Elemental Puzzle

[chalsall]

Originally Posted by xilman

Incidentally, at even earlier epochs (again in the hot BB model) the temperature was so high that even protons and neutrons were evaporated back into their constituent quarks and gluons as soon as they formed. There wasn't even hydrogen at that time.

That epoch has been estimated as lasting how many milliseconds after the theoretical BB?

[xilman]

Originally Posted by chalsall

That epoch has been estimated as lasting how many milliseconds after the theoretical BB?

Left as an exercise for the reader.

It's a fairly easy exercise. The temperature scales as 1/t where t is the age of the universe. For present purposes, take the universe to be 10 gigayears old and 3K in temperature. The mass-energy of a nucleon is 1GeV (again to adequate precision). Calculate the temperature at which the black body photons would have typical energies of this magnitude and proceed to compute the age of the universe when the CBR had that temperature.

You will need to dig out the relevant formulae and the values of the required fundamental constants before you can get a numerical value good to an order of magnitude or so.

[chalsall]

Originally Posted by xilman

Left as an exercise for the reader.

You missed my point. Or, at least, pretended to do so....

[cheesehead]

Originally Posted by chalsall

You missed my point. Or, at least, pretended to do so....

Once in a while, you're just a bit too terse for unambiguity. :-)

[xilman]

Originally Posted by chalsall

You missed my point. Or, at least, pretended to do so....

Guilty as charged.

It's still a good exercise though. Quite a bit of cosmology isn't anywhere near as difficult as popular mythology would have us believe.

[chalsall]

Originally Posted by xilman

Quite a bit of cosmology isn't anywhere near as difficult as popular mythology would have us believe.

Agreed.

[cheesehead]

Originally Posted by cheesehead

Once in a while, you're just a bit too terse for unambiguity. :-)

... but we cherish your contributions anyway. :-)

[davar55]

Originally Posted by cheesehead

... but we cherish your contributions anyway. :-)

Certainly. The big bang theory's explosion and the subsequent
scattering and coalescing of smaller particles into larger ones
and eventually stars and black holes and galaxies, would be an
accurate description if applied to a portion of the universe,
but not the whole universe all at once. That would be to me
arguably impossible. That's why I asked my ^^^ question
about other than HRS evidence. I thought the issue,
whether the bb was real, needed a contrasting intelligent
viewpoint.

[xilman]

Originally Posted by chalsall

You missed my point. Or, at least, pretended to do so....

Nonetheless, it's an exercise well worth doing. Any takers? TW, RDS and EWM are obvious candidates who shouldn't find it in the least bit difficult but it really is within the reach of anyone who can Google for the formulae and constants and then perform order-of-magnitude computations.

[chalsall]

Originally Posted by xilman

Nonetheless, it's an exercise well worth doing. Any takers?

Empirically, the "Press" are willing to take it on.

As an example, CNN....

[cheesehead]

Originally Posted by davar55

but not the whole universe all at once. That would be to me arguably impossible.

Why not? What's the "portion" size that separates possible from impossible?