TNRTB Archive – Retained for reference information
A new discovery has refuted the astrobiologists’ mantra that “where there is methane there must be life.” A prevalent assumption in astrobiology research is that only living or once-living organisms can produce significant amounts of methane on small rocky bodies like Earth, Mars, or Europa (one of Jupiter’s moons). Thus, the discovery of a large amount of methane on a rocky planet or moon, according to this prevalent assumption, would be proof for the existence of life on such a body and evidence that life could arise naturally. A team of geochemists simulated the physical and chemical conditions of Earth’s upper mantle in a lab experiment. They demonstrated that when iron oxide, calcite, and water in the upper mantle are subjected to the pressure and temperature conditions known to exist in the upper mantle, methane is generated. Therefore, any body containing a mantle like Earth’s can be expected to produce methane independent of any past or present biology. Thus, the discovery of methane on a planet like Mars would not prove that life had existed there or that life can originate independent of miraculous intervention.
- Alexandra Goho, “Deep Squeeze: Experiments Point to Methane in Earth’s Mantle,” Science News 166 (2004), 198.
- Henry Scott et al., Proceedings of the National Academy of Sciences (2004), in press.
- Related Resource