Astronomers last year discovered the asteroid Oumuamua who traveled through our solar system after coming from another star. While the cigar-shaped asteroid passed through our solar system, scientists began to theorize that asteroids could have come a long way away and then stopped. Experts have still discussed the discovery and a recent theory from experts at the Harvard Smithsonian Center for Astrophysics, Shmuel Bialy and Abraham Loeb, said that "Oumuamua may have been sent by foreigners to investigate other galaxies.
Professor Loeb told Universe Today: "We explain the excessive acceleration of" Oumuamua away from the sun as a result of the power of sunlight on the surface.
"In order for this force to explain measured excess acceleration, the object must be extremely thin to order a fraction of a millimeter in thickness but tens of meters in size.
"This makes the object easy for its surface and makes it possible to work as a light sail.
"The origin can be either natural (in the interstellar medium or proto-planetary discs) or artificial (as a probe sent for a reconnaissance mission in the sun's inner area)."
But the astronomer who discovered the asteroid, Robert Weryk, has criticized the alien theory, calling it "wild" and "exotic".
Weryk told CBC's afternoon operation: "I think it's a rest from another solar system. It was just something that happened to run into us, and we were lucky to have driven the telescope that night and looked in that direction.
"It has been theoretically predicted for decades, but we have never seen one. Until we see another, there are many questions we just can not answer."
Other astronomers have also criticized Prof Loeb's theory.
Alan Fitzsimmons, an astrophysician at Queens University, Belfast, recently said: "Like most researchers, I would love to be there to be convincing evidence of alien life, but it is not.
"It has already been found that its observed properties are consistent with a comet-like body protruding from another star system.
"And some of the arguments in this study are based on numbers of great uncertainties."
Katie Mack, an astrophysician at North Carolina State, also had a problem with the theory.
She wrote on Twitter: "What you must understand is: Scientists are happy to publish an outlandish idea if it has the least chance of not being wrong
"But until all other possibilities have been exhausted dozens of times over, the authors probably do not believe it."
The bizarre cigar-shaped spacecraft is believed to have been wandering among the stars for hundreds of millions of years and it is the first strange object to be seen in our solar system.
"Oumuamua is about 400 meters tall and is a dark red color and was discovered by the Pan-STARRS1 telescope in Hawaii on October 19, 2017 and travels at approximately 95,000 kilometers an hour.