Tuesday, February 21, 2006

Dark energy and the future of the universe

I just gave this talk at the UO Center for High Energy Physics (PDF slides). I'm giving it as a colloquium at Washington University in St. Louis and the University of Kansas later in the spring, so no peeking if you are from one of those places.

Title: Dark Energy and the Future of the Universe

Abstract: Recent observations of Type Ia supernovae, cosmic microwave background radiation and large scale structure indicate that the expansion rate of the universe is increasing. A number of models describing exotic forms of matter, generically referred to as dark energy (not to be confused with dark matter), have been proposed to explain this acceleration. For example, the dark energy may be due to Einstein's cosmological constant. In this talk I will give an introduction to big bang cosmology and dark energy, with emphasis on the dark energy equation of state and how it determines the future (large time evolution) of the universe.

1 comment:

Pentcho Valev said...

THE STRANGEST DILEMMA IN PHYSICS

Cosmological concepts like dark energy etc. are all based on frequency shift data and therefore the equations

c = Lf ; c' = L'f'

where c is speed of light, L is wavelength and f is frequency, are crucial. If c'=c=300000km/s we have

c = L'f' /1/

If the speed of light is variable and, as Einstein showed in 1911, obeys the equation c'=c(1+V/c^2), where V is the gravitational potential, /1/ is wrong and we have, instead,

L' = L ; c' = Lf' /2/

Clearly /1/ and /2/ are incompatible and here the strangeness begins. Physicists usually assume that /1/ is true but rarely say /2/ is wrong. Sometimes they give praise to Einstein's 1911 equation c'=c(1+V/c^2) and therefore implicitly assume that /2/ is true and /1/ is wrong. Yet physicists would never openly discuss the implications of /2/: they suspect that this particular discussion has something to do with a prophecy of Einstein's:

"If the speed of light is the least bit affected by the speed of the light source, then my whole theory of relativity and theory of gravity is false."

Pentcho Valev
pvalev@yahoo.com

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