tag:blogger.com,1999:blog-3612697638678594412.post6096276675213655223..comments2024-03-26T21:35:39.266-07:00Comments on CANDELS: Exciting News from the Planck SatelliteAnonymoushttp://www.blogger.com/profile/17704873086455232100noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-3612697638678594412.post-81636595512297621772013-03-22T11:26:04.358-07:002013-03-22T11:26:04.358-07:00A few refinements, after hearing a very nice summa...A few refinements, after hearing a very nice summary of the results by Marc Kamionkowski at Johns Hopkins. <br /><br />First, it's probably wrong to say "the universe is expanding more slowly than we thought." Instead I should have said that the expansion rate estimated from the CMB disagrees with the more direct measurements in the nearby universe. One possible solution is that Dark Energy makes the change in the expansion rate different than the simplest model (in technical terms, the equation of state parameter w might be less than the simplest assumption w=-1). If that interpretation were confirmed it would be a profound discovery. <br /><br />Second, I was confused about the lopsidedness. The measurement of lopsidedness is in the "total power" of the fluctuations, rather than in the "mean temperature." In other words, the difference between the troughs and valleys on the right-hand side of the map is slightly bigger than on the left side of the map. So the explanation that our galaxy might be moving faster in one direction than previously thought is not viable. I expect there are theorists hard at work already trying to come up with simple explanations. <br /><br />Third, Marc was very excited about the implications for inflationary models (used to explain the first tiny fraction of a second of the expansion of the universe). The relative power of fluctuations on different scales was set in place as the universe emerged from its "exponential expansion" phase, so by getting this snapshot of the relative power you can (a) get a lot more confidence that inflation really happened, and (b) actually say something about this transition phase.Harry Fergusonhttps://www.blogger.com/profile/02737594514049700386noreply@blogger.com