Prokaryotic life has dominated most of the evolutionary history of our planet, evolving to
occupy virtually all available environmental niches. Extremophiles, especially those thriving …

How and where did life on Earth originate? To date, various environments have been
proposed as plausible sites for the origin of life. However, discussions have focused on a …

The second ExoMars mission will be launched in 2020 to target an ancient location
interpreted to have strong potential for past habitability and for preserving physical and …

For over 100 years, endosymbiotic theories have figured in thoughts about the differences
between prokaryotic and eukaryotic cells. More than 20 different versions of endosymbiotic …

Geologic molecular hydrogen (H 2) occurs in the subsurface and vents and seeps at the
surface. However, this valuable natural resource is under-utilized in the economy because …

Over the last 30 years, geochemical research has demonstrated that abiotic methane (CH4),
formed by chemical reactions which do not directly involve organic matter, occurs on Earth in …

Earth's mantle convection, which facilitates planetary heat loss, is manifested at the surface
as present-day plate tectonics. When plate tectonics emerged and how it has evolved …

Over the last 70 years, prebiotic chemists have been very successful in synthesizing the
molecules of life, from amino acids to nucleotides. Yet there is strikingly little resemblance …

Hydrogen is a key energy source for subsurface microbial processes, particularly in
subsurface environments with limited alternative electron donors, and environments that are …

The conditions, timing, and setting for the origin of life on Earth and whether life exists
elsewhere in our solar system and beyond represent some of the most fundamental …