By 
June 30th, 2023
Active gullies and gully stratigraphy on Mars. Image credit: University of Arizona’s High Resolution Imaging Science Experiment (HiRISE)/Dickson, et al.
A new study spotlights how gullies on the slopes of craters on Mars could have formed by on-and-off periods of meltwater from ice on and beneath the planet’s surface.
The results from the new study suggest that gully formation was driven by periods of melting ice and by carbon dioxide (CO2) frost evaporation in other parts of the year.
Additionally, the researchers report that this has likely occurred repeatedly over the past several million years on Mars with the most recent occurrence about 630,000 years ago.
Turn up the volume
“Our study shows that the global distribution of gullies is better explained by liquid water over the last million years,” said Jay Dickson, the study’s lead author and a former researcher at Brown University and now at California Institute of Technology.
Uppermost vertical extent of gullies on Mars.
Image credit: Mars Reconnaissance Orbiter Context Camera (CTX) global panchromatic mosaic overlain by MOLA topography of the Thaumasia highlands/
Dickson, et al.
“Water explains the elevation distribution of gullies in ways that CO2 cannot,” Dickson noted in a Brown University press statement. “This means that Mars has been able to create liquid water in enough volume to erode channels within the last million years, which is very recent on the scale of Mars geologic history.”
Bridge between warm and wet
The paper, published in Science magazine, raises anew the fundamental question of whether life could exist on Mars.
This is because life, as it’s known on Earth, goes hand in hand with the presence of liquid water. Mars will eventually tilt to 35 degrees again, the researchers said.
“Could there be a bridge, if you will, between the early warm and wet Mars and the Mars that we see today in terms of liquid water?” said James Head, a professor of geological sciences at Brown and a study co-author.
Life on ice
“Everybody’s always looking for environments that could be conducive to not just the formation of life but the preservation and continuation of it,” Head noted in the Brown University statement.
Image credit: NASA
“Any microorganism that might have evolved in early Mars is going to be in places where they can be comfortable in ice and then also comfortable or prosperous in liquid water. In the frigid Antarctic environment, for example, the few organisms that exist often occur in stasis, waiting for water,” Head added.
This research underscores the importance of these gullies in terms of potential targets to visit by robotic or human means during future exploration missions on Mars.
Go to – “Gullies on Mars could have formed by melting of water ice during periods of high obliquity” — at:
https://www.science.org/doi/10.1126/science.abk2464
Also go to this video, A time-lapse of gullies forming in the Upper Wright Valley of the Antarctic Dry Valleys. Video courtesy of Jim Head, Brown University at:
Posted in Space News
