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EnceladusEnceladus Enceladus, one of Saturn’s moons, is a bright, silvery-white ball measuring only 498 kilometres (309 miles) across. Like a mirror, the surface of Enceladus reflects nearly all the light that reaches it. Part of its surface has craters but most other parts are smooth. The long grooves on Enceladus’s surface, some of them fringed by distinctive mint-green stripes, are thought to be faults (cracks) in the moon’s icy crust, possibly indicating the existence of a liquid layer lying beneath.

Ice volcanoes on EnceladusIce volcanoes on Enceladus

Eruptions of ice

There are craters and ridges in Enceladus's northern hemisphere, but its southern polar region is smooth. Astronomers think that Enceladus may be almost entirely coated by water ice. The ice has melted only recently, wiping out any craters from past meteorite bombardment. The surface is probably being regularly recoated by eruptions of ice bursting through cracks in the moon’s thin crust.

Snaking across this smooth region are four long grooves, each fringed by a mint-green stripe. From these so-called “tiger stripes”, ice "volcanoes" erupt fountains of water vapour and tiny hailstones 500 kilometres (300 miles) into space. The ice particles ejected by these volcanoes may also contribute to Saturn’s ring system.

Stripes and grooves on the surface of EnceladusStripes and grooves on the surface of Enceladus
Faults, wrinkles and Faults, wrinkles and "soft" craters on Enceladus

existence of life

Enceladus was discovered by German-born British astronomer William Herschel, the discoverer of Uranus, in 1789. The find was made while he was using his new 1.2-metre telescope.

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