Professor Tim Leighton, of Southampton University, recorded a waterfall in Hampshire and worked out the soundwaves the equivalent would make on the moon Titan, given the prevailing conditions:

The general temperatures on the surface are likely to be around minus 180C, with pools of liquid methane - and possibly rivers and seas of it too. And the 'air' is nitrogen.

A fall of water would obviously be frozen solid, but a methanefall is quite another matter.

A probe is due to land on Titan mid-January, 2005.

Professor Leighton embarked on the research after seeing an artist's impression of a waterfall on Titan, by recording an Earthly waterfall and processing the soundwaves to adjust for how they'd behave in Titan's conditions.