Re: Question for Cosmologists

It is not obvious that the present acceleration due to dark energy & that which is supposed to have produced inflation in the early universe are the same qualitative phenomenon. & it also isn't obvious that solutions to all cosmological problems are to be sought at the quantum level. The involvement of particle physicists with cosmology during the last 50 years has been healthy in many ways, but it's caused people to lose sight of the fact that some of the answers need to be sought in global phenomena. The fact that we don't know what ~95% of the universe is ought to give a certain degree of humility, as should the fact that the cosmological term turned out to be a step in the right direction in spite of all the derision directed to it as a "fudge factor," "my greatest blunder" &c.

Shalom
George
http://web.raex.com/~gmurphy/
  ----- Original Message -----
  From: Rich Blinne
  To: George Murphy
  Cc: Pim van Meurs ; asa
  Sent: Friday, January 13, 2006 12:22 PM
  Subject: Re: Question for Cosmologists

  You guys seem to have a good handle on this. Please help uncloud my thinking because I don't seem to get it.

  For the cosmological constant w0 is -1 and w' is 0. What is being proposed is w0 = -1.3 and w' = 1.55. Maybe I am making a sign error here but it seems that inflation decreases as you go back in time. Don't you need the highest inflation at highest z for fine-tuning to be solved? I grant George's point about extrapolating from z = 6.3. Details can be found here.

  Confusedly Yours,
  Rich

   
  On 1/13/06, George Murphy <gmurphy@raex.com> wrote:
    1) I don't think many cosmologists will be surprised if it turns out that
    Einstein's form of "dark energy" (which of course isn't what he called it)
    is only a limited approximation.

    2) It's unlikely that present observations on dark energy can be
    extrapolated in any reliable way back to the first fractions of a second
    wiith which inflation (in the original sense of the term) was significant.

    Shalom
    George
    http://web.raex.com/~gmurphy/
    ----- Original Message -----
    From: "Pim van Meurs" <pimvanmeurs@yahoo.com >
    To: "Rich Blinne" <rich.blinne@gmail.com>
    Cc: "asa" <asa@calvin.edu>
    Sent: Friday, January 13, 2006 12:07 AM
    Subject: Re: Question for Cosmologists

> Rich Blinne wrote:
>
>> Note the following story in New Scientist
>> < http://www.newscientistspace.com/article.ns?id=dn8566&feedId=online-news_rss20>:
>>
>> Dark energy – the mysterious force that drives the acceleration of the
>> universe – changes over time, controversial new calculations suggest. If
>> true, the work rules out Einstein's notion of a "cosmological constant"
>> and suggests dark energy, which now repels space, once drew it together.
>> [emphasis mine]
>>
>> My question for the cosmologists on this group is as follows: Does this
>> not imply that inflation is incorrect and by extension so is the
>> multiverse explanation of fine-tuning?
>
> The study shows that Einstein's cosmological constant has been disproven
> with 97% probability if independent methods support this finding. Which
> means that the acceleration in the young universe was less than expected.
>
> The quickening of the universe's expansion is affected by dark matter, and
> the study suggests that dark matter has changed over time, conflicting
> with a constant cosmological constant.
> I do not believe the inflationary theory depends on this, and inflationary
> theory has been verified by the cosmic background radiation.
>
> But the study has its issues
> http://www.nytimes.com/2006/01/12/science/12cosmos.html
>
> Moreover, he said, if Dr. Schaefer's analysis is valid, his results agree
> with Einstein's constant, within the measurements' uncertainties.
>
> "It's not a meaningful discrepancy," Dr. Lamb said, adding that a
> statement like Dr. Schaefer's required stronger evidence. "The bottom line
> is the result doesn't show Einstein was right. And it doesn't show he was
> wrong."
>
>
>
>
Received on Fri Jan 13 16:34:03 2006