From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: No big crunch?
Organization: University of Virginia
Date: Thu, 5 Nov 1992 21:10:58 GMT

In article <5NOV199210450757@csa2.lbl.gov> sichase@csa2.lbl.gov (SCOTT I CHASE) writes:
>In article <1d9lptINN94@agate.berkeley.edu>, ted@physics3 (Emory F. Bunn) writes...
>>In article <1992Nov4.203930.20410@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
>> I prefer pixies.
>>(Stuff deleted.) 
>>I said:
>>>>Dark matter, in contrast, seems qualitatively to explain what's observed
>>>>without any completely outrageous new physics.
>>>
>>To which Dale replied:
>>>     Except, of course, for the completely outrageous production of 
>>>     unknown matter.
>
>[...Ted's response deleted...]
>
>I would like to support Ted's comments by adding that I can't imagine
>any particle physicist who would argue that we have identified the
>complete spectrum of fundamental particles.   HEP is a very young science.
>It's amazing, IMHO, that we have been able to arrive at any kind of 
>synthesis in so short a time.  But having achieved this with the Standard
>Model, we should not draw the conclusion that all that's left is dotting
>the i's and crossing the t's. 

     Though I am a bit surprised by this statement since I believe you have,
     in the past, posited that there was very little fundamental left
     to discover, I do agree.  However, basing one's cosmology on the 
     *requirement* that new, unknown matter actually comprises most
     of the known universe seems extremely speculative.  

>I think that it is far from "outrageous" to speculate that there are 
>vast amounts of "unknown", a.k.a. nonbaryonic matter in the Universe.  In
>fact, questions of abundance aside, I regard it as likely that other

     I did not say that such *speculation* was outrageous, it was the
     *production* that seems outrageous.  I would be perfectly happy
     if all discussions of nonbaryonic dark matter were preceeded by 
     the statement that 'this is extremely tenuous speculation'.

     After all, apparently HEP theorists did not do a very good job
     extending the Standard Model to predict the top mass.  Why should
     we take as anything but doubtful fancy the tenuous speculative
     extentions that predict such things?

>forms of matter do exist.  I think it would be both presumptuous and 
>a bit naive to think that at this early stage in our understanding of
>the high-energy world that nothing fundamentally new will show up.

      I agree.  That doesn't imply that we are awash in the fundamentally
      new. 

>One reason that the dark matter hypothesis is so popular is that it is
>so straightforward to test.  Conversely, long-range modifications to GR
>are very messy to study in the lab.  Dark matter searches, now just
>starting, are a natural extension of our decades long experience with 
>cosmic ray physics - looking up into the sky to search for particles raining
>down on us.  Much of what we know about particle physics comes from this
>avenue of research.   

      More appropriately, much of what we *don't* know seems to come
      from this avenue.  Gamma ray bursters and extremely high energy
      particles come directly to mind.

      However, how easy it is to test is a matter of debate.  I suspect
      that I could invent a dark matter distribution of various forms
      of dark matter with different interactions that would pass any and
      all observational tests.  I would be happy to hear differently,
      but I'm not holding my breath.

>The possibility that dark matter dominates the Universe has reminded 
>physicists that we have never really studied "cosmic ray" physics with
>the kind of completeness that it deserves.  We have almost completely 
>ignored the possibility of weakly interacting particles in the cosmic
>radiation.  We have been entirely preoccupied with charged particles, which
>are easily studied using emulsions and plastics.  Now we have embarked
>on a program to search for other types of particles, which if successful
>will surely revolutionize particle physics, even if the things that are
>found end up having no significance in explaining galactic rotation curves
>and other problems with large scale gravitation.

     I agree.  How about making $400 million a year available, and
     we'll let y'all have $40 million for cosmic ray research?  I suspect
     the concrete requirements (pun intented) for cosmic ray research
     are somewhat lower than SSC.

                           dale bass

-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
Newsgroups: sci.physics