Astronomers believe they have discovered the first known moon beyond our solar system, in orbit around a gigantic planet 8,000 light years away. “The first exomoon is obviously an extraordinary claim and it requires extraordinary evidence,” said David Kipping, an astronomer at Columbia University in New York who has spent more than a decade hunting for far-flung moons. The moon’s Neptune size was on a scale that had “hardly been anticipated” and “defies easy explanation” based on current theories of moon formation.
