How many baryons are there in the universe?

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SUMMARY

The estimated number of baryons in the observable universe is approximately 1080, as derived from calculations in Barbara Ryden's book, "Introduction to Cosmology." This figure represents about 4% of the total energy content of the universe. The discussion highlights the lack of a definitive source for this absolute number, with participants referencing a specific problem solution from a physics course at UCSB to support their claims.

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franoisbelfor
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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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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.
 
Last edited by a moderator:
Coors Cosmology, I like it.
 
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?
 
Chronos said:
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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