Moons around Uranus may suddenly develop atmospheres in the spring

The moons of Uranus may have short-lived atmospheres every time the seasons change. The seasons there are so intense that these tenuous atmospheres, called exospheres, could exist briefly twice every Uranian year before freezing and falling back down to the surface.

Uranus’s poles are extremely tilted with respect to the planet’s orbit around the sun, which, along with its powerful magnetic field, makes the seasons there particularly extreme. Ben Teolis at the Southwest Research Institute in Texas and his colleagues used laboratory experiments on how carbon…