SCIENTISTS around the world are scratching their heads about 21,000 tons of methane spotted on Mars. The mysterious cloud, picked up by three Earth-bound telescopes for several months in 2003, was described in a study published in the online edition of the journal Science.
The discovery came as a surprise because methane has never been detected on that planet. Because the gas is usually a byproduct of animal digestion and decaying plants and animals, there is much speculation as to the origin of the cloud.
Though tempting, no one is suggesting that cows, the source of much of the gas on Earth, are responsible for Martian methane. Those who lean toward the theory that Mars is inhabited suspect microbial life just beneath the planet's surface of being
Other scientists think the explanation is far more mundane: geologic changes on Mars. It is an intriguing argument that is bound to force scientists to consider new ways of detecting life on our planetary neighbor. Space agencies may have to start aiming probes straight toward the gas and where it is likely to have originated.
Because the cloud disappeared as mysteriously as it arrived, those who believe it is the by-product of microbial life also assume the cloud may have been "eaten" by other creatures that consider methane m-m-m-good.
All of this raises a tricky question: Do we really want to make contact with alien life that considers methane the cosmic equivalent of a Happy Meal?