Mars’ Recurring Slope Lineae Most Likely Caused by Boiling Water
Researchers previously thought that the recurring slope lineae (RSL), or the dark streaks in slopes, in Mars are caused by dust avalanches or venting of carbon dioxide gas, but a new study suggests that the strange features in Martian slopes is most likely to be caused by boiling water.
According to the study published in the journal Nature Geoscience, low atmospheric pressure in Mars can cause water to boil easily even at low temperatures.
The effect of atmospheric pressure in water can be easily understood using Mt. Everest. The atmospheric pressure at the top of Mt. Everest is 400 millibars, while at normal sea level, the atmospheric pressure can reach around 1,000 millibars. If you try to heat water at the top of Mt. Everest, it will come to boil even at 72 degrees Celsius, while boiling water at sea level requires a temperature of 100 degrees Celsius. Now, imagine the possible behavior of water in Mars where the atmospheric is only about five to ten millibars.
In order to know if boiling water is the cause of the recurring slope lineae in Mars, researchers tried to recreate Martian conditions by using loose, fine-grained sand and the Large Mars Chamber, a steel decompression chamber that can lower atmospheric pressure, at England's Open University.
Researchers set up a slope of sediments in the lab under both Earth's and Mars' condition. They then placed a block of ice at the top of each slope.
Researchers observed that at Earth-like temperature and air pressure that the water from the melting ice cube just dribbled in the sand darkening it but unable to move it.
However, under Martian conditions, the water melted from the ice seeped into the sand and began to boil. As a result, sands were fling down the hill piling up until their heaps collapses triggering an avalanche.
As the melting and boiling process continues, researchers observed the development of small channels that are quite similar to Mars.
According to the report from Space.com, the findings suggest that it is still probable that water exist in Mars, due to the viability that water causes RSL, but at the same time the study also shows that very less water is need and that water produced in Mars can only exist for a very short time, which means it is still not able to serve as a valuable environment for advance microorganisms.