Tutorial. News of the Universe
Cosmic Ripples Seen by Galaxy Surveys
11 Jan 2005 - Both the Sloan Digital Sky Survey and the 2 Degree Field Galaxy Redshift Survey reported the discovery of features in the distribution of nearby galaxies that correspond to the oscillations seen in the anisotropy of the Cosmic Microwave Background for several years. The overall statistical significance of this result is good but not great: 3.5 standard deviations. But observations of these ripples provide two valuable new constraints on cosmological models, and verify the current Lambda-CDM model of the Universe. The detection of these ripples is shown at right in a version of Figure 3 from a technical paper describing these results. It gives a matter density in gm/cc that agrees with the value found by WMAP. Both WMAP and the SDSS measure this density to a precison of 8% and their values agree to within 5%. Combining the CMB and SDSS data gives an improved limit on the total density of the Universe: Omegatot = 1.01 +/- 0.009. If Omegatot = 1, the Universe is flat; if Omegatot > 1 the Universe is closed; while if Omegatot < 1 the Universe is open.
NOTES:
Look at that Omega! This latest result is the same as Maxima, Boomerang and WMAP.
Ned wisely lets the reader draw his or her own conclusions. Space, though observationally flat is in fact, closed. This relates to duality, inverse mapping- and a quasi-static universe.
Hawking in his remarks refers to "the saddle",
however I'm sure Dr Hawking knows what that Omega of 1.01 infers about the structure of the universe!
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