ethan@utastro.UUCP (Ethan Vishniac) (05/16/84)
[In the beginning was the word, and the word was tenure] D. Gwyn writes: >Here is my favorite cosmology: > (1) Space isotropic (same, on a large scale, in all directions). > (2) Distant light red-shifted `a la Hubble. > (3) Therefore, light is "infinitely" red-shifted in the limit > that it originates from a certain large distance (call it > the "radius of the universe" for definiteness). > (4) The local average density of matter etc. is static (does > not change in time). > (5) The above all apply to every point in the universe, at > every time. I have mentioned elsewhere why the essential elements of this cosmology fail to explain our observations of the universe. In this note I just want to note an apparent paradox in this model that Mr. Gwyn has not addressed. Perhaps he has something in mind. Stars can be considered as machines for manufacturing entropy. To put it more exactly, they take a lot of hydrogen and make it into heavier elements. The photons produced from this are casually strewn across the cosmos. If the universe is not expanding, and is steady state, then it would appear that the material in the universe will gradually be made into heavy atoms (ultimately isotopes near Fe56). This is certainly not a universe which is constant in time. Gwyn's universe seems to require some form of magic to undo the increase in entropy caused by the stars. An example of such an engine would be to say that the tooth fairy goes around breaking apart the heavier elements down into hydrogen. In our own galaxy we see this process (the increase in entropy, not the appearance of the tooth fairy) in that the oldest stars are almost pure hydrogen and helium. Younger stars, formed from an increasingly contaminated interstellar medium, can have as much as 4% heavier atoms. Our own sun has about 2%. "Just another Cosmic Cowboy" Ethan Vishniac {ut-sally,ut-ngp,kpno}!utastro!ethan Department of Astronomy University of Texas Austin, Texas 78712
gwyn@brl-vgr.ARPA (Doug Gwyn ) (05/17/84)
I don't have any specific model in mind to explain why the whole universe doesn't turn into iron eventually, but I should note that this question did not bother too many cosmologists before the Big Bang Bandwagon either. If I had ALL the answers to questions like this I would go collect my Nobel prize rather than work as a civil servant... Maybe the answer lies in the fact that energy is not strictly conserved. Perhaps there is something to the steady-state theory after all. Why doesn't one of you establishment cosmologists work up a clear disproof of this possibility; it would strengthen your case. There is a large list of commonly-accepted (these days) ideas in physics and especially cosmology of which I am not convinced (after graduate training in Physics and much reading of the technical literature). Maybe the discussion could be steered toward an investigation of the evidence for: neutron stars black holes renormalization methodology quarks and other unobservable building blocks magnetic monopoles gravitational radiation gravitons