According to NBC News, new research might disprove the long-held theory of dark matter. A team of scientists reported a unique gravitational effect across distant stars that suggests our understanding of gravity is incomplete. In time, when our understanding of gravity is more comprehensive, clouds of dark matter thought to hold galaxies together might give way to new mathematical equations.

Still, the dark matter theory is not completely disproven, and there are some theories as to what the mysterious substance could be, such as neutrinos or primordial black holes. But a rival theory developed in the 1980s called the modified Newtonian dynamics theory, or MOND, has gained credence by the recent findings. The theory suggests that Isaac Newton’s original theories concerning gravity were not entirely accurate, which would explain the discrepancies without including dark matter. Though dark matter is still the more popular hypothesis, and MOND is far from foolproof, the tides of science might be changing.