Brown: Water Could Have Flowed on 'Cold & Icy' Ancient Mars

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Brown: Water Could Have Flowed on 'Cold & Icy' Ancient Mars

Post by bystander » Tue Oct 17, 2017 3:01 pm

Study Shows How Water Could Have Flowed on 'Cold & Icy' Ancient Mars
Brown University | 2017 Oct 17

Research by planetary scientists at Brown University finds that periodic melting of ice sheets on a cold early Mars would have created enough water to carve the ancient valleys and lakebeds seen on the planet today.
[img3="Extensive valley networks spidering through the southern highlands of Mars
suggest that the planet was once warmer and wetter, but new research shows
that water could still have flowed intermittently on a cold and icy early Mars.
Credit: NASA/JPL-Caltech/ASU
"]https://news.brown.edu/files/styles/hor ... leys_0.jpg[/img3][hr][/hr]
For scientists trying to understand what ancient Mars might have been like, the red planet sends some mixed signals. Water-carved valleys and lakebeds leave little doubt that water once flowed on the surface. But climate models for early Mars suggest average temperatures around the globe stayed well below freezing.

A recent study led by Brown University geologists 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 shows that it’s 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. ...

The researchers started with a state-of-the-art climate model for Mars — one that assumes an ancient atmosphere composed largely of carbon dioxide (as it is today). The model generally produces a cold and icy early Mars, partly because the sun’s energy output is thought to have been much weaker early in solar system history. The researchers ran the model for a broad parameter space for variables that may have been important around 4 billion years ago when the iconic valley networks on the planet’s southern highlands were formed. ...

Late Noachian Icy Highlands climate model: Exploring the possibility of transient melting and fluvial/lacustrine
activity through peak annual and seasonal temperatures
- Ashley M. Palumbo, James W. Head, Robin D. Wordsworth
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