© AFP / European Southern Observatory / M. KornmesserAn artist's impression of Oumuama, the first interstellar object known to enter our solar system
The research letter, by two Harvard astronomers, admitted that while it was an "exotic scenario", the cigar-shaped rock named 'Oumuamua' "may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization."
Oumuamua, the first known interstellar object to enter our solar system, is 1,300 feet long (400 meters) long and about 130 feet wide. First observed by space telescopes in October 2017, the pointy space rock picked up speed when passing the Sun - making the researchers think it may run on sunlight. They say this "unexplained phenomena" means it would have to have a "very large surface and be very thin", which they say is "not encountered in nature".
Their paper is due to be published in 'Astrophysical Journal Letters' on November 12.
Now, that theory has been challenged, as a figment of an overly active imagination, by scientists who say it's a nice idea, but simply not accurate.
"Like most scientists, I would love there to be convincing evidence of alien life, but this isn't it," Alan Fitzsimmons, an astrophysicist at Queen's University, Belfast, told the AFP.
Fitzsimmons added that Oumuamua's observed characteristics have already been shown as "consistent with a comet-like body ejected from another star system", while "some of the arguments in this study are based on numbers with large uncertainties."
That sentiment is shared by Katie Mack, an astrophysicist at North Carolina State, who tweeted that excited alien hunters need to understand that "scientists are perfectly happy to publish an outlandish idea if it has even the tiniest sliver of a chance of not being wrong."
"But until every other possibility has been exhausted dozen times over, even the authors probably don't believe it," she cautioned.
Coronal mass ejections may possibly induce the coalescence of a massive solid object from unconsolidated rocky debris or rupture a larger asteroid. A C-type composition (carbonaceous chondrites) or ureilite clan object can be inferred from thermal emission/reflectivity, and ureilites are known to have scale-free fragmental aspect ratios similar to that inferred for Oumuamua, being highly shocked and dominated by compression melt and granular mosaicism. C-type asteroids commonly have odd elongated shapes. [Link]
Collisions between multiple asteroid bodies within the <0.26 AU perihelion domain from which Oumuamua was observed may also be perturbed by CME shocks due to solar flare nonequilibrium emission and CME shock interaction with interplanetary dust and small asteroids during the months Oumuamua was observed.
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