Distant object at edge of Solar System is an ancient fragment from 4.5 billion years ago

Doyle Rice

It's a rather uninspiring object, with no moons, rings or dust clouds in orbit around it; nor is there any evidence of an atmosphere.

But this distant space rock at the far edge of our Solar System is actually an ancient relic that's remained largely untouched – even by the heat of the Sun – since its formation roughly 4.5 billion years ago, a new study said.

The unassuming, 20-mile-long object, which looks like a snowman that's been flattened like a pancake, is informally known as "Ultima Thule."

Thus, it preserves clues about the early history of the Solar System. 

Earlier this year, on New Year's Day, NASA's unmanned New Horizons spacecraft conducted a flyby of the object, which is officially known as MU69. Data from the flyby continues to be received and analyzed by scientists here on Earth.

“The New Horizons flyby of MU69 is humanity's first look at one of the building blocks of our Solar System,” the University of Virginia's Anne Verbiscer, one of the co-authors of the study, told Forbes. “We knew very little about this object before the flyby.”

According to the new study, it's actually two big rocks that apparently merged rather gently: "All available evidence indicates that MU69 is .... the product of a gentle collision or merger of two independently formed bodies," the study said. 

The object is out in the Kuiper Belt, a group of rocks and ice at the far reaches of our Solar System. According to CNET, Kuiper Belt objects orbit the sun so far out they may wander in the frigid void for billions of years undisturbed and therefore unchanged since the Solar System formed.

"New Horizons is like a time machine, taking us back to the birth of the solar system," Jeff Moore of NASA’s Ames Research Center, a study co-author, said earlier this year. "We are seeing a physical representation of the beginning of planetary formation, frozen in time.

"Studying Ultima Thule is helping us understand how planets form – both those in our own Solar System and those orbiting other stars in our galaxy," Moore said.

The space rock is roughly 1 billion miles away from Pluto – making it the most distant object ever visited by a spacecraft. It's also about 4 billion miles from the sun, and takes almost 300 years to complete an orbit.

Ultima Thule was first discovered in 2014 by astronomers using the Hubble Space Telescope. 

Thursday's study was published in the peer-reviewed journal Science, a publication of the American Association for the Advancement of Science.

This article originally appeared on USA TODAY: Distant object at edge of Solar System is an ancient fragment from 4.5 billion years ago