super massive black holes at their centres. A very large concentration of dark matter, enough to start galaxy formation, may well have produced these black holes as they now are rather than them growing over time. Since the orbits of objects around a forming black hole would not change as the matter compressed it seems unlikely that any significant portion of the central mass of the galaxies would have contributed much to their central black holes.
« Last Edit: 15/01/2016 17:04:10 by jeffreyH »
 

Offline alysdexia

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Re: Did Dark Matter make the early Universe uneven?
« Reply #3 on: 17/01/2016 18:08:07 »
However, studies of Dark Matter haloes around galaxies suggests that perhaps galaxy clusters formed around concentrations of Dark Matter (whatever it is).

Galactic collisions can make dark matter, these neutralinos which I think is gravitally fusede Planck matter.

Now that is quite an interesting point. Considering that galaxies appear to have super massive black holes at their centres.

No they don't.
 

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Re: Did Dark Matter make the early Universe uneven?
« Reply #3 on: 17/01/2016 18:08:07 »

 

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