Could Oumuamua Be an Extra-Terrestrial Solar Sail?
Basically, Shmuel Bialy and Abraham Loeb consider the possibility that ‘Oumuamua could in fact be a light sail, a form of spacecraft that relies on radiation pressure to generate propulsion — similar to what Breakthrough Starshot is working on. Similar to what is planned for Starshot, this light sail may been sent from another civilization to study our Solar System and look for signs of life. As Loeb explained to Universe Today via email: “We explain the excess acceleration of ‘Oumuamua away from the Sun as the result of the force that the Sunlight exerts on its surface. For this force to explain measured excess acceleration, the object needs to be extremely thin, of order a fraction of a millimeter in thickness but tens of meters in size. This makes the object lightweight for its surface area and allows it to act as a light-sail. Its origin could be either natural (in the interstellar medium or proto-planetary disks) or artificial (as a probe sent for a reconnaissance mission into the inner region of the Solar System).”