More support for the big bang

Two questions confront those who would interpret recent measurements of the far‐infrared background radiation in the night sky. The first is: Are the data compatible with what would be expected from a blackbody cosmic background, left over from a “big‐bang” origin of the universe? And if so, what is the equivalent temperature of the blackbody? The second problem is: What is going on down at much shorter wavelengths—around 100 microns—where the blackbody envelope has fallen essentially to zero, but radiation has been detected with an apparent diurnal variation? Late last year two groups, one at the Los Alamos Scientific Laboratory, the other at the Naval Research Laboratory in Washington D.C., reported new far‐infrared measurements. The Los Alamos work at millimeter wavelengths supports “big‐bang” cosmology with a 3.1‐K equivalent blackbody temperature, and the new 100‐micron data from both groups suggest that discrepancies already noted in earlier work may besigns of real variation in the flux.