For the first time, scientists have confirmed the existence of flowing water on the surface of Mars. It has been long speculated that flowing water must have caused some of the geologic features observed on the Red Planet, but scientists have never found the smoking gun.
In an abstract for the European Planetary Science Congress, a scientific team presents their proof of flowing water on Mars.
The water discovered on Mars is not like the water here on Earth; it is briny water – meaning that there are many mineral dissolved in it like salts. Water as we know it on Earth would not exist on the surface of Mars. It would rapidly evaporate or freeze; however the briny water has a different freezing and evaporating temperature than pure water. The briny water may can freeze as low as -270 degrees C, and evaporate at about 1000 degrees C (10 times hotter than on Earth).
Features known as Recurring Slope Lineae (RSL) are narrow flow features on the surface of Mars that have been long speculated to have been formed by flowing water. RSL are seasonal (meaning they appear and disappear throughout the year) and extend downslope, on sides that follow the sun, in temperatures around -23 degrees C.
Being that it is extremely difficult to check these areas in person for flowing brine water, the research team utilized a remote sensing tool known as a spectrometer to detect the infrared light reflecting off the surface of Mars. Specific materials have a unique signature of infrared light that they either reflect or absorb. In this case, the researchers were looking at the specific wavelengths of light that liquid water and hydrated salts (briny water) reflect and absorb.
Utilizing this technique, the researchers confirmed the presence of briny water at four locations on Mars with RSL.
Like many research projects, this project produced more scientific questions than answers. We know now that there is briny water flowing on Mars, but what is the origin of the water? The team provides three hypotheses. The first hypothesis is that the water comes from melting ice; however, there is no ice near these RSL features with confirmed water flow. The second hypothesis is that the water comes from the atmosphere of Mars, in a process known as deliquescence; however, they don’t know if the Martian atmosphere can sufficiently supply the water. Finally, the water may be a result of a seasonal discharge of groundwater. Unfortunately this hypothesis does not explain why there are RSL features at the tops of peaks.
What we do know is that there will surely be much more research on Mars in an effort to answer the question of where the water is coming from.