Astronomers spot most distant object so far in solar system

Astronomers have spotted what they believe to be the most distant object ever seen in our solar system.

The dwarf planet, known for now simply as V774104, is more than 100 times farther from the sun than we are. Astronomers aren't sure what it's doing out there, but they're hoping follow-up studies of its orbit will teach them more.

V774104 was first noticed in mid-October. Astronomer Scott Sheppard and his colleagues were using the Subaru telescope in Hawaii to hunt for faint, distant objects orbiting the sun. Basically they were just pointing the building-sized telescope at random patches of sky to try to catch anything moving out there.

"Generally we're just randomly shooting for the most part, because we don't know where these objects might be," he says.

They recorded loads of pictures. A computer sifted through the images, looking for anything that seemed to be moving. Then the program flagged the interesting photos for follow-up. Sheppard put the data on his laptop and headed home to Washington.

That's when he made the discovery.

"I remember I was flying back on the plane, looking through the data, and I remember when this popped up on the screen, my eyes opened up," he says.

It was just a little pinprick of light, but it was moving slowly across the sky. Doing the math, Sheppard realized this could very well be the most distant thing ever seen in our solar system.

V774104 is "three times farther than Pluto is from the sun," he says.

Sheppard announced the discovery Monday at the American Astronomical Society's Division of Planetary Sciences meeting in National Harbor, Maryland.

The new world is tiny, much smaller than our own moon. Sheppard thinks it's probably made of ice. But the real question is how did it get all the way out there?

One theory is a rogue planet was thrown out of the early solar system and dragged this poor little guy along.

"If a large planet formed in our solar system and got tossed out, it could pull objects out with it as it was leaving our solar system and kind of drop objects along the way like Hansel and Gretel," he says.

It's also possible this world came from another star system and ended up around the sun.

Sheppard is trying to find out more by making further observations of the new dwarf planet's orbit. Those observations might also show that it's not quite as far away as initially thought. But even if it doesn't break a record, Sheppard isn't worried.

"This object is basically going to be interesting no matter what we find its orbit to be," he says. Copyright 2019 NPR. To see more, visit https://www.npr.org.