September 10, 2016

"One team of cosmologists has used the oldest radiation there is, the afterglow of the big bang, or the cosmic microwave background (CMB), to show that the universe is 'isotropic,' or the same no matter which way you look: There is no spin axis or any other special direction in space."

Science: In fact, they estimate that there is only a one-in-121,000 chance of a preferred direction—the best evidence yet for an isotropic universe. by Adrian Cho

'That finding should provide some comfort for cosmologists, whose standard model of the evolution of the universe rests on an assumption of such uniformity.

'"It's a much more comprehensive analysis than in previous cases," says Anthony Challinor, a cosmologist at the University of Cambridge in the United Kingdom who was not involved in the work. "The question of how isotropic is the universe is of fundamental importance."

'"For the first time, we really exclude anisotropy," [Daniela] Saadeh says. "Before, it was only that it hadn't been probed."

'But just how significant is that advance? That's hard to judge, Challinor says, because there aren't compelling alternatives to the standard model of cosmology that predict exactly how an anisotropic universe should be. "The problem is, what do you compare it to?" he asks. Still, he notes, "this assumption is fundamental cosmology" so "it's very important to check."'

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