Possible present day habitats for life on Mars (Including potential Mars special regions): Difference between revisions
Possible present day habitats for life on Mars (Including potential Mars special regions) (edit)
Revision as of 19:16, 2 November 2019
, 4 years ago→Warm Seasonal flows (Recurrent Slope Lineae)
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* "Although no single model currently proposed for the origin of RSL adequately explains all observations, they are currently best interpreted as being due to the seepage of water at > 250 K, with <math>a_w</math> [water activity] unknown and perhaps variable. As such they meet the criteria for Uncertain Regions, to be treated as Special Regions. There are other features on Mars with characteristics similar to RSL, but their relationship to possible liquid water is much less likely"The "Special Regions" assessment says of them:<ref name="RummelBeaty2014"/>
: A study of RSLs in Eos Chasma shows that the features are consistent with dust cascades, since they terminate at slopes matching the stopping angle for granular flows of cohesionless dust, and they also ruled out formation of substantial quantities of crust‐forming evaporitic salt deposits, though the hydrated salts and seasonal nature continue to suggest some role for water in their formation (Dundas et al, 2017)<ref name=McEwan>McEwen, A.S., Ojha, L., Dundas, C.M., Mattson, S.S., Byrne, S., Wray, J.J., Cull, S.C., Murchie, S.L., Thomas, N. and Gulick, V.C., 2011. Seasonal flows on warm Martian slopes. Science, 333(6043), pp.740-743.</ref>.
: Difficulties with the dust explanation include the rapid fading away of the streaks at the end of the season, instead of the more usual decades, and a lack of an explanation of how the dust is resupplied year after year. Resupply also remains a major question for the models involving substantial amounts of liquid brines <ref name=Stillman>(Stillman quoted in David, L., 2017, Mars Flows: A Recurring Controversy, Leonard David's "Inside Outer Space" blog (space journalist)</ref>. A study of RSLs in the Valles Marineres finds that they seem to traverse bedrock rather than the regolith of other RSLs, and that if water is involved in their formation, then substantial amounts must be needed to sustain lengthening throughout the season <ref> Stillman, D.E., Michaels, T.I. and Grimm, R.E., 2017. Characteristics of the numerous and widespread recurring slope lineae (RSL) in Valles Marineris, Mars. Icarus, 285, pp.195-210.</ref>
<!-- this para is included from my own OSF preprint https://osf.io/kad38 - Robert Walker --->
==Sun warmed dust grains embedded in ice==
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