Water once flowed on ‘cold and icy’ ancient Mars, claims study
Water may have flowed on ancient Mars in peak summers, even though the red planet was generally frozen over, a study suggests. For scientists trying to understand what ancient Mars might have been like, the red planet sends some mixed signals. While water-carved valleys and lakebeds leave little doubt that water once flowed on the surface, climate models for early Mars suggest average temperatures around the globe stayed well below freezing.
The study led by scientists at Brown University in the US offers a potential bridge between the “warm and wet” story told by Martian geology and the “cold and icy” past suggested by atmospheric models.
The study, published in the journal Icarus, shows that it is plausible, even if Mars was generally frozen over, that peak daily temperatures in summer might sneak above freezing just enough to cause melting at the edges of glaciers.
That meltwater, produced in relatively small amounts year after year, could have been enough to carve the features observed on the planet today, the researchers conclude. “We see this in the Antarctic Dry Valleys, where seasonal temperature variation is sufficient to form and sustain lakes even though mean annual temperature is well below freezing,” said Ashley Palumbo, PhD …read more