The planetary discovery of the decade may have just been made by a UA alumnus.
Lujendra Ojha and his team, for the first time ever, have discovered proof of liquid water on the surface of Mars—a discovery that can have tremendous implications for the future. The discovery was first made by Ojha during his time as a UA undergraduate using the High Resolution Imaging Science Experiment, a high resolution camera aboard the Mars Reconnaissance Orbiter, or MRO.
In 2011, when Ojha was an undergraduate UA student, he began independent research under the supervision of Alfred McEwen, UA professor of planetary geology and principal investigator for HiRISE. The main findings of Ojha’s 2011 research project suggested that recurring slope lineae—areas on Martian slopes that appear to flow during warm martian seasons—may be caused by water. If water was present, it would have to be briny given that the surface of Mars had been found to be salty.
Over several months, Ojha and McEwen were able to remove distortions like shadows from the images from HiRISE and clearly saw RSL changing over time. What Ojha’s undergraduate study could not determine was that RSL were definitively caused by briny water and could only provide the best explanation for RSL. In 2011, Ojha’s long term goal was to determine if RSL were caused by water and how likely it is life could survive in those conditions. With new research, Ojha has succeeded in finding the first evidence of liquid, briny RSL on Mars.
Research shows water on Mars and it’s all happening right here at The University of Arizona! Watch UATV’s video of this research.
For years RSL on Mars have puzzled scientists. RSL have been seen by HiRISE since the MRO’s launch in 2005. These RSL appear annually, grow incrementally over time and are strongly correlated with solar heating. RSL often follow small gullies and can reach up to 100 meters in length. Until Ojha and his team began their research, it was only hypothesized that RSL were caused by water or frost. However, Ojha has been able to find direct evidence suggesting RSL are caused by salty water.
Ohja and team looked at four different Martian slopes where RSL appeared using HiRISE and the Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM, aboard the MRO. CRISM is able to take spectral measurements of the Martian surface. This allows researchers to identify minerals and other elements present on the surface by analyzing their wavelengths from visible to infrared. Different minerals produce different wavelengths, which was crucial to Ojha’s research. Using CRISM, Ojha was able to determine the composition of RSL, finding that they were composed of hydrated salts.
Their main spectral findings suggest that the salts present on Mars are magnesium perchlorate, magnesium chlorate and sodium perchlorate. Given the high salt content, the water on Mars was able to remain a liquid despite the planet’s cooler surface temperatures.
The presence of perchlorates is controversial regarding the presence of life, however. Perchlorates in high concentration could be toxic to life, as they make the water so salty; but perchlorates are also used in certain metabolic processes to support life according to Scott Murchie, a researcher from Ojha’s team and principal investigator of CRISM. The current data on RSL does not provide insight about the concentration of perchlorates in the water, just the existence of perchlorates. Until the concentration of perchlorates is known, it will be difficult to tell whether life could survive in these conditions.
“The key question is going to be what is the salinity of the water that forms,” Murchie said.
Finding briny, flowing water on the surface could lend credence to other water present on Mars, possibly less salty and more hospitable. Matt Chojnacki, another researcher on Ojha’s project and HiRISE associate staff scientist, suggests that while the brine found on the surface could potentially be unfavorable for primitive life, water the is key ingredient to forming life and could possibly be found elsewhere on the planet in a more usable state.
As for Ojha’s research in 2015, he was the lead of the team of seven continuing his previous research from four years earlier. After making the initial discovery, Ojha took charge of analyzing the spectral data on his newest research project. Ojha’s research strongly suggests briny water on Mars is causing RSL. While it’s known that the source of the water is not from ice melt, it is still unknown where the water is seeping from. The perchlorate concentration is also unknown at this time and more research needs to be done, however this is a major breakthrough in planetary science.
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