Oumuamua: Strange interstellar object may be an alien sail, say Harvard researchers

Strange object 'Oumuamua' could be an alien sail sent from another civilisation to look for signs of life, according to a new study report titled "Could Solar Radiation Pressure Explain 'Oumuamua's Peculiar Acceleration" conducted by Shmuel Bialy and Abraham Loeb, astronomers at the Harvard Smithsonian Centre for Astrophysics. Oumuamua, spotted last year was about a kilometre long with strange reddish in colour and appeared to have properties that belong to both comets and asteroids.

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"Considering an artificial origin, one possibility is that 'Oumuamua is a light sail, floating in interstellar space as a debris from an advanced technological equipment. Alternatively, a more exotic scenario is that 'Oumuamua may be a fully operational probe sent intentionally to Earth vicinity by an alien civilization," wrote the researchers in the study. 

Scientists reviewed data gathered by the Pan-STARRS-1 survey on 'Oumuamua's closest flight to the sun in September 2017 and took notice that the object gained speed instead of slowing down. The scientists said this was caused by the rock outgassing, releasing gas that was stuck inside it, according to reports.

"We explain the excess acceleration of ‘Oumuamua away from the sun as the result of the force that the sunlight exerts on its surface, Loeb said while speaking to Universe Today.

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"For this force to explain measured excess acceleration, the object needs to be extremely thin, of order a fraction of a millimetre in thickness but tens of meters in size. "This makes the object lightweight for its surface area and allows it to act as a light sail,” he said.

"Its origin could be either natural (in the interstellar medium or proto-planetary disks) or artificial (as a probe sent for a reconnaissance mission into the inner region of the solar system)," he added.

The two scientists admitted that even if their theory turned out to be true, then there was still the possibility that it was just a "defunct sail floating under the influence of gravity and stellar radiation", he said.