Re: [asa] big bang question ... and the start of matter...

David -

It depends in part by what is meant as "the big bang." When cosmologists say that the big bang model has been confirmed they mean that our observations agree with the present expansion of the universe back to a state of very high temperature & density. We can "see" (with microwaves) back to something like 350,00 years after "t = 0" & the helium-hydrogen ration takes us back to a few minutes. Particle theories in which we have considerable confidence can carry us back to a small fraction of a second. But earlier than that the theories become very speculative. There is a fair amount of evidence for inflation, & that gets us much closer. But we know that classical models with realistic forms of matter have a singularity. The reason I put t = 0 is that the singularity is not just an event at which strange things happen. It's not there! It's really space-time that's singular in the sense that it's incomplete - as if a point were ripped out of it.

We know, independently of cosmology, that Einstein's gravitational theory has to be quantized & it's possible that a consistent quantum theory won't have a singularity, but that's not certain. Some such theories, like the one I mentioned of Vilenkin's, try in a sense to get "before t = 0," though the meaning of that is ambiguous. Although such theories are very speculative & as yet have no observational confirmation, it's not impossible that there could be relevant observational data in the future - e.g., in the pattern of fluctuations in the microwave backgroun &/or gravitational waves from the early universe. So it's a bit too strong to say that such work is not scientific.

At present our understanding of the early universe is consistent with Christian belief in the creation of a universe "not in time but with time." This is especially the case if the mathematical pattern of the universe is connected with the Logos concept of the 4th Gospel. I would definitely not, however, want to describe this in terms of an "unmoved Mover" since our ability to understand the origin of the world as well as we do points to a divine kenosis in creation that anticipates the passion of God.

You might be interested in a recent article of mine in Covalence at http://archive.elca.org/faithandscience/?Copyright=08-04-17&Author=murphy&Pages=1.asp - it's the talk I gave at the Sunday Scientist Conference last fall in Arizona.

Shalom
George
http://web.raex.com/~gmurphy/
  ----- Original Message -----
  From: David Opderbeck
  To: George Murphy
  Cc: asa@calvin.edu
  Sent: Tuesday, May 06, 2008 11:28 AM
  Subject: Re: [asa] big bang question ... and the start of matter...

  George, in lay terms, is the following true:

  -- what was "before" the big bang appears at present to be a true singularity ("before" not really being an appropriate term because space-time does not exist before the big bang). Science at present cannot explain what was "before" the big bang and it appears that science may never be able to do so within the bounds of known principles of physics. Common scientific explanations presently involve ideas such as string theory, bouncing universes, colliding branes, and/or multiverses, none of which are properly scientific theories because they are not really testable.

  -- in theological / apologetic terms, the singularity "before" the big bang seems consistent with the notion in classical Christian theology that the universe had a "beginning" caused by an unmoved mover God. Though this is a god of the gaps argument, it is a more sturdy argument than irreducible complexity in biology, because pre-big bang singularity appears to be a real black box. However, it is not impossible that this black box also could be opened, so the question of creation's exact "beginning" and the strength of unmoved mover / Kalam arguments must be held with some degree of tentativeness.

  On Tue, May 6, 2008 at 11:08 AM, George Murphy <gmurphy@raex.com> wrote:

    I should probably clarify what I said below. In the simple model I described, in which 2 particles pop into existence in a state of zero energy, the speeds of the particles will decrease as their separation increases until they come to a stop & then fall back together. (There can be no orbital angular momentum if the particles are spinless.) This can be seen by solving the special relativity equation of motion with Newtonian gravity. In this sense the model corresponds to the closed universes of general relativity.

    But in relativistic cosmology things are different. The Friedman equation for the scale factor of a uniform model universe has the mathematical form of the Newtonian - i.e., nonrelativistic - equation of motion of a particle. (This resuult seems surprising but there's a reason for it. In a uniform universe the scale factor of any small part is the same as that of an arbitrarily large part. & for a sufficiently small region containing a very small amount of matter, the equations of Einstein's theory approach those of Newton's.) What corresponds to the Newtonian energy is -kc^2/2 where k is the curvature which is +1 , -1 or 0. So zero "energy" corresponds to flat space, the borderline between spaces which will expand forever and those which will eventually collapse. k = 0 is like the case of a rocket sent away from the earth at exactly escape velocity - it would in the limit creep out to infinity at a speed approaching zero but would never fall back.

    Both inflationary cosmology and present observations indicates that our universe is, on the average, spatially flat. But it's possible that it's a closed (spherical) space with an extremely large radius of curvature.

    Shalom
    George
    http://web.raex.com/~gmurphy/
      ----- Original Message -----
      From: George Murphy
      To: Dehler, Bernie ; asa@calvin.edu
      Sent: Monday, May 05, 2008 6:04 PM
      Subject: Re: [asa] big bang question ... and the start of matter...

      Bernie -

      Briefly, matter could come into existence from a state of zero energy if its mc^2 energy plus any kinetic energy were exactly cancelled by its negative gravitational potential energy. In the simplest case of 2 particles of mass m at a distance r, 2mc^2 - Gm^2/r = 0. In a more general case of a homogeneous distribution of matter, this corresponds to the spatially closed universes of Einstein's theory. The transition from a state of no particles to one of 2 (or of N) particles would be discontinuous but quantum theory allows such "jumps." Thus you need a correct quantum theory of gravitation to make this work rigorously & whether we have that or not is a matter of debate.

  --
  David W. Opderbeck
  Associate Professor of Law
  Seton Hall University Law School
  Gibbons Institute of Law, Science & Technology

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Received on Tue May 6 12:27:40 2008