Harvard researchers discover extraterrestrial potential in a mysterious object – Harvard Gazette

"Oumuamua," whose name means "messenger from afar," was immediately sighted by astronomers in Hawaii: it immediately captured the imagination of scientists because it was the first known interstellar object to pass through the world. solar system. The mystery around the discovery quickly grew.

For starters, according to Loeb, his reflection of sunlight suggests that his shape is much more elongated or flattened than any known asteroid or comet, and his movement indicates that it comes from the so-called "local stallion" obtained by averaging randomly. movements of all nearby stars. According to Loeb, less than one out of every 500 local stars moves so slowly in this setting.

In addition, if 'Oumuamua comes from a population of similar objects on random trajectories, its discovery would require the production of 1,000 billion objects of this type per star in the Milky Way – far more than the theoretical calculations made by Loeb and his colleagues.

According to Loeb, by far the most intriguing sighting suggested that "Oumuamua was not just accelerating, but was moving away from its intended course.

"The differences are not important, only about one-tenth of a percent, but nevertheless, it's important," Loeb said. "The question is, what makes him deviate? We have observed deviations of this magnitude in comets when they experience degassing as the ice warms the sun, but there is no cometary tail around 'Oumuamua' and we do not see its rotation change as we would with degassing … I think it might be due to the sun's radiation pressure. "

The notion of using a solar sail to travel great distances is not unusual, said Loeb.

In 2010, a Japanese spacecraft called IKAROS demonstrated the first successful use of the technology. Loeb is the chairman of the Breakthrough Starshot project advisory board, which aims to launch a solar-powered probe to the nearest star system.

"It's possible that once a civilization has reached a certain technological maturity, it's a very common technological solution," said Loeb. "A rocket is limited at a certain speed … because you carry the fuel with you. But if you use light to push yourself, you are not limited in the same way. "

Today, 'Oumuamua is too far away to allow definitive answers to the questions raised by Loeb and other astronomers, and is going too fast to be pursued by probes launched from Earth. Loeb hopes the next opportunity will end with more answers.

"I hope that next time, when there will be an object like this, people will be intrigued and … we will do our best to understand what it is," he said. he continued. "It may be a natural object, and if it is, I would argue that it has so many unique characteristics that we should understand its origin and learn from it. But by then, all possibilities should be on the table. "

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