From: Robert J. Bradbury (bradbury@www.aeiveos.com)
Date: Thu Oct 21 1999 - 22:31:47 MDT
Amara provided a nice condensed version of nucleosynthesis 201.
Since I've been wrestling with the Dark Matter question since
Extro3, my living room coffee table is buried under a number
of references, including:
100 Billion Suns, Rudolf Kippenhahn
Structure and Evolution of the Stars, Martin Schwarzchild
Stars and Their Spectra, James B. Kaler
Stellar Evolution, Amos Harpaz
Galactic Astronomy, James Binney & Michael Merrifield
Dark Matter, Missing Planets & New Comets, Tom van Flandern
and
Nucleosynthesis and Chemcial Evolution of Galaxies, Bernared E. J. Pagel
(which IMO is probably the best of the bunch).
So most of the nucleosynthesis process I'm generally aware of,
though not to the level of detail you discuss.
You wrote:
>
> Why is nucleosynthesis like this in our universe ?
> (I don't know the answer to that)
This was really more the point of my previous comment. Dyson
pointed out in several places the degree to which some of the
fundamental constants & forces are constrained to produce the
universe we see.
The question of why nucleosynthesis doesn't produce Li, B, or Be
in much abundance is related to this.
>
> So you see, an important feature in understanding nucleosynthesis is
> the energetics of fusion, as determined by the atomic mass excesses
> and the mean binding energy per nucleon. "boron" doesn't have the
> right atomic and binding energy to fit in the scheme of the
> nucleosynthesis processes (P-P chain, CNO chain), and so you see how
> carbon is a natural fusion product of heavier stars.
But *why* does B not have the proper binding energy?
Why does the second most common nuclear reaction in stars produce
material that is great for creating soft & hard nanotech?
Now, of course I could argue it the other way -- why isn't
the 1st most common reaction in stars the one that produces
the energy *and* the material for the building blocks of
thinking machines. Sounds like we got put in the "discount"
universe product aisle. Not the best set of reactions and
evolutionary paths but not the worst either.
Or is there some hyper-structure to the laws of how universes
can be structured that says we got the best that is available?!?
Have any serious physicists sat down and designed universes
with physical constants that would have much better or worse
properties than our own? [Sounds like a way to manufacture
many Physics PhDs, just as "clone & explain" a gene is now
doing in molecular biology...]
Robert
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