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diff --git a/ClassJuly20.page b/ClassJuly20.page index e667e8d..9c1ffef 100644 --- a/ClassJuly20.page +++ b/ClassJuly20.page @@ -10,7 +10,7 @@ Somewhat related to the contents of this lecture and our discussions afterwards,  -One of the most important metrics calculated from CMB (cosmic microwave background) skymaps (like those from WMAP, or this [super pretty new map](http://4.bp.blogspot.com/_GVA115I1I8Y/TDLWxv-FiDI/AAAAAAAAAww/P_cC-oE67uQ/s1600/PLANCK_FSM_03_Black.jpg) from Plank) is the power spectrum: This is essentially the Fourier transform of the surface of the sphere using spherical harmonics (indexed by $\el$ instead of $n$; familiar from physical chemistry and the quantum mechanics of the hydrogen atom). The power spectrum of the skymap, which basically describes the relative populations of lumps in the skymap, is the established meeting ground between early universe theorists (who calculate what the power spectrum would look like under different cosmological models, such as inflationary, open/closed/flat, cosmic strings, quantum loop gravity, cold-dark-matter-dominated, and other pseudo-nonsense wink-wink) and observational scientists who try to constrain the spectrum with better and better measurements. +One of the most important metrics calculated from CMB (cosmic microwave background) skymaps (like those from WMAP, or this [super pretty new map](http://4.bp.blogspot.com/_GVA115I1I8Y/TDLWxv-FiDI/AAAAAAAAAww/P_cC-oE67uQ/s1600/PLANCK_FSM_03_Black.jpg) from Plank) is the power spectrum: This is essentially the Fourier transform of the surface of the sphere using spherical harmonics (indexed by $\ell$ instead of $n$; familiar from physical chemistry and the quantum mechanics of the hydrogen atom). The power spectrum of the skymap, which basically describes the relative populations of lumps in the skymap, is the established meeting ground between early universe theorists (who calculate what the power spectrum would look like under different cosmological models, such as inflationary, open/closed/flat, cosmic strings, quantum loop gravity, cold-dark-matter-dominated, and other pseudo-nonsense wink-wink) and observational scientists who try to constrain the spectrum with better and better measurements.  |