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SUMMARY:Dark energy without dark energy - David L Wiltshire (Canterbury U.
 )
DTSTART:20080526T120000Z
DTEND:20080526T130000Z
UID:TALK11402@talks.cam.ac.uk
CONTACT:David Mulryne
DESCRIPTION:I present an unexpected explanation for dark energy [1]\, pure
 ly within\ngeneral relativity with matter obeying the strong energy condit
 ion.\nCosmic acceleration is explained quantitatively\, as an apparent eff
 ect due\nto quasilocal gravitational energy differences - and hence clock 
 rate\nvariance - that arise in the decoupling of bound systems from the gl
 obal\nexpansion of the universe. Although the universe was initially very 
 smooth\,\ntoday it is very inhomogeneous on scales less than 200 Mpc\, wit
 h clusters\nof galaxies strung in filaments and bubbles surrounding huge v
 oids.\nAccounting for spatial curvature and gravitational energy gradients
 \nbetween galaxies and the volume average location in voids\, leads to a\n
 recalibration of average cosmological parameters.\n\nI present a model [1\
 ,2] of the universe based on this proposal\, which\npasses three key indep
 endent cosmological tests [3]: supernova luminosity\ndistances\, the angul
 ar scale of the sound horizon in the cosmic microwave\nbackground (CMB) an
 d the baryon acoustic oscillation scale in galaxy\nclustering statistics. 
 It may simultaneously resolve particular\nanomalies\, including primordial
  lithium abundances and CMB ellipticity.\nThe expansion age is increased a
 llowing more time for structure formation.\nBest-fit parameters and implic
 ations will be discussed. Unique predictions\ninclude a quantifiable varia
 nce in the Hubble flow below the scale of\napparent homogeneity\, consiste
 nt with the observed "Hubble bubble"\nfeature\, which sheds new light on t
 he decades long debate about the\nvalue of the Hubble constant.\n\n[1] D.L
 . Wiltshire\, New J. Phys. 9 (2007) 377\n[2] D.L. Wiltshire\, Phys. Rev. L
 ett. 99 (2007) 251101\n[3] B.M. Leith\, S.C.C. Ng and D.L. Wiltshire\, ApJ
  672 (2008) L91\n
LOCATION:Potter Room\,  CMS\, Pav.B\, First Floor Common Room (B1.19)
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