Almost everything in the universe rotates. Planets rotate on their axis, stars rotate around black holes, and galaxies rotate in large spiral structures. But what about the universe as a whole? Could it be spinning too?
Structures rotate due to a property known as angular momentum. Angular moment is a measure of mass and rotation. One of its characteristics is that when the mass approaches, it rotates faster to keep the angular momentum constant. Galaxies, stars, and planets were formed from large clouds of cosmic gas and dust. As gravity caused these clouds to collapse, even the smallest twist was amplified, making it natural for all of them to turn.
But what happens on a cosmic scale? Things are different. The universe is generally believed to be homogeneous and isotropic. This means that, on average, matter must spread out uniformly and that the total angular momentum of the cosmos must be approximately zero. If that’s true, the rotation of the galaxies should be random. If we look, therefore, at any region of space, about half should be rotating clockwise, and half counterclockwise.
However, there is some scientific evidence that the galactic rotation is not homogeneous . In 2011, a study of 15,000 galaxies found that there was a small bias in this rotation. Due to the relatively small sample size, the evidence was weak, but the study just presented at the 236th meeting of the American Astronomical Society has shown a much stronger bias.
The early universe may have been spinning
Researchers at Kansas State University (USA) used three of the most powerful observatories in the world: the Sloan Digital Sky Survey, the Panoramic Survey Telescope and Rapid Response System and the Hubble Space Telescope, to find the direction of rotation of more than 200,000 spiral galaxies across the sky. They used artificial intelligence to classify those hundreds of millions of spiral galaxies and understand how they rotated.
Based on the above data without taking into account the small bias, we would expect that there would be an equal number of galaxies rotating clockwise and counterclockwise. But when they looked at the data from each of the three observatories, they found an unexpected imbalance :
“The difference is not huge, just over 2%, but with such a large number of galaxies, the probability of having such a division by chance is less than one in a million,” said Lior Shamir, leader of the work. The farther away the galaxies are, the greater the imbalance.
The asymmetry is also different depending on where in the sky you look at it. Looking outward from near Earth’s poles, more galaxies appeared to rotate counterclockwise than clockwise, while the reverse was true for observations near the equator.
“Since the spin patterns of a galaxy visible from Earth are also an indication of the galaxy’s actual spin direction, large-scale patterns in the spin directions distribution can be an indication of a spinning universe. ” , clarifies Shamir.
If the universe is isotropic, or uniform in all directions, as described by the cosmological principle, there should be a fairly uniform 50-50 distribution of galaxies clockwise and counterclockwise everywhere; But the split the recent study identifies was closer to 51-49 , with more galaxies going clockwise than counterclockwise.
That doesn’t mean that the universe itself is spinning around a single point like a giant spiral galaxy. Rather, there is evidence that it rotated through multiple complex and changing axes at once.
The researchers claimed that these conclusions would not be the result of an error, but instead showed us the unusual structure of the universe around us.
“There is no error or contamination that can be exhibited through such unique, complex and consistent patterns,” said Shamir. “We have two different sky surveys that show exactly the same patterns, even when the galaxies are completely different. There is no mistake that can lead to that. This is the universe we live in. This is our home. “
Referencia: Kansas State University. “Asymmetry found in spin directions of galaxies: Research also suggests the early universe could have been spinning.” ScienceDaily. ScienceDaily, 1 June 2020. Multipole alignment in the large-scale distribution of spin direction of spiral galaxies Lior Shamir https://arxiv.org/abs/2004.02963
