For the first time, astronomers think they’ve spotted a foreign object in our solar system. Something that came from elsewhere in the galaxy. A/2017 U1, as it’s currently known, was first spotted on October 19 by the University of Hawaii’s Pan-STARRS 1 telescope. A/2017 U1 is estimated to be under 400m in diameter.
While the planets and most other objects orbit the sun on a plane, A/2017 U1 came flying in from almost directly above. It passed inside Mercury’s orbit on September 2, and was pulled into a hairpin turn by the Sun’s gravity.
“We’ve never seen interstellar objects pass through before,” said astronomer Karen Meech.
It has long been theorized that such objects exist – asteroids or comets moving around between the stars and occasionally passing through our solar system – but this is the first such one we have seen.