Monday, November 3, 2008

DARK ENERGY – A NEW LAW OF PHYSICS? (II)

In the previous article I stated that the dark energy - vacuum equation of state:

w = (p / rho) = -1

is consistent with Einstein's general theory of relativity - which one could say approaches the status of a 'basic law of physics'.

I now want to delve into more detail. Take the equation that defines cosmic expansion:

R’’/R = - 4pi/ 3 G rho (1 + 3 w)

And if we let w = (-1/3):

the whole right side becomes zero, and

-1/3 = p/rho or -rho = 3p

If we set: 0 = (rho + 3p) then:

p = - rho /3

and if: p < (- rho /3) we have gravity that repels

Looking back to the earlier equation for w, one finds:

p = - rho (e.g. pressure = - energy density)

and - rho < (- p /3)

Specifically the term (rho + 3 p) acts as a source of gravity in general relativity, (where rho = energy density).

In this case, a negative pressure dovetails with general relativity's allowance for a "repulsive gravity" - since any negative pressure has associated with it gravity that repels rather than attracts.

This being the case, we may assert that dark energy represents no "new law" of physics, but rather an extrapolation of an existing one. The core issue that still must be addressed is whether this relationship implies the need for a "cosmological constant" and if so, what magnitude it might be.

This brings us to the question: What’s to become of the cosmos if the acceleration is ongoing?

All this in tandem supports the prediction by many dark energy theorists that the cosmos will ultimately expand forever and yield to an ultimate heat death. All objects in the cosmos will be so far apart that no exchange of energy can occur and they will simply die out. Or, exhaust all heat sources and become cold, dead cinders. There simply isn't any agency to counter the accelerating force of dark energy to prevent it.

Will the discovery of the Higgs particle (boson) by the large hadron collider cause us to reassess this end? Not really! Not unless there is some corelative data that also show there is no basis to posit an accelerating expansion.

In the absence of that, the best tack to try to overturn the dark energy thesis is to try to find an alternative explanation for the two close peaks in the power spectrum - indicating that the plasma is subject to the dark energy equation of state. Thus, the current primacy of the dark energy thesis rests on a particular interpretation for those two power spectrum peaks based on using the Legendre functions.

If anyone has any evidence to the contrary, and can PROVE it (using the same power spectrum and the Legendre functions) points to a collapsing universe instead, then go for it.