In this artist's conception, a "hot Neptune" known as Kepler-36c looms in the sky of its neighbor, the rocky world Kepler-36b. The two planets have repeated close encounters, experiencing a conjunction every 97 days on average. At that time, they are separated by less than 5 Earth-Moon distances. Such close approaches stir up tremendous gravitational tides that squeeze and stretch both planets, which may promote active volcanism on Kepler-36b.
Credit: David A. Aguilar (CfA) High Resolution Image (jpg) Low Resolution Image (jpg)