A new study suggests that ancient Mars experienced heavy precipitation, contradicting the long-held theory that it was always cold and dry. Geologists from the University of Colorado Boulder used computer simulations to explore how water may have shaped the surface of Mars billions of years ago.
The team, led by Amanda Steckel, found that precipitation from snow or rain likely formed the patterns of valleys and headwaters that still exist on Mars today. The researchers compared their simulations to actual data taken by NASA’s Mars Global Surveyor and Mars Odyssey spacecrafts, finding that the results aligned more closely with reality when including precipitation.
The study provides new insights into the history of another planet, our own Earth. With water present on ancient Mars, it’s possible that the erosion from flowing water stopped, leaving Mars with a frozen landscape similar to what we saw 3.5 billion years ago.
The research supports the theory that at least some water existed on the surface of Mars during the Noachian epoch, roughly 4.1 to 3.7 billion years ago. However, the exact mechanism behind the planet’s climate remains unclear. The study’s findings have significant implications for our understanding of Mars’ evolution and its potential habitability.
Source: https://www.colorado.edu/today/2025/04/21/did-it-rain-or-snow-ancient-mars-new-study-suggests-it-did