係堅野
http://www.nasa.gov/mission_pages/mars/news/marsmethane.html
但係只係話搵到methane
"However, it is possible a geologic process produced the Martian methane, either now or eons ago. "
"It will take future missions, like NASA's Mars Science Laboratory, todiscover the origin of the Martian methane. One way to tell if life isthe source of the gas is by measuring isotope ratios. Isotopes areheavier versions of an element; for example, deuterium is a heavierversion of hydrogen. In molecules that contain hydrogen, like water andmethane, the rare deuterium occasionally replaces a hydrogen atom.Since life prefers to use the lighter isotopes, if the methane has lessdeuterium than the water released with it on Mars, it's a sign thatlife is producing the methane."
