University of Arkansas researchers have created a model that might explain how water could produce the flow patterns seen by a spacecraft orbiting Mars.
Research professor Vincent Chevrier and former Doctoral Academy Fellow Edgard Rivera-Valentin, now a postdoctoral associate at Brown University, published their findings in a recent edition of the journal Geophysical Research Letters.
The University of Arkansas researchers studied small flow features originally identified by NASA’s Mars Reconnaissance Orbiter and detailed in a July 2011 paper published in Science magazine. These flow features, which appear and disappear with the seasons and show a strong preference for equator facing slopes, indicate the possible presence of liquid on the Red Planet. Chevrier and Rivera-Valentin have constructed the most comprehensive model to date of the behavior of water-and-salt combinations called brines to show that frozen water could melt, flow and then evaporate, creating these flow features on Mars.
Salts can lower the melting point of water, so the researchers used different forms of salt known to form on Mars to calculate what would melt, how much would become liquid and how long the liquid would last from the time it went from freezing to evaporation. They based their model on soils up to 20 centimeters deep, because beyond that depth the seasonal temperatures would not affect the freezing and melting aspects of the salt-water mixtures.
“We had to find a salt-water mixture that would come and go,” in other words, something not completely liquid or solid, said Chevrier, a research assistant professor in the Arkansas Center for Space and Planetary Sciences in the J. William Fulbright College of Arts and Sciences. They found that calcium chloride fits the bill.
“In one day we could form enough liquid to create these flow features on the surface,” he said. The researcher’s model also explained why the flow features disappeared by incorporating evaporation into the model.
“The easier it becomes to melt, the easier it becomes to evaporate,” Chevrier said. At low concentrations of brine, “as soon as it melts, it evaporates and disappears.”
However, the researchers showed that they could melt enough brine so that it would not completely evaporate, thus creating conditions that might explain the flow features.
Their model fits with the seasonal change in flow observations, with the flows occurring on equator facing slopes and with seasonal changes. Also, high surface evaporation rates as demonstrated in their model explain why, if there is water, it would disappear relatively quickly and why imaging spectrometry on Mars has not identified water signatures.
“No other current model really explains all the observations,” Chevrier said.CONTACTS:
Melissa Lutz Blouin | Newswise Science News
'Frequency combs' ID chemicals within the mid-infrared spectral region
16.03.2018 | American Institute of Physics
Fraunhofer HHI have developed a novel single-polarization Kramers-Kronig receiver scheme
16.03.2018 | Fraunhofer-Institut für Nachrichtentechnik, Heinrich-Hertz-Institut, HHI
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences