{"275261":{"#nid":"275261","#data":{"type":"news","title":"Flowing Water on Mars Appears Likely But Hard to Prove","body":[{"value":"\u003Cp\u003EMartian experts have known since 2011 that mysterious, possibly water-related streaks appear and disappear on the planet\u2019s surface. Georgia Institute of Technology Ph.D. candidate Lujendra Ojha discovered them while an undergraduate at the University of Arizona. These features were given the descriptive name of recurring slope lineae (RSL) because of their shape, annual reappearance and occurrence generally on steep slopes such as crater walls. Ojha has been taking a closer look at this phenomenon, \u003Ca href=\u0022http:\/\/hirise.lpl.arizona.edu\/sim\/2013-12-10\/gifs\/3046-147_DTMa_1.gif\u0022\u003Esearching for minerals that RSL might leave in their wake\u003C\/a\u003E, to try to understand the nature of these features: water-related or not?\u003C\/p\u003E\u003Cp\u003EOjha and Georgia Tech Assistant Professor James Wray looked at \u003Ca href=\u0022http:\/\/hirise.lpl.arizona.edu\/sim\/2013-12-10\/gifs\/E-Coprates-25441-31019_1650_IRB-crop1_Labeled.gif\u0022\u003E13 confirmed RSL sites \u003C\/a\u003Eusing Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) images. They didn\u2019t find any spectral signature tied to water or salts. But they did find distinct and consistent spectral signatures of ferric and ferrous minerals at most of the sites. The minerals were more abundant or featured distinct grain sizes in RSL-related materials as compared to non-RSL slopes.\u003C\/p\u003E\u003Cp\u003E\u201cWe still don\u2019t have a smoking gun for existence of water in RSL, although we\u2019re not sure how this process would take place without water,\u201d said Ojha. \u201cJust like the RSL themselves, the strength of the spectral signatures varies according to the seasons. The signatures are stronger when it\u2019s warmer and less significant when it\u2019s colder.\u201d\u003C\/p\u003E\u003Cp\u003EThe research team also notes that the lack of water-related absorptions rules out hydrated salts as a spectrally dominant phase on RSL slopes. For example, ferric sulfates have been found elsewhere on Mars and are a potent antifreeze. If such salts are present in RSL, then they must be dehydrated considerably under exposure to the planet\u2019s conditions by the time CRISM observes them in the mid-afternoon.\u003C\/p\u003E\u003Cp\u003EThe findings were recently \u003Ca href=\u0022http:\/\/wray.eas.gatech.edu\/Ojha_etal2013-acceptedGRL.pdf\u0022\u003Epublished in Geophysical Research Letters\u003C\/a\u003E, and the Georgia Tech duo\u2019s newest paper, \u003Ca href=\u0022http:\/\/wray.eas.gatech.edu\/Ojha_etal2014-acceptedIcarus.pdf\u0022\u003Epublished in the journal Icarus\u003C\/a\u003E, indicates that predicting where RSL will appear is, at best, a guessing game.\u003C\/p\u003E\u003Cp\u003EOjha, Wray, and several Arizona-based colleagues looked at every image gathered by the High Resolution Imaging Science Experiment (HiRISE) from March to October of 2011. They hunted for areas that were ideal locations for RSL formation: areas near the southern mid-latitudes on rocky cliffs. They found 200, but barely any of them had RSL.\u003C\/p\u003E\u003Cp\u003E\u201cOnly 13 of the 200 locations had confirmed RSL,\u201d said Ojha. \u201cThere were significant differences in abundance and size between sites, indicating that additional unknown factors such as availability of water or salts may play a crucial role in RSL formation.\u201d\u003C\/p\u003E\u003Cp\u003EComparing their new observations with images taken in previous years, the team also found that RSL are much more abundant some years than others. Water on Mars today seems elusive at best \u2013 there one year, gone the next.\u003C\/p\u003E\u003Cp\u003E\u201cNASA likes to \u2018follow the water\u2019 in exploring the red planet, so we\u2019d like to know in advance when and where it will appear,\u201d Wray said. \u201cRSL have rekindled our hope of accessing modern water, but forecasting wet conditions remains a challenge.\u201d\u003C\/p\u003E\u003Cp\u003EOjha and Wray are also among several co-authors on another \u003Ca href=\u0022mailto:http:\/\/www.nature.com\/ngeo\/journal\/v7\/n1\/full\/ngeo2014.html\u0022\u003ERSL-related paper published this month in Nature Geoscience\u003C\/a\u003E. That study, led by the University of Arizona\u2019s Alfred McEwen, found some RSL in Valles Marineris, near the Martian equator.\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":[{"value":"Studies examine puzzling summertime streaks"}],"field_summary":"","field_summary_sentence":[{"value":"Two studies from College of Sciences explore possible \u0022water streaks\u0022 on Mars."}],"uid":"27560","created_gmt":"2014-02-10 13:19:03","changed_gmt":"2016-10-08 03:15:51","author":"Jason Maderer","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2014-02-10T00:00:00-05:00","iso_date":"2014-02-10T00:00:00-05:00","tz":"America\/New_York"},"extras":[],"hg_media":{"274261":{"id":"274261","type":"image","title":"RSL 1","body":null,"created":"1449244112","gmt_created":"2015-12-04 15:48:32","changed":"1475894964","gmt_changed":"2016-10-08 02:49:24","alt":"RSL 1","file":{"fid":"198718","name":"fig.-3c.jpg","image_path":"\/sites\/default\/files\/images\/fig.-3c_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/fig.-3c_0.jpg","mime":"image\/jpeg","size":7876666,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/fig.-3c_0.jpg?itok=xZiZ5TrF"}},"274271":{"id":"274271","type":"image","title":"RSL 2","body":null,"created":"1449244112","gmt_created":"2015-12-04 15:48:32","changed":"1475894964","gmt_changed":"2016-10-08 02:49:24","alt":"RSL 2","file":{"fid":"198719","name":"fig1a.jpg","image_path":"\/sites\/default\/files\/images\/fig1a_0.jpg","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/fig1a_0.jpg","mime":"image\/jpeg","size":1422006,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/fig1a_0.jpg?itok=ji19n2HO"}}},"media_ids":["274261","274271"],"related_links":[{"url":"http:\/\/www.cos.gatech.edu\/","title":"College of Sciences"},{"url":"http:\/\/wray.eas.gatech.edu\/Ojha_etal2013-acceptedGRL.pdf","title":"GRL Study"},{"url":"http:\/\/wray.eas.gatech.edu\/Ojha_etal2014-acceptedIcarus.pdf","title":"Icarus Study"}],"groups":[{"id":"1183","name":"Home"}],"categories":[{"id":"136","name":"Aerospace"}],"keywords":[{"id":"1325","name":"aerospace"},{"id":"4896","name":"College of Sciences"},{"id":"89371","name":"CSTAR"},{"id":"52181","name":"James Wray"},{"id":"7057","name":"Mars"},{"id":"788","name":"Water"}],"core_research_areas":[{"id":"39541","name":"Systems"}],"news_room_topics":[{"id":"71881","name":"Science and Technology"}],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJason Maderer\u003Cbr \/\u003EMedia Relations\u003Cbr \/\u003E\u003Ca href=\u0022mailto:maderer@gatech.edu\u0022\u003Emaderer@gatech.edu\u003C\/a\u003E\u003Cbr \/\u003E404-385-2966\u003C\/p\u003E","format":"limited_html"}],"email":["maderer@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}