Scientists are still disconcerting the interstellar visitor of last year, "Oumuamua, and the last theory will surely excite UFO believers, according to a new paper published by the astronomers of Harvard University, the gigantic rock at The form of cigar that has swung in and out of our solar system in October 2017 has some strange properties that suggest it was an alien spacecraft, and while the unique physical properties of Oumuamua have prompted some scientists to speculate on the aliens, others scientists are not convinced or even worried about the effect of such conjectures.
"& # 39; Oumuamua could be a fully operational probe sent intentionally close to Earth from an alien civilization," wrote the authors Abraham Loeb, professor and president of astronomy, and Shmuel Bialy, a postdoctoral scholar, both at the Center of Harvard-Smithsonian astrophysics.
& # 39; Oumuamua, which is Hawaiian for "an object from afar," was first observed by a postdoctoral researcher at the University of Hawaii who was sifting the flow of data from the astronomical detection of the sky of Pan-STARRS. The researcher noticed that the object was very long, like a stick, with a long axis 10 times longer than its short axis. The researchers suggested that its shape would minimize abrasion from interstellar gas and dust, making it an ideal form for an interstellar spacecraft. Then, in May, an article published in the Monthlyapers magazine of the Royal Astronomical Society suggested that "Oumuamua moved to our solar system as a result of a gravitational sling of a binary star system.
The researchers landed on the last unearthly conclusion focusing on one of the most interesting properties of rock: its unexpected acceleration trajectory after passing the sun, which suggests it was driven by sunlight. Since there were no observed signs of cometary activity – such as a cometary tail, or lines of absorption of gas emissions – the possibility that it could be a comet was ruled out by Harvard researchers.
"& # 39; Oumuamua deviates from a trajectory dictated solely by the gravity of the Sun," Loeb told Salon in a statement. "This could be the result of a cometary degeneration, but there is no evidence for a cometary tail around it.In addition, comets change the period of their rotation and no change has been detected for" Oumuamua ".
After elaborating the hypothesis through a mathematical model, the authors hypothesize that the non-gravitational acceleration of "Oumuamua was due to the pressure of solar radiation.
"The only other explanation that comes to mind is the extra force exerted on" Oumuamua by sunlight "Loeb told Salon. "To be effective," Oumuamua must have a thickness of less than a millimeter, like a sail, which led us to suggest that it could be a light sail produced by an alien civilization. "
Light sailing propulsion systems have been created on Earth and their origins date back to the 1970s, when NASA played with the idea of flying a solar sail to Halley's comet. The project has been canceled, but the non-profit Planetary Society has since successfully established its program to build light-powered spacecraft.
Yet it is precisely this speculation that is causing a little discussion among scientists. Some researchers tell Salon the theory that "Oumuamua is an alien and imperfect light sail, and falls outside the realm of science, as it is unverifiable.
"In science we have to be extremely careful about our hypotheses," said an Ohio State University astrophysicist at Salon Paul Sutter. "My main criticism is that as soon as you introduce the aliens as a hypothesis stop doing science, because the aliens are able to do whatever they want".
Sutter said there is no way to test such a hypothesis.
"We are free to have any ideas we want, and crazy ideas are welcome, but they must be testable," said Sutter. "From [aliens are] always available you can never exclude it, that's why you can not do science with it. "
Uncertainty and the strange behavior of Oumuamua have led researchers to speculate on an extraterrestrial origin, Sutter said, adding that scientists should be more patient or accept that they will never know what foreign rock is this time .
"Our only hope is that & # 39; Oumuamua is not the only one out there, and that there are other random rocks tumbling through our solar system, and we hope we can find Oumuamua's cousin watching or the great-aunt [next], "He said.
Seth Shostak, a senior astronomer in search of extraterrestrial intelligence (SETI), told Salon that the theory could be "an exotic solution to what could be a very trivial situation".
"It could be the solar sail of someone who has just wandered into our solar system or one who has deliberately targeted ours, [but] you can not say it's not true because there's no way to prove it's true, "Shostak told Salon.
Shostak added that if it is an alien spacecraft that has been deliberately sent, it is worth noting that it has not approached the Earth very much.
"You might think it would be an interesting goal for them," he said. "Come in, swing around the sun and come back, it's like someone interesting to walk into the neighborhood, walk near your house and do not knock on the door or anything, so I do not understand."
Dr. Michael Wall, senior writer of Space.com and author of the upcoming book "Out There", said while thinking that it is unlikely that Oumuamua is an alien spacecraft, the possibility should not be completely ruled out.
"I do not think it's likely, but the aliens must be the last explanation," he said. "First you have to exhaust all the natural explanations, but I do not think it should be rejected."
Since nothing like Oumuamua has been observed in our solar system, natural explanations could still be unknown to humans.
"It's very likely that we do not have enough information and we probably will never do it," Wall said. "It's interesting, but it just shows that there's a fine line we have to walk between being too quick and too gullible."
At the end of the day, this article was quite the topic of conversation among many scientists. Loeb told Salon he did not expect the newspaper to attract so much attention.
"I'm glad to see the enthusiasm for the document, but it was not written for this purpose," Loeb said. "We have just followed the standard practice of scientific research".
Nicole Karlis is a journalist at the Salon. You cover health, science, technology and gender policies. Tweet her @nicolekarlis.
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