Talk:Seasonal flows on warm Martian slopes

Alternative hypotheses?

Are there any alternative hypotheses for the streaks proposed in the scientific literature? 68.195.118.202 (talk) 22:29, 5 August 2011 (UTC)

Yes, this evidence is falsifiable, which by its nature ensures an alternative will appear. But it seems like this is very very new evidence, and will have to be confirmed many times over before we are certain. Considering that, it will likey be about a fair bit longer until an actual critique can be meaningful; cant work on a counter-hypothesis if the hypothesis hasnt been fully examined after all. So, yeah, as soon as such information becomes available we'll definetly put it up, but that could be quite some time. or tomorrow. hard to say really. Science is weird like that.

74.132.249.206 (talk) 02:13, 6 August 2011 (UTC)

Between the strong relationship between dust availability, convection cells, and RSL activity following the Martian Year 34's planet-encircling dust event, and the lack of spectral evidence of liquids associated with RSL, it seems that the community is coming around to the idea that RSL are dry granular flows. 75.69.98.99 (talk) 00:02, 20 September 2023 (UTC)

Merger proposal

The following discussion is closed. Please do not modify it. Subsequent comments should be made in a new section. A summary of the conclusions reached follows.

The result of this discussion was to not merge. BatteryIncluded (talk) 14:21, 14 July 2013 (UTC)

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I propose that Martian Gullies be merged into Seasonal flows on warm Martian slopes. The reason is that the material is duplicated. One difference is that the Martian Gullies article assumes the gullies are formed by brine, while the Seasonal flows on warm Martian slopes article seems neutral and mentions other hypotheses on their cause. Cheers, BatteryIncluded (talk) 17:00, 11 July 2013 (UTC)

Strong oppose. These are fundamentally different things. People have speculated that seasonal flows could carve gullies, but this remains relatively open. "Seasonal flows" specifically refers to the dark streaky linear patterning that can be seen seasonally below headwalls in certain, thus far restricted locations on Mars. "Gullies" are the densely branched, hourglass shaped structures which are widespread in the midlats. Changes are seen in gullies, but no-one has ever seen what you could argue is seasonal (year-cyclic) change. The arguments over gully formation are still ongoing, and I'm convinced we shouldn't convolve the two. That said, the gully article needs a cleanup (I'll try the weekend) and I've not read the seasonal flows article in detail, but I daresay it's probably also not 100% clear on this distinction. DanHobley (talk) 17:35, 11 July 2013 (UTC)

Strong oppose Seasonal flows are not Gullies, simple as that. Different phenomena. Robert Walker (talk) 21:39, 11 July 2013 (UTC)

Oppose - FWIW - my thinking at the moment => seems the "Martian Gullies" article is about physical characteristics of Mars whereas the "Seasonal flows on warm Martian slopes" article is more about processes occuring on Mars instead - although the articles seem similar in some ways, maybe they're sufficiently different to remain separate? - and not merged - comments from others may be helpful with this of course - in any case - Enjoy! :) Drbogdan (talk) 17:52, 11 July 2013 (UTC)

In favor - Features & cause of the same subject: As Dan points out, the dark streaks and gullies are the features of flows. A similar merge antecedent that comes to mind are the Dark dune spots and Martian spiders features which were merged to Martian geysers, the alleged cause of said features. Cheers, BatteryIncluded (talk) 18:17, 11 July 2013 (UTC)

Comment 1 - I'm not familiar with any paper arguing gullies are seasonally active. Not even for a single site (do you have one, BI?). Carved by wet flows, yes, but not actual proof of seasonality. Even modern activity remains contentious, no? The true "seasonal flows" have documentation of wetting in summer, fading in winter. Gullies don't. Comment 2 - Not all gullies result from seasonal flows, and moreover, and more importantly, not all seasonal flows are gullies. With the spiders, all spiders are formed by geysers, and this hypothesis is well accepted by the community. Just food for thought. DanHobley (talk) 01:05, 12 July 2013 (UTC)

Further comment (I'm full of them today, apparently?) - IMO, the thing that actually does map one-to-one onto the features discussed in that seasonal flows article are Recurring Slope Lineae, as described at Dark_slope_streak#Recurring_slope_lineae_(warm-season_flows). If you are really set on some merging, the seasonal flows article should be renamed "Recurring slope lineae". That's what it's about, not gullies! I note the explicit sentence in the flows article: "Also, while gullies are abundant on cold, pole-facing slopes, these dark flows are on warmer, equator-facing slopes." DanHobley (talk) 01:15, 12 July 2013 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

