It’s an interstellar object known as 'Oumuamua, a moniker meant to reflect its standing as a messenger from the past, and the tale it has to tell certainly is an interesting one.
Scientists on Monday released a more detailed description of 'Oumuamua, more formally known as 1I/2017 U1, which was first spotted streaking across the cosmos on Oct. 19. The object, originally designated as an asteroid, is now categorized as a metallic (or rocky), dark red, elongated, interstellar body that’s unlike any known asteroid previously found in the solar system.
"For decades we've theorized that such interstellar objects are out there, and now -- for the first time -- we have direct evidence they exist," NASA's Thomas Zurbuchen said Monday in a news release.
'Oumuamua was first spotted heading back to interstellar space by scientists using the Pan-Starrs 1 telescope in Hawaii. Other astronomers then began observing it with instruments including the Very Large Telescope operated by the European Southern Observatory in Chile, and the Gemini Observatory’s twin optical/infrared telescopes in Hawaii and Chile.
"'Oumuamua may well have been wandering through the Milky Way, unattached to any star system, for hundreds of millions of years before its chance encounter with the Solar System," says the European Southern Observatory.
One of the key findings from the combined observations is that the brightness of the object varies dramatically as it spins on its axis, changing in luminosity by a factor of 10 every 7.3 hours.
Karen Meech explains the significance: “This unusually large variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape. We also found that it has a dark red colour, similar to objects in the outer Solar System, and confirmed that it is completely inert, without the faintest hint of dust around it.”
Scientists are still trying to pinpoint exactly where 'Oumuamua came from, with initial calculations suggesting it came from the direction of the star Vega.
However, even travelling at a breakneck speed of about 95,000 kilometres/hour, it took so long for the interstellar object to make the journey to our Solar System that Vega was not near that position when the asteroid was there about 300,000 years ago.
It’s estimated that an interstellar object like 1I/2017 U1 passes through our galactic neighborhood approximately once every year. But they’re fast, faint, and hard to see, so unless you have a world-class telescope, your stargazing time is probably better spent elsewhere.