Our solar system has eight known planets, and beyond Neptune’s orbit, one can find small icy bodies such as Pluto. None, however, is already proven to rival our planets in size.
The search for distant worlds and solar systems has made great headways, but debates and uncertainties remain. A case in point: the existence of Planet 9. Now, new observations offer evidence of a planetary mass hiding closer to home, revealing itself by its effects on the space rocks in the Kuiper Belt.
Planet 10: Causing Warp On Kuiper Belt?
The Kuiper Belt shelters minor planets, space rocks, and other objects that orbit the sun with a specific inclination. A new survey by Renu Malhotra and Kat Volk of the University of Arizona’s Lunar and Planetary Laboratory (LPL), however, showed that the most distant objects in the vicinity divert from this particular inclination and are tilted away from the orbital plane by 8 degrees.
What this meant: something big enough could be interfering with such plane and causing the warp on Kuiper Belt.
“According to our calculations, something as massive as Mars would be needed to cause the warp that we measured,” Volk said in a statement, citing no more than 1 or 2 percent chance that the warp was simply a statistical fluke of the Kuiper Belt objects (KBOs) sampled.
And it’s playing out to be a real signal than a mere fluke. Their calculations revealed that the object has sufficient gravitational influence to have such effect on farther KBOs. Across the given distance, hypothesizing that a planetary mass causes the warp is “not unreasonable,” Volk explained.
Could it possibly be the mysterious Planet 9 then?
Nope, as researchers clarified that the so-called planetary-mass object is too small and too close to be the same exact thing. Planet 9 is believed to lie 500 to 700 astronomical units (AU) from Earth, with a mass around 10 times that of our planet.
That’s too distant to influence the KBOs, and it has to be much closer than 100 AU to significantly affect them in that range, Volk said.
What happens to the search for Planet 9 now?
The Continuing Search For Other Worlds
Planet 9 was hypothesized as the ninth planet of the solar system as of January 2016.
Astronomers are yet to prove its existence, but speculations abound. A study early this year, for instance, proposed that Planet 9 could be a “rogue planet” or a free-moving body unbound to any particular star in the past, eventually getting snatched into the solar system through the gravitational pull of the sun.
Forbes noted that one way to look for these elusive bodies is to actually look at the gravitational tug they exert on other bodies. Neptune, according to the report, was discovered this way.
However, seeing the gravitational tug from more much distant worlds proves difficult, as the distances are bigger and the gravitational influences much weaker.
Recent surveys of outer worlds too seem to demonstrate that the clustering of the farthest Trans-Neptunian Objects (TNOs), which offers evidence of an existing super-Earth planet, was potentially because of detection bias, and the TNOs’ distribution itself does not back up the existence of a Planet 9.
This, though, is far from being the end of the search for solar system bodies. While there may not be a super-Earth, there could be a smaller one in the form of Planet 10. Astronomers are hopeful that the Large Synoptic Survey Telescope (LLST) currently being built in Chile will help scour the outer solar system for these worlds.
“There are a lot more KBOs out there — we just have not seen them yet,” Malhotra said.