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'Oumuamua: Comet or Alien Probe?

'Oumuamua: Comet or Alien Probe?

But its "flattened, elongated shape and the way it accelerated on its way through the solar system set it apart from conventional asteroids and comets", reports NBC News.

It was moving at 59,030mph when it was first tracked by scientists.

Harvard researchers have now said it "may be a fully operational probe sent intentionally to Earth's vicinity by an alien civilisation".

The cigar-shaped rock is now speeding through the galaxy and is the first known interstellar object to enter our solar system.

The object was said to be 10 times longer than it is wide and it traveled at speeds of almost 200,000 miles per hour.

Shmuel Bialy and Abraham Loeb, two astronomers from the Harvard Smithsonian Centre for Astrophysics, suggested the cigar-shaped object - given the Hawaiian name 'Oumuamua, which NASA notes "means a messenger from afar arriving first" - could have been a discarded light sail of extra-terrestrial origin, perhaps sent here on goal.

In a letter published in The Astrophysical Journal Letters on 12 November, the researchers add that Oumuamua could be a spacecraft pushed along by light falling on its surface. According to the study, "this would account for the various anomalies of 'Oumuamua, such as the unusual geometry inferred from its lightcurve, its low thermal emission, suggesting high reflectivity, and its deviation from a Keplerian orbit without any sign of a cometary tail or spin-up torques".

Mr Loeb is an adviser to Breakthrough Starshot, an initiative that plans to send a fleet of tiny laser-powered lightsail craft to the nearest star system.

It's also entirely possible - perhaps more possible - that the object isn't part of a far-flung alien race's attempts to investigate the (other) occupants of the Milky Way.

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Alongside Shmuel Bialy, a postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics, acknowledges that the alien spacecraft theory is an "exotic" one.

In their paper, the Harvard scientists say the only way to know for sure is to keep watch and see what else shows up in our solar system.

"Not 'where is the lack of evidence so that I can fit in any hypothesis that I like?"

Scientists first called the object an asteroid, then later deemed it a mildly active comet.

Oumuamua has left the solar system and is no longer visible, the news outlet noted.

Of course, the pair aren't claiming that Oumuamua's definitely of alien origin.

"Any functional spacecraft would nearly certainly retract its solar sail once in interstellar space to prevent damage", Mr Jackson said.

"Two very capable, very bright astronomers, from a very credible organization, Harvard, have come out with the notion that Oumuamua could be alien in origin", Diamond said.