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Fraser
2004-Sep-23, 04:58 PM
SUMMARY: Astronomers have been studying the deepest optical view of the Universe - the Hubble Ultra Deep Field (HUDF) - and they think they've found some of the first star forming galaxies. These galaxies began forming 0.5 to 1 billion years after the Big Bang. The team analyzed the HUDF, and found dozens of red, dim dwarf galaxies, which appear to be the first basic galactic building blocks. These would merge with other galaxies to eventually form the complex spiral formations like our own Milky Way. The also found regions which were more dense than others, which supports the theory that dense regions of space where the first places galaxies formed.

What do you think about this story? Post your comments below.

om@umr.edu
2004-Sep-23, 06:51 PM
Another great story, Fraser.

I was unable to find if the composition of the material they see, at 95% of the time back to the "Big Bang", matches the composition of "primordial Big Bang products"?

Or do they find Fe, O, Ni and Si that were supposedly produced later?

With kind regards,

Oliver
http://www.umr.edu/~om

StarLab
2004-Sep-23, 07:06 PM
The also found regions which were more dense than others, which supports the theory that dense regions of space where the first places galaxies formed.I think that's logical.

Ola D.
2004-Sep-23, 07:15 PM
How much dense is our galaxy? Is it among the most dense?

antoniseb
2004-Sep-23, 10:38 PM
Originally posted by Ola D.@Sep 23 2004, 07:15 PM
How much dense is our galaxy? Is it among the most dense?
Our galaxy, including its halo, appears to have a mass of about 6x10^44 grams, which would be about 4x10^68 atoms since it is mostly Hydrogen.

It has a volume of 4x10^67 cubic centimeters [counting the disk and bulge, but not the halo] So, including stars, dust, black holes, dark matter, etc, the galaxy has a density of about 10 protons or neutrons per cubic centimeter.

This is roughly the same as most nearby galaxies with central bulges.

StarLab
2004-Sep-23, 11:33 PM
Yeah, Ola, it's pretty avg.

om@umr.edu
2004-Sep-24, 06:00 PM
Density doesn't provide the kind of quantitative information we need to deciper this observation.

We need to know if the composition of the material is He and He, as expected for the composition of "primordial Big Bang products"?


Or does it contain more evolved matter with Fe, O, Ni and Si?

With kind regards,
Oliver
http://www.umr.edu/~om