Unveiling the Enigma: Exploring Modified Gravity and the Hunt for Planet Nine

The hunt for a ninth planet in our solar system may instead be revealing evidence of a modified law of gravity known as Modified Newtonian Dynamics (MOND), according to theoretical physicists Harsh Mathur and Katherine Brown. MOND proposes that Newton's law of gravity is valid up to a certain point, after which a different gravitational behavior takes over. The researchers found that MOND predicts the observed clustering of objects in the outer solar system, which had initially motivated the search for a ninth planet. While the current dataset is small and other possibilities remain, this study highlights the potential for the outer solar system to test gravity and study fundamental physics problems.