
Images of the Martian surface sent back by the Mars Reconnaissance Orbiter (MRO) are helping scientists confirm a mystery that has long been pondered and debated: Is there liquid
The short answer: Yes. Thanks to findings published today in the scientific journal Nature Geoscience, scientists now know there is salty liquid
The news is also being confirmed by an announcement from NASA HQ by Jim Green, director of planetary science; Michael Meyer, lead scientist for the Mars Exploration Program; and Mary Beth Wilhelm of NASA’s Ames Research Center.
How did they make this discovery? After analyzing the planet’s features based on density and light absorption over the past few years, scientists have noticed dark streaking on the surface that points to the existence of rivers and streams. Today, their new observations show a directional tide and flow to these areas, which are cyclical and coincide with warmer seasons.
This indicates freeze and thaw—a sure sign of the existence of liquid

The current presence of this essential building block for life has astrobiological and geological implications that will affect how we approach human exploration and future colonization of our neighboring world.
The potential for continuing life on Mars in any form heavily depends on whether liquid
Various salts have been detected on Mars along the darker streaks where
Scientists have always theorized that the dark streaks—known as recurring slope lineae (RSL)—appear on the surface when the temperature is warmer and fade when the temperature drops due to the presence of liquid
Spectral imaging from a tool called the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Orbiter now proves the streaks are in fact caused by downhill-flowing salty

The CRISM instrument has collected data from four different locations where RSL are present and found evidence of hydrated salts at all four locations in the seasons when recurring slope lineae are most prominent.
The discovery of these hydrated salts supports the theory that the RSL form as a result of current
Two of the primary authors of the paper detailing these new findings, Alfred McEwen and Lujendra Ojha, have been searching for definitive proof of liquid
Mr. Ojha, a Ph.D. candidate in planetary science at Georgia Tech, previously made headlines as an undergrad at the University of Arizona where he co-authored a study with Mr. McEwen that suggested liquid
Mr. Ohja noticed unusual features on the images from a study by UA researcher Colin Dundas that looked at gullies in Mars craters. After cleaning up the images by using a computer algorithm to remove distortions and shadows, Mr. Ohja was able to show changes in the landscape over time that revealed the dark streaks. This was the first indication of possible flowing salt

After the NASA news conference back in 2011, Mr. Ojha said, “There’s going to be years of research put into this to even prove that this is definitely a proof of
It seems that just four years later, Mr. Ohja has his proof.
Robin Seemangal focuses on NASA and advocacy for space exploration. He was born and raised in Brooklyn, where he currently resides. Find him on Instagram for more space-related content: @not_gatsby