A Harvard University scientist suggested that the interstellar asteroid Oumuamua is a space sail - an alien probe that accelerates using the pressure of the solar wind ions. Despite skepticism and criticism from other scientists, he continues to prove his case, believing that humanity is more than ever close to contact with another intelligent civilization. We tell how such optimism is justified and what a strange celestial body really is.
In all seriousness
American theoretical physicist and professor at Harvard University Abraham Loeb is a world-class astronomer. His research work covers a wide range of scientific fields, including the problem of the first stars in the Universe, the era of reionization, the formation of supermassive black holes, the search for extraterrestrial life, gravitational lensing involving planets, gamma-ray bursts, "21 cm cosmology", the Lyman-alpha forest as well as tidal destruction of stars and visualization of the "shadow" of black holes. The scientist was recognized as a pioneer in some areas around which entire communities of astrophysicists are now concentrated.
Abraham Avi Loeb.
In October 2018, Loeb made a speculation that stirred up the public and the scientific community, which turned out to be unpleasantly surprised. According to the astrophysicist, the asteroid Oumuamua, considered the first discovered interstellar object to visit the solar system, is an alien starship built in the form of a thin sail that catches the solar wind. This supposedly explains the fact that, moving away from the Sun, the asteroid had a speed slightly higher than predicted, despite the absence of a degassing process. During degassing from under the surface of a celestial body powerful jets of volatiles are ejected, which could contribute to the relative acceleration of the asteroid. In addition, Loeb pointed to a number of other anomalous phenomena to support his point.
Abnormal body
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Oumuamua was discovered on October 19, 2017 at a distance of 0.25 astronomical units from Earth (a quarter of the distance between the Sun and Earth). This asteroid differs from other similar objects with its unusual cigar-shaped shape and small thickness. Despite the fact that it came close enough to the Sun and contained a large amount of ice, astronomers did not notice any signs of vaporization. Despite this, leaving the solar system, the asteroid unexpectedly increased its speed, although scientists expected it to slow down.
The hypothesis about the artificial origin of the asteroid was too bold and controversial. Abraham Loeb could not help but know that his statement would cause criticism from colleagues who have fair objections. For example, according to Alan Fitzsimmons, an astrophysicist at the University of Queens, Northern Ireland, the asteroid's observed properties are consistent with the expected behavior of comet-like bodies ejected from another planetary system.
Paul M. Sutter of Ohio State University was more blunt. "Oumuamua is not a spaceship, and the authors of the article are insulting to real scientific research by their mere assumption," he wrote on his Twitter page. Astrophysicist Ethan Siegel called Loeb's conjecture "a shocking example of unwarranted sensationalism." And astronomer Katie Mack from the University of North Carolina suggested that Loeb was just trolling everyone.
Degassing of the comet nucleus.
However, Loeb is clearly not a newbie in scientific disputes, and he cannot be attributed to scientific freaks because of his significant scientific reputation, - began to fiercely defend his hypothesis, rejecting the version that Oumuamua is a comet or an asteroid. According to him, the space object can be an active spacecraft or its fragment one kilometer long and one millimeter thick. He supposedly moves too fast to be an inert piece of rock. And if it was created along with other similar objects, then beyond the solar system there could be billions of probes exploring every star in the galaxy.
Loeb believes that the universe is literally inundated with space debris left over from intelligent beings. He also accused other scientists of not having the courage to admit that Oumuamua possesses rather extraordinary properties. "Scientists have been given the opportunity to take risks without fear of losing their jobs," Fox News quoted him as saying. In response, critics noted that there is a difference between a testable hypothesis and unfounded speculation.
Finger to the sky
Loeb is easily suspected of being a victim of his own prejudice. He is literally obsessed with the idea that there are alien civilizations with whom it is imperative to establish contact. In his opinion, the search for extraterrestrial life is much less speculative than the idea of the existence of invisible dark matter, which makes up 85 percent of all matter in the universe. Loeb is an ardent supporter of the Breakthrough Starshot project by Russian billionaire Yuri Milner, which proposes the creation of an entire fleet of interstellar spaceships with solar sail. It is believed that these probes will develop 20 percent the speed of light and reach the closest star to the Sun in a couple of decades.
Loeb, however, realizes that his hypothesis could turn out to be career suicide for him if it is proved that it is wrong. True, he is not at all afraid of this and is proud of his unusual approach to science, criticizing "mainstream research" and comparing it to working in an office. If he is relieved of his administrative duties, he will have more time to study science. However, if he nevertheless turns out to be right (and he faithfully believes in this), then this will be the greatest achievement of humanity. Every person on Earth, the scientist believes, will feel like a part of one huge intelligent civilization, and not of separate countries.
Oumuamua's flight path.
In other words, the fan of the search for extraterrestrial intelligence, Abraham Loeb, tired of the routine, decided to play all-in, defending the most incredible version, in the hope that he will hit the sky. However, as proponents of the scientific approach like to say, extraordinary claims require extraordinary evidence, and in the case of Oumuamua there are a number of more plausible hypotheses explaining the anomalies. For example, an asteroid is accelerated by absorbing and re-emitting solar radiation, or it really is a solar sail - only natural, not artificial.
There is more and more evidence that Oumuamua is actually an asteroid, albeit an unusual one. So, scientists at NASA's Jet Propulsion Laboratory came to the conclusion that an unusual celestial body is the remnant of an interstellar comet, which disintegrated before approaching the Sun, leaving behind an elongated rocky fragment. The simulation results showed that the characteristics of the rotation of this fragment around its axis, the absence of degassing and the shape correspond to what is observed in the case of Oumuamua. In addition, the acceleration of the asteroid must indeed be explained by the pressure of the solar wind.
Alexander Enikeev
