The Secret Behind Mars’ Dark Streaks

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Dark Streaks On Mars
Image Courtesy: NASA/JPL/University of Arizona

Having a home away the Earth might be exciting and thrilling for some. Materializing this dream requires a lot of research and planning. Of all the planets studied by revered researchers and scientists of NASA, Mars is believed to be the only planet where there is some hope of life. The conception of life on Mars received a big boost on the discovery of dark streaks referred as recurring slope lineae (RSL) on the Martian planet. The streaks are said to be evidence of water near or on the surface of Mars.

The mysteries behind the streaks are yet to be uncovered. A recent study by researchers at the University of Colorado, Boulder, reported that the streaks containing hydrated-salts might have come from the atmosphere rather than from the surface of the planet. The RSL first discovered by Mars Reconnaissance Orbiter (MRO) in 2011, appears to decline and regrowth sporadically. The dark streaks act differently in warm and cold climates. The streaks tend to darken and flow down slopes in warm seasons and disappear in cold climates. As per a NASA press release dated Sep 28, 2015, the streaks are found at various locations on the Red Planet. These streaks are formed on steep and relatively warm slops.

The latest report is based on a lab experiment in which anhydrous (dry) salts were exposed to an atmospheric condition similar to that of Mars. During the experiment, it was found that dry slats such as calcium perchlorate became hydrated when exposed to the Mars-like atmosphere. The findings are in their initial stage and further studies are required to be conducted before drawing any conclusion.

The MRO has been monitoring the Mars with its six super technical tools since 2006. Water is very important for the existence of life on Mars. Therefore, the investigation on whether there is water at or near the surface of Mars is of utmost importance. Even the frozen form of water – ice can prove to be an important resource for human on the planet. If there is frozen or liquid form of water, then researchers might plan to send astronauts on Mars. If not, there is no way we could know as what is happening on the planet without the help of MRO.

Frozen form of water has been indicated at the various places of the planet from time to time by Fresh crater impacts and other data. The icy water has been primarily found in middle and high latitudes of Mars. It is believed that if RSL indicates water, there is a possibility of water-access sites on the low latitudes.

There are various theories supporting the dark streaks. One of the theories believes that the dark streak formed because of an underground layer of water that somehow reached the surface of canyon ridges isolating peaks. Most of the dark streaks are found on canyon ridges.

Again, there are various hypotheses supporting the presence of liquid water for the formation of dark streaks. Still, researchers have not openly ruled out other hypotheses. One of the hypotheses believed that the streaks were formed as when salts and water vapors interacted. To believe the scientists, streaks might be the leftovers of the salt when it interacted with water vapors, pulled from the Martian atmosphere. The interaction resulted in the creation of ‘liquid brine’ which means an excess of salt in the water. The dark streaks might be the leftovers of the salt when brine evaporated.

Further studies are expected in 2018 after a planned rover visit on the planet. The upcoming study will meet strict requirements for sterility. Scientists believe that once Mars had flowing rivers and was a warmer and wetter planet. Today, most of the water that once used to flow on the planet is locked up as ice, which can be found in polar ice caps and in sub-surface glaciers. Various studies have also hinted at the presence of water vapors in the atmosphere of the planet. However, the stability of the water on the surface of the red planet is a matter of question because of the freezing temperature and low atmospheric pressure.

As stated before, it is quite early to draw a conclusion. But, to say that there isn’t any life on Mars would be completely wrong because chemical reactions  and breakouts of the streaks are a sign that at least something is living on the Martian planet that we need to watch very carefully. The NASA is closely watching each and every activity on the planet through its MRO. More images are expected in the future, which may further support or rule out the conception of water and life on the planet. Till then we all have to wait patiently.