Cassini spies tiny moon Epimetheus next to Saturn’s rings

Saturn is a lot of people’s favourite planet due to its resplendent rings. Some of those rings – made of house-sized chunks of ice – have recently been snapped by the Cassini space probe alongside the planet’s diminutive moon Epimetheus (just 113 kilometres across). Released today, but taken on December 5, 2014, Cassini was 2 million kilometres away when it took the image.

Cassini see Saturn's A and F rings, as well as moon Epimetheus. [credit: NASA/JPL-Caltech/Space Science Institute]
Cassini see Saturn’s A and F rings, as well as moon Epimetheus. [credit: NASA/JPL-Caltech/Space Science Institute]

Moons like Epimetheus help astronomers understand the rings. As Saturn’s moons pull on the them, they create ripples. The size of these waves acts as a way of measuring the rings’ mass. It seems the rings have a mass about the same as another of Saturn’s moons – Mimas. Whilst we don’t know for sure where the rings came from, our best guess is that a moon about the same size as Mimas was once torn to pieces by Saturn’s immense gravity.

Cassini has been in orbit around Saturn since 2004 and continues to deliver both exquisite images and data.