Detection of methane in the martian atmosphere: evidence for life?
Publication date: 15 December 2004
Authors: Krasnopolsky, V.A. et al.
Copyright: Elsevier Inc.
Using the Fourier Transform Spectrometer at the Canada France Hawaii Telescope, we observed a spectrum of Mars at the P-branch of the strongest CH4 band at 3.3 Œm with resolving power of 180,000 for the apodized spectrum. Summing up the spectral intervals at the expected positions of the 15 strongest Doppler-shifted martian lines, we detected the absorption by martian methane at a 3.7 sigma level which is exactly centered in the summed spectrum. The observed CH4 mixing ratio is 10+/-3 ppb. Total photochemical loss of CH4 in the martian atmosphere is equal to 2.2x10 cms, the CH4 lifetime is 340 years and methane should be uniformly mixed in the atmosphere. Heterogeneous loss of atmospheric methane is probably negligible, while the sink of CH4 during its diffusion through the regolith may be significant. There are no processes of CH4 formation in the atmosphere, so the photochemical loss must therefore be balanced by abiogenic and biogenic sources. - Remainder of abstract truncated -Link to publication