Avi Loeb
Harvard chief astronomer Avi Loeb continues to stand by his alien spaceship theory. Pictured: Avi Loeb, Frank B. Baird, Jr. Professor of Science at Harvard University speaks on stage as Yuri Milner and Stephen Hawking host press conference to announce Breakthrough Starshot, a new space exploration initiative, at One World Observatory on April 12, 2016 in New York City. Getty Images/Bryan Bedder

One scientist is not backing down on his belief that the 'Oumuamua, a mysterious object that came from beyond the solar system, is an alien spaceship — or at least a piece of alien tech.

Avi Loeb, the chairman of Harvard University's astronomy department, caused a stir last year when he and his colleague Shmuel Bialy wrote a paper claiming that the interstellar object spotted by astronomers in Hawaii back in 2017, dubbed 'Oumuamua, which is Hawaiian for "scout," is a piece of extraterrestrial spacecraft technology.

"['Oumuamua] is a lightsail, floating in interstellar space as a debris from an advanced technological equipment,” he and Bialy wrote in a November paper that has been accepted for publishing in the Astrophysical Journal Letters.

Since releasing his shocking paper, Loeb has been criticized by other scientists, with Ohio State University astrophysicist Paul M. Sutter even calling their alien spacecraft claim insulting.

North Carolina State University astrophysicist Katie Mack, meanwhile, told the Verge that Loeb may have just proposed a theory that he didn't believe in just for the sake of putting it out into the world.

However, Loeb, who has been an Ivy League professor for 30 years and has published hundreds of astronomical papers, is still convinced that the 'Oumuamua may be artificially made and not just a space rock.

He recently told the Washington Post that 'Oumuamua is moving too fast for it to be an inert rock and that according to his calculations, it may be flying past the orbit of Jupiter right now. He explained that the object resembles a "kilometer-long obloid pancake" because it is very long but no more than 100 meters thick. 'Oumuamua is also so light that sunlight is pushing the object out of the solar system.

Loeb isn't insisting that the 'Oumuamua could only come from aliens, but he said he believes that only the extraterrestial technology explanation fits the data at the moment. But if someone proves him wrong about this, he is willing to take his words back

“Many people expected once there would be this publicity, I would back down,” Loeb told the Post. “If someone shows me evidence to the contrary, I will immediately back down.”

“It changes your perception on reality, just knowing that we’re not alone,” he continued. “We are fighting on borders, on resources. … It would make us feel part of planet Earth as a civilization rather than individual countries voting on Brexit.”