🚀 go-pugleaf

richmond@spiff.Princeton.EDU (Stupendous Man) writes:

>   Speaking of astronomy, I read the article in today's (Friday's) NY Times
> on a presentation of COBE results from the AAS meeting.  No one here at
> Princeton could figure out what the article was saying.  It SEEMED to
> say something like "COBE measurements of the microwave spectrum show 
> a really, really good fit to a blackbody spectrum.  Therefore, nothing
> exciting happened in the universe after the BB for at least one year."
> Can someone at the AAS meeting make things more clear?
> 

I didn't go to the AAS meeting, but my understanding of the result is
as follows (I'm sure that others will politely correct me if needed :-))

The temperature that COBE sees now is the BB temp, redshifted for
15Gyears (+/- whatever :-) ). If there had been other major releases of
energy (even at the same temp as the Big One) at a later stage they would
have an oh-so slightly different temperature now. Now, I can't draw the
Blackbody curve in ASCII partuclarly well, so pretend it's a triangle :-)

The peak of the triangle depends on the temperature, while the area under
the triangle relates to the energy released in the event. If you see
a temperature profile that looks like a triangle, you can measure its
temp now, and the energy *in that event*. If there are other events, they
will add other triangles, perhaps at other temperatures, and this causes
bumps in your original triangle. If the event was large enough, it will
deform your triangle quite drastically. If it happenened at another temperature
there will be peaks away from the main peak.

The AAS result says that they saw a triangle, and it was a very smooth
triangle - no bumps at other temperatures, down to some very small level. Hence,
if there were other events at a later time they were *very very* small.

Does that help to make it clearer ?  {And to those who know, did I get 
it right ? :-) }

Cheers,
	Markus

-- 
Markus Buchhorn, Parallel Computing Research Facility
email = markus@octavia.anu.edu.au
Australian National University, I-Block, PO Box 4, Canberra, 2601, Australia.
[International = +61 6, Australia = 06] [Phone = 2492930, Fax = 2490747]