Two New Planets Found? 'Planet X,' Possible Super-Earth Spotted, Astronomers Claim

For decades, astronomers have been searching for a distant and mysterious planet they believe lurks on the furthest edge of our solar system. They've called it "Planet X," and a group of scientists just announced they may have found it.

The astronomers revealed their discovery to the world on Tuesday to much skepticism and criticism, not excitement, from colleagues, the Washington Post reported. The group released two papers about the discovery, one announcing they'd spotted "the most distant object of the solar system" and another announcing a "possible new solar system object."

Both were spied from a group of radio dishes in the Chilean Andes called the Atacama Large Millimeter/submillimeter Array (ALMA), Scientific American reported.

To understand the significance of this announcement -- and, therefore, the level of scrutiny it has inspired -- you have to know a bit about the search for Planet X.

Astronomers believe in Planet X because something "big and dark," as yet unseen, has enough gravitational influence to mess up the orbits of objects that we do know exist. In fact, Planet X has been blamed for some irregularities in the orbits of Uranus and Neptune.

In 1846, scientists looked for Planet X beyond Uranus. They found Neptune. When they looked for Planet X beyond Neptune in 1930, they found Pluto. And in searching for the mystery object beyond Pluto, astronomers have found tons of new and Pluto-like "trans-Neptunian objects" -- or "big things" beyond Neptune.

So the stakes are quite high, and an announcement that there are two contenders for Planet X, if true, would be incredibly exciting.

The astronomers who've made this incredible claim only saw these mysterious bodies a couple times. At first, they figured they were just glows from a distant background galaxy. Over a period of months, they took a few pictures, and they discovered that both of these objects appeared to move against "fixed" background stars. To them, this hinted that the objects, whatever they were, are pretty close to our solar system.

They call one of these Planet X contenders "Gna," named after a Nordic messenger goddess. It was seen next to the star W Aquilae and could be an asteroid-like object about the size of Ireland, hanging out in the neighborhood between Saturn and Uranus. It could also be a much more distant and undiscovered Neptune-sized planet or a brown dwarf (failed star) the size of Jupiter.

Planet X and possible super Earth found?
[Image via MarcelClemens/Shutterstock]

The other Planet X contender hasn't yet been given a name and appeared around a nearby star system called Alpha Centauri. It could also be a brown dwarf or, even cooler, a super-Earth six times more distant than Pluto. Or it could just be a gargantuan ice chunk.

A super-Earth is a planet larger than ours but smaller than Neptune, and the chances that these astronomers have spotted one are slim, Discover reported. It's not reasonable to believe, the argument goes, that these people just so happened to be looking at the sky at just the right time to see it. The more likely truth about this Planet X contender and super-Earth is that it's just an icy object floating around Pluto in the Kuiper Belt.

And here's another mark against the possibility that the elusive and mythical Planet X has been found: NASA took a good, hard look already. Their Wide-field Infrared Survey Explorer space telescope did a thorough search of the sky last year for additional planets and found nothing. This doesn't rule out the possibility that a super-Earth has been found, but it makes it less likely.

Fellow astronomers have been pretty brutal in responding to this new claim, calling the papers on the find, which were posted online before being vetted, embarrassing. But Wouter Vlemmings, a Swedish astronomer involved in the finding, said he hopes colleagues will come forward with extra instruments to observe that distant blip he saw.

So maybe Planet X will be spotted after all.

[Image via Vadim Sadovski/Shutterstock]