Newton

Our solar system officially houses eight planets, but some scientists say there could be a ninth hiding on the fringes. Now, a new study has found the oddities could be explained by modified theories of gravity, an alternative idea to dark matter.

Astrophysicists have observed puzzling behavior in star clusters that defies our current understanding of gravity at cosmic scales. Intriguingly, the observations fit with an alternative theory of gravity that could negate the need for dark matter.

Researchers with the Lawrence Berkeley National Laboratory and the University of California Berkeley have measured what is believed to be the smallest force yet recorded – 42 yoctonewtons, or a septillionth of a newton.