Last year, astronomers spotted something really odd in the vast reaches of space. It was our first known interstellar visitor. It was detected when it flashed past the Sun in October last year. It was named ‘Oumuamua’ – Hawaiian for messenger.
The Pan-STAARS-1 telescope in Hawaii announced that the discovered object was really odd. It was elongated. It was about a kilometre long. Its colour was of a strange reddish tinge. It displayed properties that belong to both comets and asteroids.
A new study by two Harvard Smithsonian Centre for Astrophysics astronomers have postulated that Oumuamua may have been an alien object – a light sail.
This study was presented by Shmuel Baily and Professor Abraham Loeb. Professor Loeb is a committee member of Breakthrough Starshot committee. The object was found to have a very high density. This indicates that it was an object made of rock or metal.
When it skimmed past the Sun, no gas cloud tail was observed as would have been the case in the event that it was a comet. But through a spectral analysis, it was observed that the object was much icier and should have made a gas cloud tail. But it didn’t.
Another interesting factor was the speed of the object. After passing the sun, it actually gained speed instead of losing it. The Sun’s gravity should have led to a loss in speed of the object. The speed-up would have been natural if it was a comet that vented gas as it passed by the sun. But it had no tail. The astronomers also said that such form of cometic ‘outgassing’ would have quickly changed the nature of Oumuamua’s spin. But this was also not observed.
With these anomalies, Loeb and Baily suggest that only one viable alternative hypothesis remains – that it is a mechanical light sail, designed to use starlight to propel it through space. This concept is similar to one that Breakthrough Starshot is working on. Thus, this hypothesis is not a long shot. It is quite possible.
