The discovery of real, liquid water on Mars opens up a host of possibilities about the existence of life on the Red Planet—including an increased likelihood that we humans might actually be from Mars.
"The water [on Mars] is really crucial," NASA administrator John Grunsfeld said Monday. Combined with the presence of nitrogen and carbon dioxide—both necessities for human life—on the planet, it means that, "Mars is looking more and more like a potential habitat for extant life that could be transferred from Earth—one way or another. Some people say we're Martians. It could go either way."
Even if human life did originate on Mars, there's still much to be discovered before we head (back?) there. "NASA is not Star Trek," joked Jim Green, director of the agency's Planetary Science Division. "We have to find out everything we possibly can."
That little nugget of interplanetary wisdom was tucked into the tail end of a press conference NASA held Monday morning, announcing that researchers had discovered more evidence that there was water on Mars. Specifically, the space agency has found that recurring slope lineae (RSL for short) on the planet contain hydrated perchlorate salts. A few yards wide and the length of several football fields, RSL are analogous to the dark marks left on concrete after it rains. So in other words, NASA has been looking at some streaks on the surface of Mars, and they've determined that those streaks are evidence of extremely salty water.
"When most people talk about water on Mars, they're usually talking about ancient water or frozen water," Lujendra Ojha, one of the experts leading the press event, said in a statement. "Now we know there's more to the story."
The presence of water—albeit extremely briny, undrinkable water—on Mars is a really big deal, and not just for the reasons you might think. NASA researchers have known for more than a decade that Mars contains both ice and water vapor. But the discovery that there is liquid water on Mars—and that the liquid contains perchlorates—means that, as Grunsfeld put it, "Mars has resources that are useful to future travellers."
According to Grunsfeld, a former astronaut who is now the associate administrator of NASA's Science Mission Directorate, the discovery raises the question of whether life did once exist on Mars—and whether we might find any life on Mars today. "The existence of water, even if it's super-salty, briny water, gives the possibility that if there's life on Mars, that we have a way to describe how it might survive," he said.
Beyond the obvious extraterrestrial life questions, the discovery of liquid water on Mars raises the possibility that that water could be purified to create rocket fuel, which is often made out of liquid hydrogen or liquid oxygen. Additionally, certain perchlorates themselves can be used as rocket boosters. Practically speaking, that means it might be possible for future Mars explorers to refuel their journey back to Earth by processing what is already on the planet, significantly cutting the amount of fuel astronauts would need to bring on a Mars mission.
The next step, researchers explained, is for NASA to begin looking fora network of underground aquifers on the planet that might be able to provide a water supply for future travelers to the planet. "Now that we know what we're looking for, we can begin a better search," said Green.
"Mars is looking more and more like a potential habitat for extant life that could be transferred from Earth" said NASA's John Grunsfeld. "Some people say we're Martians. It could go either way."
The fact that liquid water is present inside of the perchlorates doesn't necessarily indicate that Mars currently has a water cycle similar to that of Earth. As NASA researchers pointed out, perchlorates are powerful salts that can literally draw water out of the atmosphere, and can therefore help liquid water survive in harsh environment on Mars, raising water's boiling point on the planet from ten degrees Celsius to 24 degrees Celsius.
But previous discoveries from the Mars Curiosity Rover suggest that Mars did once enjoy some kind of robust water system—there is evidence that the planet's northern half was once largely covered by a massive ocean, and that lakes and streams were also present on the planet's surface.
"Mars once was a planet very much like Earth," Grunsfeld said, "with warm, salty seas, freshwater lakes, probably snow-capped peaks, and clouds and a water cycle." These bodies of water may have covered as much as two-thirds of the planet's surface, he added, "but something happened to Mars and it lost its water."
More than anything, the discovery of liquid water provides an incentive for the space agencies of Earth to keep exploring Mars—the phrase "follow the water" was uttered more than once during the press conference. By 2020, NASA plans to make three unmanned trips to Mars, to explore below the planet's surface, as well as to collect samples that can be brought back to Earth and examined for evidence of life.
And Grunsfeld is optimistic that the NASA will eventually send human missions—homecomings, perhaps—to the planet. "The exciting thing is that we will send humans to Mars—they'll be scientists looking for signs of life, and they'll be able to live on the surface," he said. "The resources are there."
Additional reporting by Devon Maloney.
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