The difference in two values of this quantity produced by Wouthuysen (“vowt-how-sen”)–Field coupling makes it theoretically possible to detect the 21-centimeter line at redshifts greater than six. Vielva et al. detected non-Gaussianity (“non-GOW-see-AAN-it-ee”) in this quantity’s distribution by calculating the skew and kurtosis of spherical Mexican hat wavelet coefficients. After electron-positron annihilation, the ratio of this quantity for neutrinos to this quantity for photons equals the cube root of four-elevenths. WMAP (“W-map”) discovered a region where this quantity is abnormally low, which might be explained by a supervoid. The horizon problem asks why the CMB’s value for this quantity is uniform. The wavelength of a star’s emissions is related to this quantity for a star by Wien's (“veen’s”) displacement law. For 10 points, spectral class and what other quantity are plotted against luminosity on HR diagrams? ■END■
ANSWER: temperature [accept absolute temperature; accept stellar temperature; accept (effective) CMB temperature or CMB temperature anisotropies/fluctuations or CMB temperature distribution; accept HI (“H-one”) excitation temperature or HI (“H-one”) spin temperature; prompt on T; or reject “spin”]
<Other Science>
= Average correct buzz position