Astronomers have cataloged eight planets, 6,500 comets and more than 525,000 asteroids, but Oumuamua is one of a kind. The elongated space object, which was discovered speeding past the sun in 2017, is the only celestial body known to have visited our solar system from another.
Oumuamua is believed to be an exotic type of comet or asteroid, but it’s such an oddity that some astronomers have speculated it could be an alien spacecraft.
Robert Weryck, a postdoctoral researcher at the University of Hawaii’s Institute for Astronomy, found Oumuamua by accident. On Oct. 19, 2017, he was using the Pan-STARRS telescope on Maui to scan the skies for Earth-approaching asteroids. At first he thought he had found one. “But then I was able to locate it in two images from the previous night,” he said, “and when I combined them together the orbit didn’t make sense.”
After collecting additional observations, Weryck and his colleague Marco Micheli concluded that the object’s trajectory indicated that it had originated “from outside our solar system.”
Astronomers had been seeking such a visitor for decades. “What’s most surprising is that we’ve never seen interstellar objects pass through before,” Karen Meech, another astronomer at the institute, told NASA a week after the discovery.
… To Read more, please click here