SATURN MOON'S COLOSSAL METHANE SEAS:

Measurements of a big sea on Titan ... show that it contains about 9,000 cubic km of mostly liquid methane. This huge volume is equivalent, say scientists, to about 40 times the proven reserves of oil and gas on Earth.

"What you're talking about here is essentially liquefied natural gas," explained Randy Kirk from the US Geological Survey (USGS).

"People ask me if you could bring it to Earth, and that's a dumb idea on many levels. But what you might not realise is that there simply wouldn't be enough oxygen here to burn it all," he told BBC News.

So if we do manage to mine Titan (and eventually we will), we may be on the verge of an oxygen shortage. Environmentalists will be delighted.