News from NASA

December 10, news from NASA: "NASA Mars Spacecraft Reveals a More Dynamic Red Planet" "Seasonal Changes in Dark Marks on an Equatorial Martian Slope" http://www.jpl.nasa.gov/news/news.php?release=2013-361&1 -cHEERS, BatteryIncluded (talk) 22:16, 17 December 2013 (UTC)

FWIW - News seems *very* interesting imo - if not aware, related ref was added to article several days ago => < ref name="NASA-20131210">Webster, Guy; Brown, Dwayne (December 10, 2013). "NASA Mars Spacecraft Reveals a More Dynamic Red Planet". NASA. Retrieved December 10, 2013.</ref> - thanks for reminding me - may have to take a closer look at first opportunity - Enjoy! :) Drbogdan (talk) 00:38, 18 December 2013 (UTC)

References

Missing the obvious: It's algae

The dark stuff is algae. It brightens when the temperature gets colder because the water in the algae cells freeze and turn white like water ice normally does. It's not unusual for algae to be darkly colored, but obviously (once again) being dark helps the algae absorb sunlight to warm up and melt the water ice in its cells. Maybe there are bugs there feeding on the algae, kind of like Belgica antarctica. Badon (talk) 09:07, 11 October 2014 (UTC)

It is also obvious that Elvis shot JFK. :-) BatteryIncluded (talk) 15:18, 11 October 2014 (UTC)

NASA-TV/ustream (9/28/2015@11:30am/et/usa) - Mars Mystery Solved.

NASA-TV/ustream (Monday, 28 September 2015@11:30am/et/usa) - NASA will detail a "Major Science Finding" about the planet Mars - Enjoy! :) Drbogdan (talk) 01:12, 25 September 2015 (UTC)

BRIEF Followup - evidence presented that liquid water may be currently flowing on the planet Mars (conference videos and somewhat related Nature (journal) (1979) reference re lifeforms in the hypersaline (and/or brine) water of Don Juan Pond, Antarctica) - in any case - Enjoy! :) Drbogdan (talk) 18:08, 28 September 2015 (UTC)

References

Section on habitability

It's extraordinary that this article doesn't mention the potential habitability of the RSL's. That's the main point of interest in them.

Suggested section:

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For an assessment of their habitability see [1]

• "Finding 4-1: 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 $a_{w}$ [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"

Since then we have had confirmation that the features involve seasonally hydrated salts, and the evidence also suggests fairly substantial amounts of water, at least for microbes. At the end of the press conference, the researchers gave a rough estimate of a total annual flow of at least 100,000 tons for the entire Valles Marineres region. In this calculation they assumed only 5% water in the solution and a film with a thickness of 10 mm which is about what you need for the material to flow at all [2]. They are amongst the most favoured candidate sites for present day life on Mars. Whether they are habitable or not will depend on the temperature of the water and its salinity.

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I suggest inserting what I have just written as a new section in the article. If there are no comments I will insert it in a few days time. Robert Walker (talk) 12:52, 4 February 2017 (UTC)

History

There should be some reference to when recurring slope lineae were first identified, and when they were first associated with water.Royalcourtier (talk) 09:17, 30 September 2015 (UTC)

Right, I'll do that when I edit the article. Or feel free to add it yourself. They were first reported was in the paper by McEwan in Science, August 5, 2011. [3]. Already suspected as involving flowing brines back then. Finally proven pretty much conclusively to involve liquid water in some form, possibly habitable if temperatures and salinity are right - after detection of hydrated salts that change their hydration state rapidly, reported in a paper published on 28th September 2015 along with a press conference [4] Robert Walker (talk) 12:58, 4 February 2017 (UTC)

They were actually first spotted in 2010, though the discovery was not published until 2011, and were a remarkable discovery by the then undergraduate Nepalese American student Lujendra Ojha. Robert Walker (talk) 14:38, 4 February 2017 (UTC)

RSL not seen where water is present

A cross-section of underground water ice is exposed at the steep slope that appears bright blue in this enhanced-color view from the MRO. The scene is about 500 meters wide. The scarp drops about 128 meters from the level ground

I think it is worth noting that even where water is confirmed to be present at these 8 reported slopes, RSL were not seen. I'll keep my eyes open for papers on that, as this article may need to be focused even further on dry flow hypotheses. BatteryIncluded (talk) 17:02, 13 January 2018 (UTC)

References