The existence of dark matter has been considered a 'given' for decades as a way to understand some of the less explainable aspects of gravitational behavior in space. Now, an international team of scientists has published research suggesting that dark matter may not need to exist after all.
The problem arose when scientists found that there wasn't enough visible or known matter to account for the observed gravitational pull in space. As such, some suggested that the main component of the universe- making up 75% of its matter- is undetectable as it doesn't interact with light. Coined 'dark matter', it has since been the prevailing theory for almost 50 years, even though it has never been observed.
Another theory was also proposed, however, to explain this problem in the early 1980's. Known as Milgroian dynamics (MOND) theory, it instead says that this gravitational pull exists due to slightly altered rules of gravity. The theory contends that gravity is stronger at low accelerations than is predictable with a pure Newtonian understanding.
The theory further states that the internal motion of objects in the cosmos should depend on the gravitation pull from all other masses in the universe as well as their own. This is known as an 'external field effect' (EFE) and, if confirmed, would prove the dark matter theory obsolete.
In the present study, researchers say that they were able to detect EFE in 153 galaxies. Working under the hypothesis that dark matter exists, they were surprised that their findings supported the alternative MOND theory, even after months of verifying their data.
"I came from the same place as those in dark matter community," says Stacy McGaugh, one of the authors of the study. "It hurts to think that we could be so wrong. But Milgrom predicted this over 30 years ago with MOND. No other theory anticipated the observed behavior."