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The fine structure constant is a measure of electromagnetism, one of the four fundamental forces in nature; the others are gravity, weak nuclear force, and strong nuclear force. In an article published in the magazine. Scientific advances, a team of researchers reported that four new light measurements emitted by ULAS J1120 + 0641, a quasar located approximately 12.9 billion light years away, reaffirm previous studies that have measured small variations in this constant.
This artist’s impression shows what ULAS J1120 + 0641 might have looked like, a very distant quasar powered by a black hole with a mass two billion times greater than that of the Sun. Image credit: M. Kornmesser / ESO.
“The fine structure constant is the amount that physicists use as a measure of the strength of the electromagnetic force,” said Professor John Webb, a researcher at the University of New South Wales in Sydney and corresponding author of the paper.
“It’s a dimensionless number and it involves the speed of light, something called Planck’s constant and the charge of electrons, and it’s a ratio of those things.” And it’s the number that physicists use to measure the strength of the electromagnetic force. “
The electromagnetic force keeps the electrons buzzing around a nucleus in each atom of the Universe; without it, all matter would separate. Until recently, it was believed to be an immutable force throughout time and space.
But in the past two decades, Professor Webb and his colleagues have noted anomalies in the fine-structure constant whereby the electromagnetic force measured in a particular direction of the Universe appears very slightly different.
“We found a clue that that number of the fine structure constant was different in certain regions of the Universe,” said Professor Webb.
“Not only as a function of time, but also towards the Universe, which is quite strange if it is correct, but that is what we found.”
In the current study, Professor Webb and his co-authors observed the extremely distant quasar ULAS J1120 + 0641 that allowed them to investigate when the Universe was only a billion years old, which had never been done before.
The team made four measurements of the fine constant along the line of sight of this quasar.
Individually, the four measurements did not provide any conclusive answer on whether or not there were noticeable changes in electromagnetic force.
However, when combined with many other measurements between us and distant quasars made by other scientists and unrelated to this study, differences in the fine structure constant became apparent.
“And it seems to be supporting this idea that there could be directionality in the Universe, which is very strange,” said Professor Webb.
“So the Universe may not be isotropic in its laws of physics, one that is statistically the same in all directions. But in fact, there could be some preferred direction or direction in the Universe where the laws of physics change, but not in the perpendicular direction. In other words, the Universe, in a sense, has a dipole structure. “
“In a particular direction, we can look back 12 billion light years and measure electromagnetism when the Universe was very young. Putting all the data together, electromagnetism seems to gradually increase the more we look, while in the opposite direction, it gradually decreases. ”
“In other directions in the cosmos, the fine-structure constant remains just that: constant.”
“These very distant new measurements have taken our observations further than ever before.”
In other words, in what was thought to be a random arbitrary distribution of galaxies, quasars, black holes, stars, gas clouds, and planets, with life flourishing in at least a small niche, the universe suddenly seems to have the equivalent of a north and a south.
“While they still want to see more rigorous evidence of ideas that electromagnetism can fluctuate in certain areas of the Universe to give it a form of directionality, if these findings continue to be confirmed, they can help explain why our Universe is the way it is, and why there is life in it, “said Professor Webb.
“For a long time, it has been thought that the laws of nature seem to be perfectly adapted to establish the conditions for life to flourish. The strength of the electromagnetic force is one of those quantities. “
“If it were just a small percentage different from the value we measured on Earth, the chemical evolution of the Universe would be completely different and life could never have started.”
“It raises a tantalizing question: Does this ‘Goldilocks’ situation, where fundamental physical quantities like the fine-structure constant are ‘correct’ to support our existence, apply across the Universe?”
“If there is a directionality in the Universe and electromagnetism is shown to be very slightly different in certain regions of the cosmos, the most fundamental concepts underpinning much of modern physics will need revision.”
“Our standard model of cosmology is based on an isotropic universe, one that is statistically the same in all directions.”
“That standard model itself is based on Einstein’s theory of gravity, which explicitly assumes the constancy of the laws of nature. If such fundamental principles turn out to be only good approximations, the doors are open to some very interesting new ideas. in physics. “
“We believe this is the first step toward a much larger study that explores many directions in the Universe, using data from new instruments in the world’s largest telescopes,” the researchers said.
“New technologies are now emerging to provide higher quality data, and new artificial intelligence analysis methods will help automate measurements and perform them faster and with greater precision.”
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Michael R. Wilczynska et al. 2020. Four direct measurements of the fine structure constant 13 billion years ago. Scientific advances 6 (17): eaay9672; doi: 10.1126 / sciadv.aay9672
