Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Flowing Water on Mars Appears Likely But Hard to Prove

11.02.2014
Studies examine puzzling summertime streaks

Martian experts have known since 2011 that mysterious, possibly water-related streaks appear and disappear on the planet’s surface. Georgia Institute of Technology Ph.D. candidate Lujendra Ojha discovered them while an undergraduate at the University of Arizona.


Dark flow like features called Recurring Slope Lineae emanating from bedrock exposures at Palikir crater on Mars during southern summer. These flows are observed to form and grow during warm seasons when surface temperature is hot enough for salty ice to melt, and fade or completely disappear in cold season. Arrows point to bright, smooth fans left behind by flows.

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, searching for minerals that RSL might leave in their wake, to try to understand the nature of these features: water-related or not?

Ojha and Georgia Tech Assistant Professor James Wray looked at 13 confirmed RSL sites using Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) images. They didn’t 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.

“We still don’t have a smoking gun for existence of water in RSL, although we’re not sure how this process would take place without water,” said Ojha. “Just like the RSL themselves, the strength of the spectral signatures varies according to the seasons. The signatures are stronger when it’s warmer and less significant when it’s colder.”

The 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’s conditions by the time CRISM observes them in the mid-afternoon.

The findings were recently published in Geophysical Research Letters, and the Georgia Tech duo’s newest paper, published in the journal Icarus, indicates that predicting where RSL will appear is, at best, a guessing game.

Ojha, 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.

“Only 13 of the 200 locations had confirmed RSL,” said Ojha. “There 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.”

Comparing 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 – there one year, gone the next.

“NASA likes to ‘follow the water’ in exploring the red planet, so we’d like to know in advance when and where it will appear,” Wray said. “RSL have rekindled our hope of accessing modern water, but forecasting wet conditions remains a challenge.”

Ojha and Wray are also among several co-authors on another RSL-related paper published this month in Nature Geoscience. That study, led by the University of Arizona’s Alfred McEwen, found some RSL in Valles Marineris, near the Martian equator.

Jason Maderer | EurekAlert!
Further information:
http://www.gatech.edu
http://www.news.gatech.edu/2014/02/10/flowing-water-mars-appears-likely-hard-prove

More articles from Earth Sciences:

nachricht Oceans may be large, overlooked source of hydrogen gas
21.07.2016 | Duke University

nachricht Groundwater discharge to upper Colorado River Basin varies in response to drought
21.07.2016 | US Geological Survey

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

Im Focus: A Peek into the “Birthing Room” of Ribosomes

Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis

A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...

Im Focus: New protocol enables analysis of metabolic products from fixed tissues

Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.

In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...

Im Focus: Computer Simulation Renders Transient Chemical Structures Visible

Chemists at the University of Basel have succeeded in using computer simulations to elucidate transient structures in proteins. In the journal Angewandte Chemie, the researchers set out how computer simulations of details at the atomic level can be used to understand proteins’ modes of action.

Using computational chemistry, it is possible to characterize the motion of individual atoms of a molecule. Today, the latest simulation techniques allow...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

Hey robot, shimmy like a centipede

22.07.2016 | Information Technology

New record in materials research: 1 terapascals in a laboratory

22.07.2016 | Physics and Astronomy

University of Graz researchers challenge 140-year-old paradigm of lichen symbiosis

22.07.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>