by: Chris Thompson
Once again, Across the Margin cranks up the voltage and points its high-powered antennas towards Mars…
Commonly thought to be one of the key prerequisites for extraterrestrial life, NASA confirmed yesterday, in a prodigious scientific announcement that brings us one step closer to knowing if we are truly alone in the universe, that liquid water does indeed exist on Mars. This is a HUGE scientific discovery, and I am finding myself completely floored and in utter awe of this historic announcement. Essential to all known forms of life on our own oceanic world, liquid water has been elusive on Mars’s surface. With water existing solely as ice, or in the planet’s thin atmosphere as vapor, it was only speculated that water was able to survive as a liquid on Mars’s desolate lands. Owing in a large part to the planet’s low, low atmospheric pressure (just 0.6% of Earth) and its crushingly frigid surface temperatures (minus 84 degrees fahrenheit), it was difficult to imagine this vital, universal liquid flowing freely on Mars’s dusty, cratered surface. But with Monday’s announcement – definitive evidence of liquid water on Mars coming in the form of salty water outflowing from the Red Planet’s deep canyon walls, sloping hillsides and numerous craters – it is hard to not get excited about what the implications for this finding brings.
Thought to be formed by briny water, which freezes at a lower temperature than pure water, the waterlogged salts outflowing from Mars’s landscape appear to occur in the planet’s warmer months, and have been termed Reccurent Slope Lineae (RSL’s) by the scientists involved in their discovery. Seasonal in nature, the streaks were observed in photographs by the Mars Reconnaissance Orbiter back in 2012, appearing as dark lines creeping down canyon walls and cratered hillsides, that grew in length over time and ebbed and flowed with the planet’s shifting temperatures, returning annually. Formed by an underground flow of briny water that is thought to bathe Mars’s sub-surface and make it wet, it was the perchlorates (a type of salt) in the streaks that allowed “a direct detection of water in the form of hydration of salts,” according to Dr. McEwen, a scientist and co-author of the paper, published in Nature Geoscience, in which the waterlogged molecules were first described.
According to Dr. McEwen, “There pretty much has to have been liquid water recently present to produce the hydrated salt.” Hinting that the perchlorates the team discovered in the Mars Reconnaissance Orbiter’s images had to have been made within days, not weeks or years, of when they were detected. The fact that these bold scientists are able to place the history of these salty outflows in a timeframe that to us is understandable, and not measured in thousands or millions of years, further lends evidence to the fact that what was once considered a dry, and uninhabitable planet, may very much be “alive.” With the perchlorate salts lowering Mars’s waters freezing temperature and the fact that at the planet’s Equator, in the summer months, the temperature can hover around 70 degrees fahrenheit (that’s Florida in December weather baby!), this makes for ideal conditions, suitable for liquid water to exist at the planet’s surface. Likened to the darkening of hardened concrete when water flows across and is absorbed by it, the darkened streaks have been observed thousands of times since their discovery and the perchlorate salts, detected by orbit at four different locations, disappeared in tandem with the dark streaks, lending further evidence to their existence in a “hydrated” form. The source of the subsurface water on Mars still remains a mystery, one that I am confident the inventive, resourceful and wildy curious scientists scrutinizing Mars with their legion of satellites and robots will surely solve, but until that moment arises, there can be only speculation as to where the water comes from. Speculation that is sure to occupy my imagination and daydreams for weeks to come.
Palikir Crater shows darkened streaks expanding during Mars’s warm summer months and then disappearing as the planet cools.
In the past, we didn’t have a good way of describing how life might presently survive on Mars, but now with this groundbreaking discovery, it’s clear that we do. With each new finding comes the question of whether a planet as dry and inhospitable as Mars is capable of supporting life. And now that one of life’s key ingredients, liquid water, has been discovered, the question seems even more relevant than ever before. I have spoken of my excitement with this possibility numerous times in the past, and what keeps coming to my mind is the way in which organisms on Earth adapt to seemingly inhospitable environments. We have discovered life existing, and even thriving, within some of the most violent, toxic and uninviting places on this planet. And each time we discover another microorganism, another version of life, be it living deep, deep underwater near boiling “black smoker” volcanic vents, or way up in the arctic buried under miles of crushing, froze ice, or even hundreds of miles up in the sky, flourishing within the clouds, we are forced to redefine what we mean by “life.” In all of these harsh environments where we reasoned life could not exist, there is water, the giver of life, and if life can evolve and survive in places we never considered possible, what’s to say that there aren’t little recesses of habitability somewhere on Mars? Maybe life is buried in some briny, darkened cavern deep underground, where it’s just waiting for us to come find it? And in finding it, we change our understanding of the world? The way I see it, all the pieces to the story about our position in the universe are starting to fall into place, and despite my blind optimism and faith in the fact that life exists on Mars, I still can’t help but feel a childlike sense of wonder every time NASA peels back another Martian layer, and in doing so, brings us one step closer to not feeling so alone.