Void in the Universe May Not Be Real

A giant void in the universe, seemingly over 1 billion light years across, that was discovered by astrophysicists last year may not exist all, according to Kendrick Smith at the University of Cambridge and Dragan Huterer at the University of Michigan, Ann Arbor.

The void, which seemed to contain fewer stars and galaxies than would be expected, was discovered by Lawrence Rudnick and his team at the University of Minnesota in Minneapolis.  While studying a cold spot in the microwave background, Rudnick came to the conclusion that this cold spot coincided with the largest void in the universe ever known. 

A void must always be inferred statistically, as there will always be some stars in front of it and behind it, so it can’t be seen by the naked eye. Smith and Huterer have raised doubts about the statistical inference, arguing that the cold spot and the presumed void have different centres, and that Rudnick’s team counted only galaxies above a certain luminosity, while focusing on the part of the cold spot that had the fewest galaxies. Smith said that if you change the cut-off point for luminosity and the part of the cold spot you concentrate on, statistically, the void disappears.

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