The first definitive detection of methane in the atmosphere of Mars indicates that it still has geologic activity powered by heat from its interior. A team of NASA and university scientists used spectrometer instruments attached to several telescopes to detect plumes of methane that were emitted from specific sites during Mars' warmer seasons of spring and summer. It is possible that the detected methane was either produced by geologic processes such as the oxidation of iron (serpentinization) or by microscopic Martian life below the planet's surface. The methane released today could be produced currently, or it could be ancient methane trapped in ice 'cages' called clathrates or as gas below a sub-surface ice layer.