Hm. Schaut aus, als wäre unsere beste Chance auf ein Tref­fen mit den klei­nen grü­nen Männ­chen auf dem zweitbes­ten Kan­di­da­ten: Titan.

Some­thing strange is afoot in the atmo­s­phere of Saturn’s moon Titan, accor­ding to data sent back from the Cas­sini mis­sion. Data retur­ned from a spec­tro­me­ter on Cas­sini indi­ca­tes that there’s a large flux of hydro­gen in the moon’s atmo­s­phere, with the gas for­ming in the upper atmo­s­phere and being remo­ved from the atmo­s­phere at Titan’s sur­face. We don’t cur­rently know what pro­cess is ensu­ring its remo­val, but the amounts of hydro­gen being taken out of the atmo­s­phere are con­sis­tent with an ear­lier pro­po­sal of methane-based life.

Titan’s atmo­s­phere is rich in hydro­car­bon com­pounds, and che­mi­cal chan­ges in the upper atmo­s­phere are dri­ven by the arri­val of ultra­vio­let light from the sun. One of the expec­ted results of the UV expo­sure is the libe­ra­tion of mole­cu­lar hydro­gen from methane via a pro­cess that pro­du­ces more com­plex hydro­car­bons. With little oxy­gen to react with, the mole­cu­lar hydro­gen should remain sta­ble. Some of it will escape into space, but a new paper indi­ca­tes that a sub­stan­tial amount of that hydro­gen migra­tes down through the atmo­s­phere towards Titan’s surface.

Wei­ter­le­sen bei Ars Technica.