Original URL: http://www.theregister.co.uk/2005/07/13/cassini_makes_a_movie/

Cassini films Hyperion in orbit

The space opera continues

By Lucy Sherriff

Posted in Science, 13th July 2005 08:52 GMT

The latest snaps to come back from the Cassini mission are of Hyperion, one of the smaller of Saturn's many moons. The NASA spacecraft took a sequence of 25 images over around two-and-a-half days and built up a short movie of the moon as it tumbled along on its elliptical orbit.

The moon is an irregular shape, but is approximately 164 by 130 by 107 kilometres. This is close to the size limit where its own gravity would begin to crush any weak materials inside, making the moon gradually more spherical, but is not quite big enough for this to happen.

In fact, Hyperion is only 60 per cent as dense as ice, causing researchers to speculate that the moon has plenty of empty space in its interior. It also suggests that the body is mostly composed of water ice, with relatively little rock and metal.

It looks rocky on the outside, but that is probably dust left over from impacts of darker matter, the scientists suspect.

Cassini will fly past Hyperion again in September this year, when it will take a closer look at the little moon. Expect some more pictures then.

You can check out the movie, which was shot between 9 and 11 June, here. ®

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