• Farfarout is a tiny object that's 140 AU away (one AU is the distance from the Earth to the sun).
• The previous furthest known object in our solar system, called simply Farout, was only 120 AU from here.
• Farfarout's orbit could reveal secrets of the outer solar system—including whether there's an unknown Planet Nine out there.
The universe has a way of surprising even its most ardent observers.
Scott Sheppard, an astronomer at the Carnegie Institution for Science in Washington, D.C., was scheduled to give a lecture on what was the furthest known object in the solar system. And then, just a day before his scheduled talk, he discovered an even further one.
“This is hot off the presses,” Shepard on February 21. “Yesterday it snowed so I had nothing to do, so I went looking through some of our data.” And then, aha.
The newly discovered object is called, appropriately, Farfarout. It replaces as the furthest known object in our solar system. The previous record holder orbited the sun at about 120 AU (one AU, or astronomical unit, is the distance from the Earth to the sun). Farfarout is a stunning 140 AU away.
Objects at this distance lie within the Kuiper Belt and are known as Kuiper Belt Objects (KBOs). The nearest familiar object to FarFarOut is Pluto, which is vast in comparison. Pluto is 1,400 miles (2,380 km) wide, while FarFarOut is made up of two lobes, each of them between 6 and 9 miles (10-15) wide.
"This is basically the leftovers from planet formation," Shepard said in his newly assembled presentation. "The object is probably telling us a lot about how planet formation occurred. Little objects come together and form bigger objects over time, and this is a frozen-in-place formation process."
Objects like FarFarOut are more than trivia answers. They can hint towards something larger looming in the far reaches of the solar system. Shepard and his team have no idea what FarFarOut's orbit looks like. But it's possible that the orbit could be influenced by a still-hypothesized Planet Nine or Planet X, a larger body hidden by the distant . which lies beyond the Kuiper Belt.
Shepard has been looking for Planet Nine for years. It will still take some time to figure out what the deal with FarFarOut is: Shepard estimates that it will take 20 months to get all the necessary data on the object. Who knows what he'll find between then and now.