Mystery Object Could Be First Visitor From Another Solar System

A little over a week ago, the University of Hawaii's Pan-STARRS 1 telescope located in Maui began tracking an object racing through our solar system that wasn't behaving like anything they'd seen before. 

A postdoctoral researcher with the University of Hawaii Institute for Astronomy (IfA) was the first to identify the UFO zooming through our solar system and quickly realized there was something different.

"Its motion could not be explained using either a normal solar system asteroid or comet orbit," Rob Weryk said. 

The object, designated as A/2017 U1 - is less than a quarter mile in diameter and moving remarkably fast.  But what really tripped Weryk up was its orbit. Seeking answers, he contacted IfA graduate astronomer Marco Micheli who had a similar realization after examining his own images taken at the European Space Agency's telescope on the Canary Islands. 

The pair combined their data and realized that not only was this object strange, it was literally from another solar system. 

"This is the most extreme orbit I have ever seen," said Davide Farnocchia, a scientist at NASA's Center for Near-Earth Object Studies (CNEOS) at the agency's Jet Propulsion Laboratory in Pasadena, California. "It is going extremely fast and on such a trajectory that we can say with confidence that this object is on its way out of the solar system and not coming back."

NASA says astronomers all over the world are tracking the object to get more data to confirm A/2017 U1 is an interstellar object. Using the data obtained so far, the CNEOS team plotted the object's trajectory from its origin, to its next possible destination. 

According to their calculations, A/2017 U1 came from the direction of the constellation Lyra speeding through space at a brisk 15.8 miles per second. As it approached our Sun, A/2017 U1 fell from above the ecliptic plane, crossing under the ecliptic on September 2nd. Pulled by the Sun's gravity, A/2017 U1 raced under the solar system, where it passed under Earth's orbit on October 14th. 

(Don't worry, it was about 60 times the distance to the moon, or 14,916,840 miles away when it passed by us).

"We have long suspected that these objects should exist, because during the process of planet formation a lot of material should be ejected from planetary systems. What's most surprising is that we've never seen interstellar objects pass through before," said Karen Meech, an astronomer at the IfA specializing in small bodies and their connection to solar system formation.

The small comet (or asteroid) is now headed toward the constellation Pegasus where it will continue on its lonely interstellar adventure and hopefully, eventually, get a better name.