[ExI] Dark doubts

Gregory Jones spike66 at att.net
Thu Jun 17 19:52:57 UTC 2010

--- On Thu, 6/17/10, Damien Broderick <thespike at satx.rr.com> wrote:
From: Damien Broderick <thespike at satx.rr.com>
Subject: [ExI] Dark doubts
To: "ExI chat list" <extropy-chat at lists.extropy.org>
Date: Thursday, June 17, 2010, 8:45 AM

On 6/17/2010 1:14 AM, Gregory Jones wrote:

>  >   What about the 96% of all that is that isn't atoms and photons?  - s
> We lose that.  For now...

Maybe it's not even there:

Doubts about universe's dark side
Thursday, 17 June 2010

by Heather Catchpole
Cosmos Online

SYDNEY: Errors in the way physicists estimate the effects of dark matter and dark energy on the leftover heat from the Big Bang has thrown their existence into doubt, say British scientists...
Hmmm, OK but have ha' me doots about their doots.  Read on please sir:

>Physicists' general model of the universe includes two 'dark' concepts...
Ja, at least two.

>...Dark energy is a force that explains the way that galaxies accelerate away from each other, while dark matter was postulated to explain the observations that galaxies have more mass than can be accounted for by stars and gas...
An then the article goes on to discuss primarily the first, but not the second.  I can find almost nothing in the article that says much about the second concept, even tho that is the one I find by far the most compelling for the existence of dark matter.  Evidence for dark matter wasn't initially from anisotropy in the cosmic background radiation.  The astro-physics community didn't really even start getting really serious about that until about 1991 (after the launch and data came back from the Cosmic Background Explorer satellite COBE (another Lockheed Martin product (for which the CG and balance metrology effort was performed by your humble servant.)))

>Evidence for the 'dark side' comes primarily from studies of the Cosmic Background Radiation (CMB), the leftover 'glow' from the Big Bang, which has been analysed in detail by the Wilkinson Microwave Anisotropy Probe (WMAP), a NASA satellite telescope launched in 2001 that provided the first full-sky map of the CMB...
WMAP schMAP.  COBE provided a full-sky map of the CMB a decade earlier.  But I digress.
To me there is a stronger line of evidence for dark matter, or rather a line of evidence for which there are fewer alternate explanations than the surprisingly low entropy in the cosmic background radiation (a finding which is really cool and interesting for sure.)
The other concept the article mentions but doesn't talk about is the anomalous mass distribution of galaxies.  Forget inflation models for a moment, forget that the universe appears to be right on the edge between open and closed.  Something might be way terribly wrong with all our notions on that.  But we can look at stars in a galaxy, and measure the rate at which the stars on one side are coming, and how fast the stars on the other side are going, subtract out the relative velocity of the galaxy with respect to the observer and we see an interesting sight.  The velocity falls off more gradually than we would expect, if we assume all the matter is visible in the form of stars.  The velocity distribution indicates there is one hell of a lot of matter in there somewhere that isn't shining and isn't blocking light.  What we see is not what we get.
That being said, I argue that we are not necessarily forced to postulate some exotic mysterious dark stuff, no weirdinos or bizarrons needed.  The extra matter can be plain old familiar matter, mostly cold hydrogen, with perhaps a bit of metal mixed in (he said hopefully.)  Then there is something waaay wrong with our notions galaxy formation, but not with our instruments.  
Cosmology is a giant crossword puzzle.  We have all gotten blocked where we know either this word or that word must be wrong.  Well, it could be that both those are right, and another nearby word that was never suspect is wrong instead.  Fix that, and everything fits.  Likewise with cosmology, we must keep an open mind, and always recheck everything.  
The bug-in-galaxy-formation-theory explanation easier for me to believe than the alternate explanation offered by the Shanks group.  I am not tossing my astronomy texts into the trash yet.
Stay tuned, and keeeeep looking up.  {8-]
Is this a cool time to be alive, or what?  {8^D


From: Damien Broderick thespike at satx.rr.com

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