A scientist has observed a “gravitational anomaly” in certain star systems that could potentially upend a fundamental assumption about the universe, according to a new study.
The anomaly arises when loosely orbiting stars, known as wide binaries, seem to move in ways that defy established models of gravity, which are based on the ideas of Isaac Newton and Albert Einstein. The mind-bending discovery hints at a possible alternate theory of physics that does not depend on the existence of weird unidentified phenomena, such as dark matter, to explain the phenomena we see in space.
Kyu-Hyun Chae, an astronomer at Sejong University, has now put these models to the test by analyzing the accelerations of stars in 26,500 wide binaries located within about 650 light years of Earth using imagery captured by the European Space Agency’s Gaia observatory. Scientists have previously searched for signs of modified gravity in these systems, but Chae took the next step by developing a new code that could account for special details, like the occurrence rate of so-called “nested” binaries in which the loosely orbiting stars also have close stellar companions.
The new data suggests that when the gravitational accelerations of these stars slip below one nanometer per second squared, they begin to move in ways that are more aligned with MOND models than by the standard model. Chae said the findings offer “direct evidence for the breakdown of standard gravity at weak acceleration” and reveal “an immovable anomaly of gravity in favor of MOND-based modified gravity,” according to a recent study published in The Astrophysical Journal.
“When the results started to show up from my new and more reliable code, my initial reaction was that it was unbelievable,” Chae said in an email to Motherboard. “I was feeling like I was dreaming. It seemed so unreal. This is because my results did not match any previous results.”
“Several previous results even claimed that the standard gravity was preferred by wide binaries data including Gaia DR3,” he continued. “One group has been claiming an anomaly for some time, but the anomaly seemed not to match well the predictions of existing modified gravity theories. However, those previous studies did not self-calibrate or fully take into account the amount of hidden nested binaries.”