I think I would like to respond at this point, not because I am
challenging anybody, but because I don't know enough about this
subject, and hope that, by asking some questions (pertinent or
otherwise), the resultant responses will improve my own level of
understanding.

wrote:
wrote:
Phillip Helbig---remove CLOTHES to reply wrote:

Prediction, prior observation, prediction, assumption later verified by
observation.

By my accounting this list should read:

1. Background Radiation: prediction, but initially off by about 400%
and had to be adjusted to come into agreement with observations.

Your 400% seems way off -- Alpher and Herman's 1948 prediction was "about 5K."

The figure I seem to remember was a factor of 3 difference, but I
certainly couldn't quote references after all this time. I would guess
from the above that various people had a stab at this calculation, with
differing results. If so, cherry picking the best, after the fact,
would seem to be no more logical than cherry picking the worst.

Furthermore, you're not quite asking the right question. CMBR temperature
varies with time, so to predict the value "now" you need to know when "now"
is,

I don't think anyone could argue with that.

relative to, say, primordial nucleosynthesis.

Clarification here would be appreciated. I was under the impression
that CMBR is black body radiation at the transition from plasma physics
to the point where protons and electrons combine to form atomic
hydrogen, thus indicating the temperature at which this transition is
believed to take place.

Remember also that the prediction was not just a temperature, but a spectrum.
Black body spectra are hard to make (since temperatures of different sources
get different red shifts);

Hmm. Black body radiation is black body radiation, isn't it?. Different
elements give different spectra because of bound electron transitions.
Any plasma should give the same BB spectrum (with the peak intensity
defining the temperature of that plasma).

the observation of not only the temperature but
the spectrum is a very strong confirmation.

Surely observed intensity is at least as important?

You shouls also add a number of other predictions:

-- red shift dependence of CMBR temperature (for observations, well after the
predictions, see Battistelli et al., astro-ph/0208027; Srianand et al.,
astro-ph/0012222; Molaro et al., astro-ph/0111589)

Yes, that certainly confirms global expansion (which I don't think
anybody doubts). However, I dont see how this necessarily nails things
down any more precisely. Take, for example, Oh No's theory (which I am
definitely not claiming to support). In this you should still get such
changing T with changing z despite the timescales being radically
different.


John Bell
(Change John to Liberty to bypass anti-spam email filter)