Watery Mars: NASA Confirms Seasonal Presence of Surface Water on Mars

Summary: A watery Mars emerges as NASA confirms the seasonal presence of surface water, according to NASA's Sept. 28 press release.

Dark, football-field length streaks, known as recurring slope lineae (RSL), at Hale Crater, Mars: NASA/JPL-Caltech/Univ. of Arizona, via NASA

The National Aeronautics and Space Administration announced Monday, Sept. 28, 2015, at 11:30 a.m. Eastern Daylight Time on NASA TV that a four-year scrutiny of the Red Planet has yielded key evidence of the chemical identity of dark streaks occurring as seasonal events on Mars.

Wavelength analysis has identified perchlorate salts as ubiquitous in recurring slope lineae (RSL) occurring on steep sites on Mars.

RSL were discovered in 2011 via images captured by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter (MRO). The multipurpose spacecraft has been conducting exploration and reconnaissance missions since attaining its final science orbit of Mars in November 2006.

Recurring slope lineae appear at different latitudes and times as seasonal dark streaks on steep slopes. RSL present an annual, temperature-dependent cycle of emergence in spring and peak growth in downslope directions in summer, with fading and disappearance during the cold season. The surface temperatures conducive to the dark streak flows range from 250 to 300 Kelvin (minus 23 degrees to 27 degrees Celsius; minus 10 degrees to 81 degrees Fahrenheit).

Included among MRO's host of onboard scientific apparatuses is Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), an infrared-visible light spectrometer that searches for chemical and mineralogical evidence of past and present water on Mars. CRISM breaks sunlight reflected from Mars’ surface into a measurable spectrum of 544 colors. As a reflectance spectrometer, CRISM builds a profile of surface composition by measuring amounts of reflected light at different wavelengths to identify absorption signatures of specific chemicals and minerals.

A scientific team led by Lujendra Ojha, Ph.D. candidate in Georgia Institute of Technology's School of Earth and Atmospheric Sciences, analyzed CRISM wavelength data from four RSL locations. Coprates Chasma is located in the central portion of the equatorial Valles Marineris canyon system complex. Hale Crater lies in the southern highlands. Horowitz Crater is sited at 32 degrees south latitude. Palikir Crateris found inside Newton Crater in southern hemisphere's massively cratered Terra Sirenum.

CRISM's sweep of the four RSL locations detected wavelengths that absorption analysis associates with perchlorates. Perchlorates are salts which dissolve readily in water.

Lujendra Ojha's team identified the hydrated salts at all four locations as magnesium chlorate, magnesium perchlorate and sodium perchlorate.

NASA astrophysicist Tom Greene has shared that seemingly dry, arid Mars anciently welcomed a huge ocean, with a depth of at least 1 mile and a spread equal to two-thirds of Earth's Northern Hemisphere. But Mars seemingly lost its surface water because of an enigmatic climate change.

The dramatic confirmation of seasonal flows of briny water via NASA TV and the publication of Lujendra Ojha's findings, both presented Monday, Sept. 28, 2015, increase Mars' mystique and enliven the dialogue and research on deciphering mysteries of life on Earth and life's possibilities elsewhere.

Dark narrow streaks, called "recurring slope lineae," with a hypothesized formation from briny liquid water flow, emanate from the walls of Garni Crater on Mars; view constructed from observations taken March 12, 2013, by NASA's Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera: NASA/JPL-Caltech/Univ. of Arizona, via NASA

Acknowledgment

My special thanks to talented artists and photographers/concerned organizations who make their fine images available on the internet.

Image credits:

Recurring slope lineae (RSL) at Hale Crater, Mars: NASA/JPL-Caltech/Univ. of Arizona, via NASA @ http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA19916

Dark narrow streaks, called "recurring slope lineae," with a hypothesized formation from briny liquid water flow, emanate from the walls of Garni Crater on Mars; view constructed from observations taken March 12, 2013, by NASA's Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment (HiRISE) camera: NASA/JPL-Caltech/Univ. of Arizona, via NASA @ http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA19916

For further information:

Brown, Dwayne; Laurie Cantillo; Guy Webster. "NASA Confirms Evidence That Liquid Water Flows on Today's Mars." NASA > Press Release > MRO. Sept. 28, 2015.
Available @ https://www.nasa.gov/press-release/nasa-confirms-evidence-that-liquid-water-flows-on-today-s-mars

JPLraw. "Animation of Site of Seasonal Flows in Hale Crater, Mars." YouTube. Sept. 28, 2015.
Available @ https://www.youtube.com/watch?v=MDb3UZPoTpc&feature=youtu.be

Ojha, Lujendra, Mary Beth Wilhelm, Scott L. Murchie, Alfred S. McEwen, James J. Wray, Jennifer Hanley, Marion Massé, and Matt Chojnacki. “Spectral evidence for hydrated salts in recurring slope lineae on Mars.” Nature Geoscience > Letter. Published online Sept. 28, 2015.
Available via Nature Publishing Group @ http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2546.html