Fig13_1 CMB spectrum

Fig13_1 CMB spectrum

Fig. 13.1 . The intensity of the cosmic microwave background radiation plotted as a function of wavelength. This thermal radiation was formed about 390,000 years after the big bang, which occurred about 13.7 billion years ago. The observed radiation has a nearly perfect blackbody spectrum. Pioneering measurements by Arno A. Penzias (1933? ) and Robert W. Wilson (1936? ) in 1965 and Peter G. Roll (1935? ) and David T. Wilkinson (1935?2002) in 1966, at 7.35 cm and 3.0 cm wavelength respectively, are compared to the expected spectrum of a three-degree blackbody and radiation from our Galaxy (bottom). The full spectrum at millimeter wavelengths (top) was obtained from instruments aboard the COsmic Background Explorer, abbreviated COBE, in late 1989. This data is so accurate that the error bars of the individual points all lie within the width of the plot curve. This solid line, which matches the shape and peak location of the observed data, corresponds to a thermal radiator, or blackbody, with a temperature of 2.725 K.

Copyright 2010, Professor Kenneth R. Lang, Tufts University