That interstellar asteroid is even weirder than we thought

The asteroid, discovered last month, lives up to its alien reputation as scientists reveal its bizarre traits and give it a proper name.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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This artist's impression shows Oumuamua, an interstellar asteroid.

ESO/M. Kornmesser

Our solar system recently had a very strange visitor. For the first time ever, scientists last month spotted an interstellar object invading our part of space. Astronomers have revealed more details about the now-confirmed interstellar interloper and it's just plain weird.

The Pan-Starrs 1 telescope in Hawaii first spotted the object on Oct. 19 when it was already heading back to interstellar space. Astronomers rushed to make observations. An artist's impression shows a very elongated shape, different from any known asteroids. Scientists estimate it's about 1,300 feet (400 meters) in length. 

"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. By studying space objects like this one, researchers hope to find clues to the formation of other solar systems.

Originally named A/2017 U1, it now has the official moniker "Oumuamua," which refers to its distant origin as a messenger from the past. 

"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, which used its Very Large Telescope in Chile to observe the object.


This composite image of Oumuamua from the Gemini Observatory was made from 192 images.

Gemini Observatory/AURA/NSF

The Gemini Observatory, a collaboration between telescopes in Hawaii and Chile, also got in on the action, resulting in a color composite image of Oumuamua.

University of Hawaii astronomer Karen Meech says the rapidly rotating asteroid has a "complex, convoluted shape," is dark red in color and is "completely inert, without the faintest hint of dust around it." 

Meech and an international research team published their findings Monday in the journal Nature with the title "A brief visit from a red and extremely elongated interstellar asteroid."

The International Astronomical Union, which is responsible for cataloging the names of space objects, also gave the asteroid its very first "I" for "interstellar" designation, which shifts its formal name from A/2017 U1 (with the "A" standing for "asteroid") to "1I/2017 U1."

Scientists expect our solar system regularly receives interstellar visitors like this one, but they are faint and extremely hard to find. That makes Oumuamua all the more special. 

Update, Nov. 20 at 11:05 a.m. PT: This story has been updated to include a quote from NASA.  

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