Could Mars Host Life? Tiny Brines Appear Twice Daily

A 20-Year Question
Could Mars still host liquid water? A new University of Arkansas study says yes — but only in tiny, salty bursts.

Liquid water is key for life. On Mars, salts can lower the freezing point, creating brines that could exist despite the cold and dryness.

Data from NASA’s Viking 2 lander, which saw frost on Mars in 1976, offered the best evidence to explore brine formation.

In late winter and early spring, frost in certain regions can briefly melt, forming salty brines before quickly vanishing.

Modeling shows conditions are perfect two times a day — early morning and late afternoon — for about one Martian month each year.

This salt can stay liquid at -75°C. Mars’ temperatures in some spots match that “sweet spot” twice daily during the season.

The water volume would be tiny — not enough for people — but could have sustained hardy microbial life in the past.

Knowing when and where brines might form could help future Mars missions search for signs of life at the right moments.

Researchers suggest landers with moisture and chemical sensors target these seasonal windows to directly confirm brines.

University of Arkansas — Research published in Nature Communications Earth & Environment, August 13, 2025.