It’s not a bird. It’s not a plane.
And it’s (probably) not an alien spacecraft sent to watch us, but a rock.
A team of international asteroid and comet experts, including two University of Hawaii astronomers, now agree that all available data on ‘Oumuamua ― the first recorded interstellar object to pass through the solar system ― strongly suggest it has “natural origins.”
Previously, astronomers had hypothesized that given its unique attributes, including its bizarre shape, the object could actually be a spacecraft sent from a distant civilization to snoop on our solar system.
But a 14-person research team reviewed the data further and determined that on closer inspection, ‘Oumuamua acted a lot like other small planetary bodies.
‘Oumuamua, which means “a scout or messenger that reaches out from the distant past” in Hawaiian, was discovered in October 2017 by the Pan-STARRS 1 telescope in the islands.
Scientists said it was traveling through space at 196,000 mph, and appears to accelerate before leaving our solar system. The research team behind the latest study, however, said that acceleration was relatively tiny and could be explained by gas or dust ejecting from the object.
The team also concluded that ‘Oumuamua rotates once in about seven hours and is red, which means it’s typical of other celestial bodies in our social system.
What is unusual: ʻOumuamua appears to have an extremely elongated shape, unlike any known object in our solar system.
The team’s findings appeared Monday in the journal Nature Astronomy.
“It was exciting and exhausting to coordinate all the ʻOumuamua observations with my co-authors from all around the world,” said Karen Meech, of the University of Hawaii’s Institute for Astronomy.
Added Robert Jedicke, of UH: “While ʻOumuamua’s interstellar origin makes it unique, many of its other properties are perfectly consistent with objects in our own solar system.”
The team seeking to learn more about ʻOumuamua also tried to figure out how it could have traveled to our solar system from its own. One leading theory is that it was ejected by a gas giant planet.
“We have never seen anything like ʻOumuamua in our solar system,” said Matthew Knight, of the University of Maryland, in a news release. “The alien spacecraft hypothesis is a fun idea, but our analysis suggests there is a whole host of natural phenomena that could explain it.”
The research team also believes that ʻOumuamua is the first of what they believe will be many interstellar visitors seen passing through our solar system thanks to stronger telescopes.