Space & Astronomy

Alternative theory of gravity could explain evidence of Planet Nine

By T.K. Randall
October 16, 2023 ·  7 comments

Perhaps Planet Nine really isn't there at all... Image Credit: NASA / Caltech/R. Hurt (IPAC) Nobody knows exactly where it is, how big it is or if it even exists at all, but when researchers at the California Institute of Technology revealed in 2016 that the existence of a ninth planet in our solar system was a very real possibility, the hunt for this enigmatic new world began in earnest.

Believed to be up to ten times the mass of the Earth and with an orbital period of up to 20,000 years, Planet Nine, if it exists, will be situated somewhere beyond the orbit of Neptune.

As things stand, however, it is looking increasingly unlikely that it is actually out there at all.Now a new study has cast even further doubt on the possible existence of this mysterious planet by theorizing that the gravitational anomalies indicative of the planet's presence might simply be due to the way gravity behaves under what is known as modified Newtonian dynamics (MOND).

The precise physics involved are complex, but to put it simply - it suggests that the observed gravitational pull on objects in the outer Kuiper Belt may actually be due to the pull of the rest of the Milky Way galaxy than due to the pull of a large, undiscovered planet.

"Regardless of the outcome, this work highlights the potential for the outer solar system to serve as a laboratory for testing gravity and studying fundamental problems of physics," said theoretical physicist and study author Katherine Brown of Hamilton College, New York.

Source: Live Science | Comments (7)

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