Re: Remarkable unity

Concerning Don's point below, electrons & photons do contribute to what's called loosely the "baryon" energy density. But since there's 1 electron per proton & the electron mass is ~1/1840 the proton's, the correction is small. There are lots more photons in the MWB by ~10^9 than baryons, but the energy of a 2.7K photon is only ~ 2 x 10^ -4 eV compared with ~ 10^9 ev for a baryon.

Some earlier posts on this thread missed the point, which is not that the densities of baryons, dark matter & dark energy of add up to some mysterious number 1. Rather, it's that these densities add up (pretty closely) to the critical value required for space (not space-time) to be flat, 3H^2/8*pi*G where H is the present value of the Hubble parameter ("Hubble constant"). (This is the critical mass density. The critical energy density is that multiplied by c^2.) Of course this can then be stated as a dimensionless ratio, the total density divided by the critical density.

Shalom
George
http://web.raex.com/~gmurphy/
  ----- Original Message -----
  From: Don Winterstein
  To: ASA ; Jim Armstrong
  Sent: Monday, April 18, 2005 7:45 AM
  Subject: Re: Remarkable unity

  Jim Armstrong wrote:

  "...Three important density parameters
  were derived from the CBR data:
      1. the total baryon energy density ...
      2. the so-called dark energy.....
      3. the energy associated with the exponential portion of the
  universe's expansion....
  These three things encompass all we know to exist of have effect in the
  universe. "

  Don't wanna nitpick, but I always thought electrons were fairly important, and maybe even photons. Guess it's a matter of perspective. : )

  Don

    ----- Original Message -----
    From: Jim Armstrong
    To: ASA
    Sent: Saturday, April 16, 2005 10:30 PM
    Subject: Remarkable unity

    Vern, in a recent lecture by Dr. Rogier Windhorst, one of the
    astronomers who is involved in the acquisition and analysis of the
    Hubble Space Telescope images, he spoke briefly about a result I thought
    might be of interest to you. This result actually comes out of the
    Cosmic Background Radiation data analysis that ultimately yielded the
    universe age of 13.7 billion years. Three important density parameters
    were derived from the CBR data:
        1. the total baryon energy density (the energy and material
    equivalents of the stuff we know about) .
        2. the so-called dark energy that corresponds to stuff whose
    presence is clearly indicated, but about which we know virtually nothing
    as yet.
        3. the energy associated with the exponential portion of the
    universe's expansion, the one that has to do with Einstein's "blunder"
    that proved to be more right than wrong.

    These three things encompass all we know to exist of have effect in the
    universe. Even though we do not know the nature of two of these, there
    is clear evidence of their reality.

    The surprising result is that when these three entities are summed, they
    add up to 1 ± 0.02.

    This is a remarkable result for there is no analytical reason why this
    should be. The individual numbers could have turned out to be anything,
    but in reality they somehow are similar in magnitude, and somehow do add
    up to unity. They don't sum to decimal fraction, not 2, nor 10^6, but
    simple beautiful unity, the smallest positive integer, and the smallest
    prime, a number which uniquely divides itself and multiplies itself to
    produce itself as the result. Moreover, Dr. Windhorst said, if the
    value deviated from 1 even slightly, or even if the value varied
    slightly from 1 near the beginning, or today, or any time between, the
    universe would not be as we know it now.

    Given that, I would think this sort of astonishing "coincidence" would
    speak strongly to one with your perspectives.
    The "problem" is that it flows directly out of the data and computations
    that yield the 13.7 billion year age of the universe.

    Should this surprising result be viewed as an internal authentication of
    the validity of the earth age?
    Why not?
    Should I view this is possible legerdemain?

    JimA
Received on Mon Apr 18 09:09:40 2005