Elusive Planet Nine Could Be Evidence That Gravity Doesn't Work Like We Initially Thought

The elusive and hypothetical Planet Nine may not actually be a planet. A new study suggests that it could be an alternative form of gravity.

Planet Nine A Form Of Gravity Not A Planet?

According to a recent study, the mysterious Planet Nine, which is thought to be hiding somewhere in the solar system's outer reaches, might not actually be a planet after all. Instead, what we perceived to be a huge object might actually be proof that gravity isn't as solid as we thought it is. Planet Nine could be an alternative form of gravity masquerading as a planet.

The Planet Nine hypothesis initially put up in 2016, contends that the existence of an undiscovered ninth planet up to 10 times as big as Earth can explain the strange orbits of objects in the Kuiper Belt beyond Neptune, which appear to be being dragged away from the sun. Since then, astronomers have been searching for Planet Nine. But so far, they have found nothing despite scouring nearly half of the night sky.

According to the latest study, there aren't any gravitational anomalies to be found in the outer solar system. Instead, the team demonstrates that the contradictions are totally eliminated when modified Newtonian dynamics (MOND), a different theory of gravity, is used.

According to Isaac Newton's second law, an object's gravitational pull is inversely proportional to the distance between it and the object pulling it, implying that gravity becomes weaker as the two objects' separation grows. However, MOND modifies this and proposes that the gravitational attraction, beyond a certain distance, is directly proportional to the distance, i.e., the gravitational pull intensity does not decrease as quickly at longer distances. This implies that anything orbiting a more massive object at a considerable distance, such as stars on the periphery of spiral galaxies like the Milky Way, would feel a stronger gravitational force than the second law would imply.

The remainder of our galaxy, rather than an undiscovered planet, is pulling on Kuiper Belt objects, according to MOND. Their findings startled the researchers, who initially wanted to "rule out" MOND as a potential explanation for Planet Nine using their research. But when they used it to remedy the issue, it looked to work wonderfully.

"MOND is really good at explaining galactic-scale observations," study author Harsh Mathur, a theoretical physicist at Case Western Reserve University in Ohio, said in a statement. "But I hadn't expected that it would have noticeable effects on the outer solar system."

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What Is Planet Nine?

Planet Nine is a hypothetical world and, if found, will be a newfound planet to be recognized within the solar system. Astronomers have been searching for it for decades but found none.

Astronomers thought Planet Nine might exist in the early 1900s because it would explain the "wobbles" in Uranus and Neptune's orbits. When Pluto was discovered in 1930, astronomers assumed this was the 'ghost planet' they had been looking for, and the hunt was done. It was believed that another planetary body's gravitational pull was to blame.

However, the search was revived when it was discovered that Pluto was too small to have an impact on Neptune and Uranus. Pluto was eventually downgraded to a dwarf planet.

NASA declared that the orbits of the outer planets were completely normal and had no anomalies based on information gathered from Voyager 2's fly-by of Neptune in 1989. So, it appeared at this point that they had been looking for something that didn't exist.