The recent discovery of liquid water on Mars marks the start of a new relationship with the red planet. Findings from NASA's Mars Reconnaissance Orbiter (MRO) have detected signatures of hydrated minerals that come and go with the seasons, with spectrometer observations showing signs of liquid salty water. People are already speculating about the implications of these findings, with microbial life, fresh drinking water, and even human colonisation all on the agenda.
The water on Mars ebbs and flows with the seasons, flowing down gullies and darkening the Martian surface along downhill flows known as recurring slope lineae (RSL). While scientists have known about these mysterious streaks since 2010, no direct detection of water was made until very recently. According to John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington, “Our quest on Mars has been to ‘follow the water,’ in our search for life in the universe, and now we have convincing science that validates what we’ve long suspected."
Now that water has been found on Mars, people are wondering what's next. While evidence of flowing water is not the same thing as finding life, the existence of extreme life forms on the red planet now seems a little closer to reality. The salty water on Mars may be capable of sustaining chemical reactions and supporting extreme forms of microbial life under the right conditions. The odds of finding life are small, however, with the type of salts found near the Martian streaks - perchlorates - toxic to many forms of life, including humans.
Speculation is also rife on the future of Martian exploration, with the existence of water likely to accelerate existing space programs. Big questions remain about the origin of the water, however, which either comes from underground or has an atmospheric origin. If the water comes from some kind of underground aquifer or buried icefield, humans may be able to tap into it. The more likely scenario, however, is that the water has an atmospheric origin, with surface salts absorbing water vapour in the Martian atmosphere.
Future exploration also hinges on the possibility of contamination, with NASA worried about Earth microbes hitch-hiking on spacecraft and contaminating the Martian surface. Not only would contamination complicate the future detection of life on Mars, the introduction of invasive species could also alter the pristine Mars environment. “It’s hard to get a spacecraft clean enough to send a lander or rover there right now,” says Bethany Ehlmann, a planetary geologist at Caltech.
Despite all these challenges, the discovery of water on Mars has already led to renewed interest in the red planet. According to Michael Meyer, lead scientist for NASA’s Mars Exploration Program, “It took multiple spacecraft over several years to solve this mystery, and now we know there is liquid water on the surface of this cold, desert planet... It seems that the more we study Mars, the more we learn how life could be supported and where there are resources to support life in the future.”
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