Science Seminars

2/19/2015 – Did Mars ever have a lively underground scene? New perspectives on the habitability of subsurface environments on Mars and beyond

Speaker: Joe Michalski (PSI)
Date: Wednesday, Feb 19, 2020
Time: 4:00 PM
Location: SPSC W120

Seminar Abstract:

By the time eukaryotic life or photosynthesis evolved on Earth, the Martian surface had become extremely inhospitable – cold, hyperarid, acidic, oxidizing and bathed in UV radiation. But, the subsurface of Mars could potentially have contained a vast microbial biosphere. Data from recent missions have revealed spectacular views of materials exhumed from the subsurface by impact craters. Those data show that all the necessary ingredients for life existed at depth on Mars, some of which include carbon for biomass, fluids as solvents, nutrients for growth and sustenance, and a favorable thermal regime. Exhumed terrains contain carbonates, complex, mixed-layer (typically Fe-rich) clays of probable hydrothermal origins, and juxtaposed primary minerals, suggesting that chemical gradients were present. In this talk, I evaluate new evidence suggesting that the subsurface is, and has likely always been, the most habitable part of Mars. I will also discuss why the notion of a “habitable zone” around our Sun or other stars might need to be reconsidered, given the possibility that deep biospheres are potentially common in the galaxy.