Mass of the Universe: What's the Real Number?

[diogenesNY]

An actual number for the mass of the observable U

Just to put a cit-able number on the OP's question:

I called up http://www.wolframalpha.com in a browser window.

in the _search term_ box I entered the following: What is the mass of the observable universe

Wolframalpha's response, cited as 'calculated by Wolfram Mathematics' was as follows:

~~ 3.4×10^54 kg (kilograms)

~~ ( 2×10^(-6) ~~ 1/600000 ) × high end for estimated mass of the universe (~~ 2×10^60 kg )

~~ 10000 × low end for estimated mass of the universe (~~ 3×10^50 kg )

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I make no representations about the validity of the above information except that it is accurately transcribed and is from a publicly accessible source.

diogenesNY

 

[Chronos]

We've even calculated the number of atoms, even Planck areas, in the observable universe. Those are some big numbers. All such calculations require debatable assumptions.

 

[Trenton]

Dark matter is virtually collisionless, even with itself, hence it does not clump in stars, or pretty much anything else. It tends to be most abundant in halos because it continuously yo-yo's in and out of the galaxy, and that is where it's velocity is minimal.

Been out of the loop for a while but on this issue, obviously any dark matter outside a formed star would simply fall in, gain speed and then re-escape. But this would be less the case when a gas cloud was coallescing into a star.

I remain open on dark matter but I also remain convinced that a lot more of the unaccounted for mass is baryonic. Correct me if I am wrong but as I understand it, LSB galaxies appear to be some 20 times as massive as their luminoscity would suggest rather than 5 or 6 times for a typical galaxy. Yet why would there be any dramatic difference in the ratio of dark matter to baryonic matter in the original gas clouds?

I know we can see hydrogen gas thanks to the 21cm line but how much of it can we see? I am having a lot of difficulty finding descriptions of how to calculate the output at 21cm per Kg of hydrogen, under typical interstella conditions. On top of this are our estimates of the metalicity of interstella gas wrong?

I shall leave with a question that is related to this issue. I was told once by a lecturer, that the different elements were assumed to be evenly distributed throughout a star - rather than have the heavier elements sink to the center. Is this still thought to be the case?