Max Tegmark's library: Q
This work was covered by New
Scientist in November 1997 and by Sky
& Telescope in February 1998 (articles here).
Figure 1: How altering Q changes structure formation
Please click here to get 300K postscript file with
the paper. If you want a color transparency with the figure above, just
print page 8. Click
if you are interested in other research of mine.
Why is the CMB fluctuation level 10-5?
Max Tegmark, Martin Rees
We explore the qualitative changes that would occur if the amplitude Q
~ 10-5 of cosmological density fluctuations were different.
If is less than about 10-6 , the cosmological objects that form
would have so low virial temperatures that they may be unable to cool and
form stars, and would be so loosely bound that even if they could produce
a supernova explosion, they might be unable to retain the heavy elements
necessary for planetary life. If Q is greater than about 10-4,
dense supermassive galaxies would form, and biological evolution could
be marred by short disruption timescales for planetary orbits. If Q were
still larger, most bound systems would collapse directly to supermassive
black holes. These constraints on Q can be expressed in terms of fundamental
constants alone, and depend only on the electromagnetic and gravitational
coupling constants, the electron-proton mass ratio and the matter-to-photon
ratio. We discuss the implications for inflation and defect models, and
note that the recent anthropic upper bounds on the cosmological constant
Lambda would be invalid if both Q and Lambda could vary and there were
no anthropic constraints on Q. The same applies to anthropic bounds on
the curvature parameter Omega.
ApJ, 499, 526-532 (1998), astro-ph/9709058
This site also contains the latest (non-astro/ph) versions of some papers
that are referenced in the text; Tegmark, Silk &
Evrard 1993, Tegmark et al 1997, Tegmark