The presence of an unidentified object hurtling through our solar system recently prompted a call to action from observatories throughout the world. NASA has confirmed that it’s the first object to arrive from another star – and it may be as long as a quarter mile. While the rocky asteroid, dubbed ‘Oumuamua, is definitely not piloted by aliens, it could give us clues into the formation of other solar systems.
In late October, scientists thought they might have observed an object that came from outside the solar system with the aid of the University of Hawaii’s Pan-STARRS1 telescope. The International Astronomical Union reclassified the object from a comet to an interstellar asteroid, per a November 14 release. NASA’s Science Mission Directorate associate administrator Thomas Zurbuchen said in a November 20 press release: “For decades we’ve theorized that such interstellar objects are out there, and now – for the first time – we have direct evidence they exist.”
Yesterday the journal Nature published a study on the find, led by scientists at the Institute for Astronomy in Hawaii. NASA helped fund the work. The bizarre asteroid could have been “wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with our star system,” according to the agency.
‘Oumuamua – Hawaiian for “a messenger from afar arriving first” – has a slightly reddish hue, and is around 10 times as long as it is wide, according to NASA, which said the asteroid’s aspect ratio is bigger than any other asteroid or comet we’ve ever observed. And it varies widely in brightness: “by a factor of 10 as it spins on its axis every 7.3 hours.” It’s likely dense, comprised of metals or rock, without ice or water, and could have been reddened by irradiation from cosmic rays.
A few of Earth’s big ground-based telescopes are still tracking ‘Oumuamua. It’s around 124 million miles away from our planet and will probably be too faint for detection around mid-December. It will head for the constellation Pegasus after exiting our solar system.