How many baryons are there in the universe?


by franoisbelfor
Tags: baryons, universe
franoisbelfor
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#1
Jul17-09, 09:11 AM
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Many articles and papers say that 4% of all energy in the universe is baryonic. How many baryons does that make? I do not seem to find any wikipedia article or paper that gives an absolute number. Can anybody help?

Thank you!

François
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George Jones
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Jul17-09, 09:41 AM
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Then number of baryons in the observable universe is usually estimated to be about 1080. See, for example, the solution to problem 6.8,

http://www.physics.ucsb.edu/~tt/PHYS133/hws5.pdf,

from Barbara Ryden's excellent book Introduction to Cosmology.
Nabeshin
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Jul17-09, 01:39 PM
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Coors Cosmology, I like it.

Chronos
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Jul18-09, 03:56 AM
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How many baryons are there in the universe?


Good answer, Nabeshin, whatever that meant. Fran asked for a number, George gave the best current estimate. Do you have a rebuttal or are you just sniping?
George Jones
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Jul18-09, 05:22 AM
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Quote Quote by Chronos View Post
Good answer, Nabeshin, whatever that meant. Fran asked for a number, George gave the best current estimate. Do you have a rebuttal or are you just sniping?
The document to which I linked calculates the number, and after the calculation writes:

"*COORS COSMOLOGY*
The number of baryons in the observable universe is roughly equal to the number of
baryons in a bottle of beer, cubed."


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