Source: Physicsworld
The universe was born spinning and continues to do so around a preferred axis – that is the bold conclusion of physicists in the US who have studied the rotation of more than 15,000 galaxies. While most cosmological theories have suggested that – on a large scale – the universe is the same in every direction, these recent findings suggest that the early universe was born spinning about a specific axis. If correct, this also means that the universe does not possess mirror symmetry, but rather has a preferred right or left “handedness”.
Led by Michael Longo from the University of Michigan, the team had set out to test whether mirror symmetry, also referred to as “parity”, was violated on the largest scales. If a particle violates parity, its mirror image would behave differently, and such particles can be described as right- or left-handed. Parity is violated in nuclear beta decays and there is a strong preference in nature for left-handed amino acids, rather than right-handed.
“To my knowledge, no-one had asked the question of whether the universe itself had a preference of say left-handed over right-handed. My idea was to test this by seeing if there was a preferred sense of rotation of spiral galaxies. At that time, I didn’t quite appreciate that, if so, it meant that the entire universe would have a net angular momentum,” explains Longo.