Radio-astronomy array images distant Universe and finds . . . laser speckle?

(Credit: Condon et al., NRAO/AUI/NSF) The image required staring at a small patch of sky for 50 hours with the VLA; for the first time, discrete sources were identified that account for nearly all the radio waves coming from distant galaxies. About 63% of the background radio emission comes from galaxies with active black holes at their cores and the remaining 37% comes from galaxies that are rapidly forming stars. The field of view, in the constellation Draco, encompasses about one-millionth of the whole sky. In that region, the NRAO astronomers identified about 2000 discrete radio-emitting objects. That would indicate, the scientists say, that there are about 2 billion such objects in the whole sky. These are the objects that account for 96% of the background radio emission. However, the researchers point out, the remaining 4% of the radio emission could be coming from as many as 100 billion very faint objects. Who knows -- maybe the same people who believe the Apollo moon landings were actually filmed in a Hollywood studio will fall for the idea that this spectacular image was actually the result of a He-Ne laser beam sent through a diffuser. However, I suspect that the intersection of the two following sets: 1) moon-landing conspiracists, and 2) people who know what laser speckle is, will amount to approximately zero. Source: http://www.nrao.edu/pr/2013/vladeep/

John Wallace | Senior Technical Editor (1998-2022)
John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.