Scientists say that warm ice can explain some of the odd features of one of Saturn's moons, Enceladus.

Scientists have been puzzled for some time about why the south polar surface of Enceladus has such a strong flow of heat. The surface in the region also seems much younger than the rest of the moon.

Experts at NASA say that pictures from their Cassini spacecraft caught Enceladus "in the middle of a burp". This is when bubbles of warmer, light ice rise to the moon's surface, like in a lava lamp. This would send colder, heavier ice down below and alter the surface of Enceladus.

Picture by NASA/JPL/Space Science Institute