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Author Topic: What drove early Galaxy formation?  (Read 1582 times)

Offline Fluid_thinker

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What drove early Galaxy formation?
« on: 30/10/2012 15:48:08 »
The first Stars were pristine Hydrogen and Helium massive stars. Being massive stars they would have burned fast and furious and only lasted a few million years.

How did the galaxies form in this environment so fast? (just a few hundred million years after the big bang). Surely, this would be quite difficult with relatively short lived massive stars?

Or was it the sheer volume of these large Stars that influenced the rapid formation? Difficult to see this is the case.

That leads me onto Black holes during the same period. How did they get so big so fast? Was there another factor at play that then drove the Galaxy formation? (This is based on the understanding that Black Holes are slow growing, as they feed fast and exhaust the surrounding environment). They do not appear to have enough time to evolve to the sizes seen.

Therefore, were the first stars considerably more massive than we believe and the Black Holes were born BIG.


 

Offline Soul Surfer

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Re: What drove early Galaxy formation?
« Reply #1 on: 30/10/2012 17:21:42 »
An interesting problem that does not have a definitive answer yet.  Gravitational collapse is a difficult process to simulate and is often counterintuitive in the way it happens.  angular momentum and even residual magnetic fields may have played a part in the process.  In general the collapse appears to happen from the inside out because the smaller distance to fall towards the centre of gravity dominates over the more massive core attractor further out.  As well as large stars that form nucleosynthesis and end in dispersion of material it is also considered that the very largest collapsing masses may have collapsed directly into black holes without ever getting hot or dense enough to start nucleosynthesis. This could then produce the many million to billion soar mass black holes that are seen at the centres of big galaxies. these could drive collapse on a much larger scale that allowed stars to form and reduce the "viscosity" of the medium that enabled collapse in the first place.
 

Offline syhprum

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Re: What drove early Galaxy formation?
« Reply #2 on: 30/10/2012 19:20:11 »
This is maybe a way out suggestion but could there have been numerous "mini big bangs"  that never got to the rapid expansion stage and just collapsed on themselves to form large black holes.
 

Offline evan_au

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Re: What drove early Galaxy formation?
« Reply #3 on: 31/10/2012 10:01:17 »
I have heard that even a small amount of elements heavier than hydrogen can accelerate the rate at which clumps of gas accrete to form protostars.

A cloud of Hydrogen by itself is in a balance between gravitational attraction, and thermal energy which tends to dissipate the cloud, slowing the collapse.

However, heavier elements in the mix allow energy to to be radiated at more wavelengths, allowing the cloud to collapse more quickly.

A first generation of "fast and furious" stars would have seeded nearby space with a variety of heavier elements, which could have accelerated formation of a second generation of stars, with a more familiar size distribution.
http://en.wikipedia.org/wiki/Nebular_hypothesis#Protostars
 

Offline sciconoclast

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Re: What drove early Galaxy formation?
« Reply #4 on: 06/11/2012 15:27:56 »
Not only would the early huge stars seed space with heavy elements but their explosions would have also herder matter into the bubble like filaments that galaxies are confined to.  This was first proposed by Martin Rees.
A Universe of Bubbles and Voids - Sky and Telescope. Vol 80. Issue 3. Page 239. Sept. 1990

The award winning astronomer Halton Arp seems to think that black holes generate new gallaxies by  spewing out jets of matterial of galactic quantities at certain points in their cycle. This of course is contrary to the establish views of what happens in black holes and contrary to established views of galaxy formation. But interestingly he does have a large ctalogue of supporting images. He is way out there in left field but his images are intriguing and worth a look.
Catalogue of Discordant Redshift Associations. C. Roy Keys Inc. 2003     
 

Offline Fluid_thinker

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Re: What drove early Galaxy formation?
« Reply #5 on: 07/11/2012 16:40:37 »
It appears that as we are able to look closer at the earlier galaxies, we are starting to challenge our thinking on the way galaxies got going. It poses many thoughts.

e.g. A slightly varied thought to Syhprum's failed 'mini big bang's'. In a multiverse environment, did out big bang bump into other multiverses causing the acceleration/retardation of the creation of the Galaxies. No need to assume the Big Bang was either creating all space (just our space) or inflating into nothing. The laws of the other multiverses may be very different to ours and therefore influence ours.

Maybe the laws of our own universe do vary at the very edge.
 

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Re: What drove early Galaxy formation?
« Reply #5 on: 07/11/2012 16:40:37 »

 

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