Nice supercomputer sim of the formation of a small galaxy

[Martin]

There is a short animated film of the formation of a dwarf galaxy, based on supercomputer simulation.

http://www.sciencenews.org/view/generic/id/54015/title/Supernova_winds_blow_galaxies_into_shape

 

In the video you see occasional supernovae exploding, each time blowing away part of the ordinary matter that is trying to gather together. Time is speeded up and the video gradually zooms out, as the small protogalaxy blobs collide, coalesce, as the galaxy grows, and as its spiral structure develops.

 

Finally the galaxy grows massive enough so that its own supernovae do not disrupt it.

 

The animation is part of a proposed solution to a long-standing puzzle about structure formation, published in the current issue of Nature.

http://arxiv.org/abs/0911.2237

 

Dark matter dynamics (with supercomputer simulations) has already explained a lot about structure formation. If you haven't seen this, George Smoot has an excellent 18 minute talk on it---google "Smoot TED".

Earlier simulations successfully reproduced a realistic picture of largescale filamentary (cobwebby) structure of matter, correctly predicted the size and distribution of clusters of galaxies, and the typical shape of individual large galaxies. But the simulations did not give a realistic picture of the dwarf galaxies which have a lower concentration stars and other forms of ordinary matter in their centers than the sims predicted. Overall the dark matter explanation of largescale structure worked remarkably well but there was this nagging discrepancy.

 

The article in Nature addresses that problem and explains the observed appearance and characteristics of a dwarf galaxies.