Does the universe have a total angular momentum?

Asked by: B.Gibson

Answer

The answer is no: or at least, the total angular momentum of the universe is zero. The equations that describe our universe are predicated on the assumption that the universe is isotropic. That means there is no preferred direction in space. If there was a total angular momentum for our universe then since this is a vector quantity it would represent a preferred direction. The fact that these equations accurately reflect the universe we observe on its largest scale suggests that no such preferred direction exists.

Of course our universe isn't precisely isotropic. There are very, very small variations in the cosmic microwave background radiation for example, but on the scale of the overall universe these sorts of things are enough to produce an appreciable angular momentum.
Answered by: Brent Nelson, M.A. Physics, Ph.D. Student, UC Berkeley