A tiny world at the edge of our solar system grew a mysterious atmosphere, and we don't know how

A very small body, far from the sun in an icy outer realm of the solar system, has mysteriously grown an atmosphere — and scientists are stumped as to how and why this happened. One possibility is that the atmosphere was produced through cryovolcanism, or basically ice volcanoes Another idea is the atmosphere could be related to an impact, but in that case, the impact must have happened relatively recently since such a thin atmosphere would leak into space and vanish within a thousand years. …