The Solar System May Have Two New Members

By Joelle Renstrom | Updated

This article is more than 2 years old

EightTNOsIf you’re still crying about the demotion of Pluto, it’s probably time to focus on something else, namely, on the possibility that the dwarf planet isn’t the end of our solar system. Scientists have recently uncovered new evidence suggesting that the elusive “Planet X” might be real, and there might be two of them.

The idea of Planet X goes back more than 150 years. By then, astronomers knew about Uranus, but they also discovered that its orbit was wonky, which made them suspect Uranus was under the gravitational influence of another planet. In 1846, Neptune was discovered, but astronomers noted that Neptune’s orbit was also a bit odd. Hence, Pluto—except not really. As it turns out, Pluto is too small to have the kind of effect on Neptune astronomers noticed. So they figured there could be yet another planet, a bigger one, out past Neptune.

The Voyager 2 spacecraft cast doubt on those theories when it gathered information showing that Neptune isn’t as massive as scientists thought, and when its orbit is recalculated with the new information, it’s not strange at all (nor is the orbit of Uranus). And neither Voyager spacecraft observed any gravitational force exerted by some other planet. There have been a couple dwarf planets identified out in that region, though: Senda and 2012 VP113. It’s unclear how exactly they got that far away from the sun. Perhaps they formed closer in and then moved, perhaps tugged by one of those bigger planets that could be lurking out past Neptune. But then how did that planet get to be there?

orbitsExaminations of the orbits of Sedna and 2012 VP113 reveal something interesting. Their orbits intersect at the point closest to the sun, which also happens to be near the orbital range of all known planets in the solar system.

Coincidence? They think not. A couple of astronomers from Madrid recently published an article in the Monthly Notices of the Royal Astronomical Society Letters arguing that it’s likely that not one, but two “trans-Plutonian planets must exist.” They also believe like these planets (and/or Planet X, if it exists) are way farther from the sun than originally suggested. The mass would determine that distance—they argue that a planet twice the mass of Earth would have to be at least 500 AU (astronomical units—one AU is equivalent to ~93 million miles) from the sun.

Some scientists still think this notion is farfetched, and that perhaps Neptune’s gravity is what has this effect on all of the planets, but that doesn’t explain the orbits of Sedna and 2012 VIP113. In the meantime, scientists will step up their search for planets, dwarf planets, and other objects that might lend insight into these observations. And certainly, conspiracy theorists will likely interpret such findings as evidence that indeed, the government is hiding Planet X (sometimes called Nibiru) and its many secrets.