Found the Baryons: they're ionized

Robin Hanson (
Thu, 15 May 1997 09:37:08 -0700 (PDT)

A big week for astrophysics!

Science 9May97 p.899 describes an article in the current Astrophysical
journal, which gives a plausible theory of where all the baryons are,
and of the Lyman-alpha forest of Quasar absorption lines.

Simply assume a log-normal distribution of density in the universe,
which is consistent with simulations and simple theory. Given lots of
ambient hard radiation, such as from quazars, the low density rgions
are highly ionized, and so are transparent to ordinary light.
Fitting this model to actual Quasar absorption lines can account for
all the baryons expected from primordial nucleosynthesis.

So now we just need to find out what/where the non-baryonic dark
matter is.

Robin D. Hanson