Subscribe free to our newsletters via your
  Mars Exploration News  




Subscribe free to our newsletters via your




















MARSDAILY
Mars Canyons Study Adds Clues about Possible Water
by Staff Writers
Pasadena CA (JPL) Jul 12, 2016


Blue dots on this map indicate sites of recurring slope lineae (RSL) in part of the Valles Marineris canyon network on Mars. RSL are seasonal dark streaks that may be indicators of liquid water. The area mapped here has the highest density of known RSL on Mars. Image courtesy NASA/JPL-Caltech/Univ. of Arizona. For a larger version of this image please go here.

Puzzles persist about possible water at seasonally dark streaks on Martian slopes, according to a new study of thousands of such features in the Red Planet's largest canyon system. The study published investigated thousands of these warm-season features in the Valles Marineris region near Mars' equator.

Some of the sites displaying the seasonal flows are canyon ridges and isolated peaks, ground shapes that make it hard to explain the streaks as resulting from underground water directly reaching the surface. It is highly unlikely that shallow ground ice would be present as a source for seasonal melting, given the warm temperatures in the equatorial canyons. Water pulled from the atmosphere by salts, or mechanisms with no flowing water involved, remain possible explanations for the features at these sites.

What are RSL?
These features are called recurring slope lineae, or RSL, a mouthful chosen to describe them without implying how they form. Since their discovery in 2011, Martian RSL have become one of the hottest topics in planetary exploration, the strongest evidence for any liquid water on the surface of modern Mars, even if transient.

They appear as dark lines extending downslope during a warm season, then fading away during colder parts of the year, then repeating the progression in a following year. Water, in the form of hydrated salts, was confirmed at some RSL sites last year, including in Valles Marineris.

Research results published present many findings from detailed observation of 41 RSL sites in central and eastern portions of Valles Marineris, the largest canyon system in the solar system. Each site is defined as the size of a single image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter: about 3.4 miles by 8 miles (5.4 by 12 kilometers). The number of individual lineae (flows) in each site ranges from a few to more than 1,000.

Densest Population of RSL
"There are so many of them, it's hard to keep track," said Matthew Chojnacki of the University of Arizona's Lunar and Planetary Laboratory, Tucson, and lead author of today's report in the Journal of Geophysical Research: Planets.

"The occurrence of recurring slope lineae in these canyons is much more widespread than previously recognized. As far as we can tell, this is the densest population of them on the planet, so if they are indeed associated with contemporary aqueous activity, that makes this canyon system an even more interesting area than it is just from the spectacular geology alone."

The possibility of liquid water at or near the surface of Mars carries major ramifications for investigating whether life exists on Mars, since all known life relies on liquid water. Either liquid or frozen water near the surface could become an important resource for humans on Mars. Fresh crater impacts and other data have revealed water ice close to the surface at many locations in middle and high latitudes of Mars. If RSL are indicators of water, they extend possible water-access sites to low latitudes.

If water is involved in forming RSL, what is the mechanism? Seeking an answer, Chojnacki and five co-authors examined the geological context of canyonland RSL sites and also calculated how much water would need to be present if the streaks are due to liquid water seeping through a thin surface layer to darken the ground.

Many of the sites where RSL were previously identified are on inner walls of impact craters. At that type of site, a conceivable explanation could be that an extensive underground layer holding water was punctured by the crater-forming impact long ago and still feeds warm-season flows. No such underground layer fits the ridge or peak shapes at several of the RSL sites in the new study.

Salt Connection
Another possible mechanism previously proposed for RSL is that some types of salts so strongly pull water vapor out of the Martian atmosphere that liquid brine forms at the ground surface. The new study bolsters the link between RSL and salts. Some sites bear bright, persistent streaks near the dark, seasonal ones. The bright streaks might result from salt left behind after evaporation of brine.

