"This unusually big variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape", Meech said. They've dubbed this mysterious interstellar asteroid "Oumuamua".
The scientists also found that the asteroid is dense, possibly rocky or with high metal content, lacks significant amounts of water or ice, and that its surface is now dark and reddened due to the effects of irradiation from cosmic rays over millions of years. Now, they have determined that this object, named 'Oumuamua, is unlike anything normally found in the Solar System.
Observations suggest the object had been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years.
One of the things that makes this rock super special is that the rock is the FIRST to be discovered that formed in another solar system and travelled to our solar system.
According to NASA, both the Hubble and Spitzer telescopes are still tracking'Oumuamua. Our observations reveal the object to be asteroidal, with no hint of cometary activity despite an approach within 0.25 au of the Sun.
Since its discovery, the object has faded from view.
Observations from large ground-based telescopes will continue until the object becomes too faint to be detected, sometime after mid-December. Imminent upgrades to contemporary asteroid survey instruments and improved data processing techniques are likely to produce more interstellar objects in the upcoming years.
"This thing is very unusual", lead author Karen Meech, an astronomer at the University of Hawaii, which runs the telescope that spotted A/2017 U1, said in a press release.
The asteroid has been moving at an impressive speed of 59,000 miles an hour, per the release, and came from the same direction as Vega, a bright star once featured in the famous sci-fi film Contact. In addition to the technical name, the Pan-STARRS team dubbed it 'Oumuamua (pronounced oh MOO-uh MOO-uh), which is Hawaiian for "a messenger from afar arriving first". It was first spotted via a telescope in Hawaii, and upon further investigation, NASA scientists concluded that the astroid was the first interstellar object every discovered. NASA has announced it will pass Jupiter in May 2018, Saturn in January 2019, and when it exits the solar system it will be heading for the Pegasus constellation.
Alternatively, it might be that other star systems astronomers have already observed, which have exoplanets with metallic atmospheres (titanium, for example), might be more common than we expect.
After the discovery of the first interstellar object, astronomers are looking forward to upgrading these survey telescopes to detect smaller and fainter objects.