(IDEX Online) - Thousand of tonnes of diamonds are literally raining down on Saturn and Jupiter, say scientists.They believe frequent lightning strikes turn methane around the two planets into soot - carbon - which hardens as it falls and eventually becomes diamonds.Researchers Dr Kevin Baines, of the University of Wisconsin-Madison and Nasa's Jet Propulsion Laboratory, and Mona Delitsky, from California Speciality Engineering, analyzed temperature and pressure predictions for the planets' interiors.They also looked at how carbon behaves under different conditions, and concluded that stable crystals of diamonds will "hail down over a huge region" of Saturn in particular.Dr Baines said: "As the soot falls, the pressure on it increases. And after about 1,000 miles it turns to graphite - the sheet-like form of carbon you find in pencils."The bottom line is that 1,000 tonnes of diamonds a year are being created on Saturn."Actually getting hold of these diamonds from outer space is not so simple though. Jupiter is 498m miles from Earth and Saturn is 852m miles away.