"There are problems with the mechanism of pulling water from the atmosphere, too," Chojnacki said. If it is seeping water that darkens RSL, the amount of liquid water required each year to form the streaks in the studied portion of Valles Marineris would total about 10 to 40 Olympic-size swimming pools (about 30,000 to 100,000 cubic meters), the researchers estimate. The amount of water vapor in the atmosphere above the whole Valles Marineris region is larger than that, but researchers have not identified a process efficient enough at extracting water from the atmosphere to get that much onto the surface.

"There do seem to be more ways atmosphere and surface interact in the canyons than in blander topography, such as clouds trailing out of the canyons and low-lying haze in the canyons." he said. "Perhaps the atmosphere-surface interactions in this region are associated with the high abundance of recurring slope lineae. We can't rule that out, but a mechanism to make the connection is far from clear."

An RSL-forming mechanism with very limited flowing water may also be possible. Based on an Earth resident's experience, it's easy to see a resemblance to wet ground extending from seeping water, but Mars is foreign, even when it looks familiar. Water-free processes do produce other flow features on Mars. RSL's formation mechanism might be entirely dry, or perhaps a hybrid "damp" model requiring much less water than suggested by flowing-water mechanisms.

Three-Dimensional Changes
Another factor added by the new study is that RSL not only darken the surface, but are also associated with material moving downslope. The new study documents slumping and other three-dimensional changes at some RSL sites, occurring seasonally in tandem with the streaks.

Other studies of RSL, including laboratory experiments simulating them on Earth, are in progress. The report published offers this interim conclusion: "Collectively, results provide additional support for the notion that significant amounts of near-surface water can be found on Mars today and suggest that a widespread mechanism, possibly related to the atmosphere, is recharging RSL sources."

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace and Technologies Corp. of Boulder, Colorado. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter and collaborates with JPL to operate it.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

.


Related Links
Mars Reconnaissance Orbiter
Mars News and Information at MarsDaily.com
Lunar Dreams and more






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
MARSDAILY
Mars Canyons Study Adds Clues about Possible Water
Pasadena CA (JPL) Jul 11, 2016
Puzzles persist about possible water at seasonally dark streaks on Martian slopes, according to a new study of thousands of such features in the Red Planet's largest canyon system. The study published investigated thousands of these warm-season features in the Valles Marineris region near Mars' equator. Some of the sites displaying the seasonal flows are canyon ridges and isolated peaks, g ... read more


MARSDAILY
Russia to spend $60M in 2016-2018 to fund space voyages to Moon, Mars

Russian Moon Base to Hold Up to 12 People

US may approve private venture moon mission: report

Fifty Years of Moon Dust

MARSDAILY
Dutch Radio Antenna to Depart for Moon on Chinese Mission

Chinese Space Garbageman is not a Weapon

China to launch its largest carrier rocket later this year

China committed to peaceful use of outer space

MARSDAILY
New Crew Members, Including NASA Biologist, Launch to Space Station

Three astronauts blast off for ISS in upgraded Soyuz craft

Soyuz-FG to launch new crew to ISS fully assembled

Down to Earth: Returned astronaut relishes little things

MARSDAILY
New Horizons Receives Mission Extension to the Kuiper Belt

Alex Parker Discovers Moon Over Makemake in the Kuiper Belt

Hubble locates new dark spot on Neptune

Pluto's Subsurface Ocean Likely Exists Today

MARSDAILY
Chemical Trail Could Lead To Clues About Life On Titan

Chemical trail on Titan may be key to prebiotic conditions

An Ocean Lies a Few Kilometers Beneath Enceladus's Icy Surface

Cassini goes up and over for final mission tour of Saturn

MARSDAILY
SIIS started KOMPSAT-3A commercial services

Vision through the clouds

Experts call for satellite tech to be used in Africa's anti-poaching efforts

Sentinel-1 satellites combine radar vision

MARSDAILY
Mathematical framework prioritizes key patterns to accelerate scientific discovery

A decade of plant biology in space

Exploring inner space for outer space

Quantum technologies to revolutionize 21st century

MARSDAILY
Lush Venus? Searing Earth? It could have happened

A surprising planet with three suns

Teenagers at Keele University Discover Possible New Exoplanet

What Happens When You Steam a Planet




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement