A mysterious object spotted floating through our solar system last year might be an alien spacecraft that was investigating Earth, according to Harvard astronomers.The astronomers suggested the theory in a recent research paper. The object, called Oumuamua, was first found by telescope in Hawaii in 2017.Researchers based their theory on the speed that the object traveled, which was around 196,000 mph.The Oumuamua is the first object seen in our solar system that is known to have originated elsewhere.