A recent study has discovered evidence that challenges our current understanding of gravity. The study focused on the orbital motions of widely separated binary stars, known as “wide binaries,” and found that at low accelerations, the standard model of gravity breaks down.
Researchers analyzed data from 26,500 wide binaries and found that accelerations below one nanometer per second squared deviated from Newton’s and Einstein’s gravitational laws. This finding aligns with a modified theory called Modified Newtonian Dynamics (MOND) and challenges current concepts of dark matter.
The study, led by Kyu-Hyun Chae, a professor of physics and astronomy at Sejong University in Seoul, used the European Space Agency’s Gaia space telescope to observe up to 26,500 wide binaries within a distance of 650 light years. Chae’s study focused on calculating the gravitational accelerations experienced by binary stars as a function of their separation or orbital period.
The study revealed that when two stars orbit each other with accelerations lower than about one nanometer per second squared, they deviate from the predictions of Newton’s universal law of gravitation and Einstein’s general relativity. For accelerations below approximately 0.1 nanometer per second squared, the observed acceleration was about 30 to 40 percent higher than predicted. These deviations meet the conventional criteria of 5 sigma for a scientific discovery.
Interestingly, the breakdown of Newton-Einstein theory at weaker accelerations was suggested 40 years ago by theoretical physicist Mordehai Milgrom. Milgrom’s theory, known as MOND or Milgromian dynamics, predicted the boost in accelerations observed in the study.
Chae’s results have significant implications for astrophysics, theoretical physics, and cosmology. Unlike galactic rotation curves, where the observed boosted accelerations can be attributed to dark matter, wide binary dynamics cannot be affected by dark matter even if it exists. This suggests that the standard gravity breaks down in the weak acceleration limit in accordance with the MOND framework.
The findings challenge current concepts of dark matter and dark energy and could revolutionize our understanding of gravity. If confirmed through further independent analyses, this discovery will have enormous implications for astrophysics, cosmology, and fundamental physics.
Experts in the field have acknowledged the significance of this discovery. Xavier Hernandez, a professor at UNAM in Mexico, who first suggested wide binary tests of gravity, expressed excitement over the confirmation of the departure from Newtonian gravity and the accurate identification of the deviation corresponding to the MOND model.
Pavel Kroupa, a professor at Bonn University and Charles University in Prague, also came to the same conclusions concerning the law of gravitation. He emphasized the immense implications of these findings for astrophysics as a whole.
While the results are promising, further confirmation by independent analyses and better future data is required to solidify these findings.
The study was published in the 1 August 2023 issue of The Astrophysical Journal, and its implications are expected to generate significant discussions and advancements in the field of physics.