A mysterious cigar-shaped object that astronomers spotted in the solar system last year could be an artifact of an alien civilization sent to explore Earth's neighborhood, according to two Harvard astronomers.
The researchers said that the non-gravitational acceleration exhibited by the object called Oumuamua can be explained by the effect of solar radiation pressure on a candle of light, a candle pushed forward, reflecting the sunlight.
A group of Hawaiian astronomers spotted the object on Oct. 19 last year and noticed in a few days its unusual features – a dark red tone and a very elongated shape, about 800m long – and a trajectory that indicated an origin outside the object. solar system. "Oumuamua" means "scout" in Hawaiian.
Groups of astronomers from Europe and America, who watched the rapidly disappearing object as it moved away from the sun, debated whether it was an asteroid or a comet.
Abraham Loeb, professor and president of astronomy, and Shmuel Bialy, a postdoctoral student at the Harvard Smithsonian Center for Astrophysics, in an article submitted to The Astrophysical Journal Letters has now brought a new angle to this discourse.
"Our work suggests that the first evidence of extraterrestrial technology may have just passed Earth last year," said Loeb, who is also director of the Harvard Institute of Theory and Computing at The Telegraph via e-mail.
Scientists from Europe, Israel and the United States in June this year, with multiple observations, reported an acceleration of Oumuamua that could not be explained by the gravitational effects of the Sun or other objects in the solar system.
In an article published in the journal Nature, scientists attributed the acceleration to the gas emissions that occur when ice in a comet vaporizes through the heat of the sun.
But no cometary tail was seen around Oumuamua. Nor did the astronomers observe the variations in their rotation that the external release of comet gas would have produced.
Loeb and Bialy have proposed that the non-gravitational acceleration of Oumuamua may have been produced by a light candle. They pointed out that candles with similar dimensions of light have already been designed and built by our own civilization. In 2010, Japanese engineers launched a sailboat called Ikaros.
The Harvard astronomer article shows that a light candle with a thickness of only 0.3 mm to 0.9 mm could survive a long journey through interstellar space, unharmed by probable collisions with atoms or dust particles.
"One possibility is that Oumuamua is a light candle floating in interstellar space as a remnant of advanced technological equipment," they wrote in their article, citing how earlier studies proposed light candles for interstellar travel.
"Alternatively, a more exotic scenario is that Oumuamua may be a fully operational spacecraft intentionally sent into the vicinity of Earth by an alien civilization," they said.
Astronomers said that Oumuamua was inferred to have an elongated shape, not observed in any known asteroid or comet. Information about its shape derives from the variation of reflected sunlight as it rotates, Loeb said.
Even a thin sheet that is folded like an umbrella may look from a distance, similar to a rotating cigar based on the variation of sunlight, he said.
Bialy said the current observations do not rule out pancake-like geometry. Studies re-examining the light signals suggest more carefully that Oumuamua can be very elongated in the form of cigar to pancake.
"What is clear is that it can not have a shape that is almost spherical – like the normal rocks we know," he said.
Loeb said that the mystery of the origin of Oumuamua remains. "It is not clear whether it can be a defunct or functional waste. Radio observatories have failed to detect any transmission of it (with instruments capable of detecting transmissions) at an energy level of more than a tenth of a single cell, "he said.
Astronomers have suggested stepping up surveillance of similar objects. "Since it is too late to imagine Oumuamua with existing telescopes or to chase them with chemical rockets," they wrote, "their probable origins and properties could only be deciphered by the search for other objects of their kind in the future."