Exploring the “cosmic imbalance” in gravity

We're one step closer to understanding the mysteries at the edge of the universe.

A group of researchers in University of Waterloo The University of British Columbia discovered a possible “cosmic imbalance” in the universe's gravity, which explains its strange behavior at the cosmic level.

For the past 100 years, physicists have relied on Albert Einstein's theory of “general relativity” to explain how gravity works throughout the universe. General relativity, proven accurate by countless tests and observations, indicates that gravity affects not only three physical dimensions, but also a fourth dimension: time.

“This model of gravity has been essential for everything from endoscopy the great explosion Robin Wynn, the project's lead author, a recent graduate in mathematical physics at Waterloo, said:

Challenges on a global scale

“But when we try to understand gravity at the cosmic level, at the level of galaxy clusters and beyond, we encounter clear contradictions with the predictions of general relativity. It is as if gravity itself has completely stopped matching Einstein's theory. We call this contradiction a 'cosmological glitch'.” “Gravity becomes about 1% weaker when dealing with distances of billions of light years.”

For more than twenty years, physicists and astronomers have been trying to create a mathematical model that explains apparent contradictions in the theory of general relativity. Many of these efforts have been undertaken at Waterloo, which has a long history of cutting-edge gravitational research resulting from ongoing interdisciplinary collaboration between applied mathematicians and astrophysicists.

Historical context and research efforts

“Almost a century ago, astronomers discovered that our universe is expanding,” said Niayesh Afshordi, a professor of astrophysics at the University of Waterloo and a researcher at the Perimeter Institute.

“The farther away the galaxies are, the faster they move, to the point where they appear to be moving at almost the speed of light, the maximum allowed by Einstein's theory. Our findings suggest that Einstein's theory, on these same scales, may also be inadequate.”

Modifying Einstein's theory

The research team's new model of a “cosmological glitch” modifies and extends Einstein's mathematical formulas in a way that resolves the inconsistency of some cosmological measurements without affecting existing successful uses of general relativity.

“Think of it as a footnote to Einstein’s theory,” Wen said. “Once you reach the Cosmic Realm, terms and conditions apply.”

“This new model may be just the first piece of evidence in the cosmic puzzle that we are beginning to unravel across space and time,” Afshordi said.

The study, titled “A Universal Gravity Flaw,” appears in Journal of Cosmology and Astroparticle Physics.

Reference: “Cosmic Gravity Glitch” by Robin Y. Wen, Lucas T. Herget, Niayesh Afshordi, and Douglas Scott, March 20, 2024, Journal of Cosmology and Astroparticle Physics.
doi: 10.1088/1475-7516/2024/03/045