Deliquescence, liquid water, and the search for sources and sinks of methane on Mars

摘要

The recent discoveries of evidence for liquid saline water1'2'3'4 and methane5 on Mars have excited the science community by reviving the possibility of extant microbial life in this nearby planet. Here we report recently discovered photometric and spectral evidence that liquid saline water exists on Mars4. We show that this finding indicates that deliquescence occurs seasonally on some areas of Mars' polar region4. These discoveries support the hypothesis that liquid saline water is ubiquitous in the shallow Martian subsurface. This has important implications for the search for extraterrestrial life because a diverse array of terrestrial microorganisms thrives in highly saline water or brines6'7. We conclude this article by describing in situ and remote sensing instruments for detecting brines in the Martian subsurface and studying their relationship with sources and sinks of trace gases.