Cassini finds two tiny Saturnian moons

Blink and you'll miss 'em

Scientists monitoring data from the Cassini-Huygens mission have discovered two new moons in orbit around Saturn, bringing the planet's total moon collection to 33.

The two bodies are very small: one is around three kilometres across and the other only measures four kilometres. Until now, the smallest of Saturn's known moons was around 20km across.

For now, the moons have been named in standard nomenclature: S/2004 S1 and S/2004 S2. Very mythic, we're sure you'll agree. Astronomers involved in the discovery suspect that they've seen one of the moons before: it may be that S/2004 S1 was previously catalogued as S/1981 S14, during the Voyager mission 23 years ago.

According to the European Space Agency, researchers were surprised to find the moons where they are. They expected to find similar sized bodies in the gaps in the planet's rings, but S1 and S1 orbit between two other moons: Mimas and Enceladus.

Astronomers would have expected two small moons like these to have been broken up by collisions with bodies from further out in the solar system. So S1 and S2 may actually shed some light on the numbers of small comets in the outer solar system, and therefore on the cratering histories of the moons of giant planets. ®

Bootnote

There are pictures of the moons, but because they (the moons) are so small, it is almost impossible to pick the spots of light out from the background if we shrink the pictures to fit our page.

So instead of putting up a blurry image, we'll link to them here, where you can check them out in their full glory.

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