From: Anders Sandberg (asa@nada.kth.se)
Date: Mon Jul 30 2001 - 02:56:35 MDT
On Mon, Jul 30, 2001 at 01:28:45PM +1000, Miriam English wrote:
> At 12:15 PM 29/07/2001 -0400, Mike Lorrey wrote:
> >Yes, there is. 'Lost' energy must go someplace. Under the steady state
> >theory, the entire universe should be hotter than an EZ-Bake oven.
> >Thanks anyways.
>
> Not necessarily. Two possibilities:
>
> - If the universe is expanding (and there is no reason why some of the
> red shift might not be due to movement) then the universe cools to offset that.
I think that if you do the math, you will find that the universe has to
expand just as fast as predicted by the big bang theory to get rid of
the energy. If you add in continous creation, then it would have to
expand faster to get rid of the extra mass-energy, which makes it even
harder to explain structure formation.
> - If old matter is crushed out of existence in black holes then there is
> no net gain and the universe can be the temperature it is. Conservation of
> energy/mass becomes just a handy guide if you have stuff popping into
> existence in the great voids, or everything all at once at the beginning.
If you start throwing out conservation laws, then you are in trouble.
Then you could just postulate that mass and energy pops into and out of
existence just as you would like it, and become unfalsifiable.
Black holes are rather bad at absorbing heat from the surrounding
universe, since they have small cross sections. Also, since they follow
the matter distribution this explanation would mean an anisotropic
background radiation strongly linked to the matter distribution, which
is not observed to my knowledge.
Black hole thermodynamics says that the horizon area of black holes can
only increase, not decrease. The exception is through Hawking radiation,
but that requires a surrounding universe with very low temperature and
density. In a steady state universe the holes would just grow and grow,
and since you could find black holes of any age, there ought to exist
not just supermassive holes but black holes of arbitrarily large mass -
which we have seen no evidence whatsoever for.
Hmm, thinking of it, the Weyl tensor apparently behaves as a kind of
gravitational entropy. That really ought to be a problem for steady
state cosmology; how did Hoyle get around it?
-- ----------------------------------------------------------------------- Anders Sandberg Towards Ascension! asa@nada.kth.se http://www.nada.kth.se/~asa/ GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y
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