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"Mars in Motion" (McEwan) - Coggle Diagram
"Mars in Motion" (McEwan)
Timeline
Gullies (Landforms that indicate presence of water) found by MGS
How? Martian atmosphere forbids liquid water
HiRISE (Better camera) finds more peculiar landscapes (CO2 Geysers, Spiders- radial networks of gas erosion)
McEwan's student finds the first of the peculiar black lines
Investigation confirms the existence of "Recurring Slope Linae" (RSL) that could hint at liquid water
RSL seasonal variance investigated in terms of Martian perihelion, deliquescence, water vapour upwelling and H2O reservoirs
Potential Evidence(s) of liquid water
RSL varies seasonally, this cannot be explained by dry deposition/dry erosion (rockfalls & landslides)
RSL peaks during the summer: cannot be explained by CO2-induced surface activity (unlike spiders and CO2 geysers)
Temperature during Martian perihelion is high enough for liquid BRINE (eutectic compositions of FeSO4 & Ca(ClO4)2) . This liquid brine can remain liquid till around -68 degrees Celcius
The ways to make ice: deliquescence, Water vapour upwelling, deep liquid H2O reservoirs
Analogous features in Antarctica (due to similar processes)
Methods
During summer, imaging data of the southern mid-latitude Martian slopes collected were compared pairwise to investigate gullies for topographical similarities.
Summer was chosen to control for influence of CO2 on surface activity, thus isolating for potential impacts of liquid water.
Discussion
These RSL indicate the influence of another factor besides CO2 that shapes the Martian landscape (hypothetically, liquid water).
However, this seasonal variation of RSL cannot be explained by dry processes (e.g. landslides/rockfalls) or by volatile compounds (water)