Scientists have discovered a new phenomenon on the surface of Mars which can potentially prove that seasonal water, and therefore life, could exist in the red planet.
The decades-long study of Mars has already established that water exists in the Red Planet in icy form, especially around its polar caps, and beneath the surface. But so far no investigation has shown Martian water flowing like a stream. The new finding can open leads in search for life on Mars, scientists say.
Scientists say the lines on the planet's sloppy surfaces become more visible in the warm season, suggesting that they could have been created by the flow of certain volatile chemicals which boils at low temperatures. These flows then dry up in colder seasons. The strongest candidates are water and carbon dioxide, according to a study by planetary geologists at the University of Arizona.Alfred McEwen, the lead author of the study, which was published in journal Science, says they could exclude carbon dioxide as temperatures were too high for it to exist in the form of frost. This means the flow marks were created in all probability by water.
According to scientists the marks observed in the Martian surface are much like flow marks visible on mountains' rocky face during summer, which were created by the mineral deposits of a seasonal stream that dried up.
The fact that the streaks are visible on the equator-facing side of Mars, which is warm enough to melt ice, heightens the chances that this is created by water, and not by high winds that shape dust into curious patterns. If it is dust, the marks do not necessarily be only on slopes.
The latest study was done analyzing the images taken by NASA's Mars Reconnaissance Orbiter, which is circling Mars currently.
This new finding can help scientists big time in their search for life in Mars. "This is water today, not in the past," McEwen told space.com, pitching a case of briny water should be flowing in some places on the planet's surface.
Earlier studies have shown that salt deposits have existed abundantly in Mars. Besides, water traces were found by NASA's Phoenix Mars Lander in 2008.
"Water today on Mars was suggested previously, but it's not clear if those claims withstood follow-up studies ... That may prove true with this case as well, but for now, this is the best candidate for water today on Mars," McEwen said.
If there is life on Mars, it can be traced now with better precision, as it is certain that the briny water on the red planet will hold clues to extant life. "... if there is extant life on Mars, it might be accessible in these brines, which gives us a new direction as to where to go," said McEwen.
Student Lujendra Ojha, a co-author of the study, said the streaks that extend down some slopes during the warmest months of the Martian year appeared to be fading in winter but re-emerging in the spring. "I was baffled when I first saw those features in the images after I had run them through my algorithm. We soon realized they were different from slope streaks that had been observed before. These are highly seasonal, and we observed some of them had grown by more than 200 meters [650 feet] in a matter of just two Earth months," Ojha said in a statement.
The new flow-lines discovered on Martian slopes are hundreds of feet long, but they are pretty narrow, only about 1.6 to 16 feet (0.5 to 5 meters) wide. This means they are narrower than gullies on Martian slopes detected earlier.
But that does not mean that water on Mars is a rarefied substance. In fact it could be abundant. However, McEwen said the researchers could not say for now what is the source of this new-found water. "It probably has to come from vapor, either from the atmosphere or from subsurface ground ice, or it's coming from brines in the crust that are stable over geological time. But it's all speculation right now — we wish we knew," he said.
Even skeptics have been won over by this new finding. Many scientists who thought it was premature to conclude there was water on Mars have seemingly accepted this study. This is waht a former U.S. Geological survey scientists told the LA Times: "I've been something of a skeptic of the possibility of liquid water right at the surface under present conditions ... and I've been irritated in the past by people immediately jumping to yell, 'Water on Mars!...' "I think they [latest findings] make a very good case. … The story hangs together," said Michael Carr.