There’s water on Mars - but is there life?
Theres water on Mars - but is there life?
Some scientists think the answer might lie underneath the Martian surface
By Kate Lunau, Macleans Magazine,. September 28, 2015
This image shows the central peak in Porter Crater. Although there are no repeat images here we can infer several active geologic processes, based on morphologic evidence and lessons learned from past well-monitored sites. (NASA/JPL/University of Arizona)
Over a century ago, astronomers looking up at Mars thought it was covered by a network of watery canals, built by an alien civilization. When better telescopes showed this wasnt the case, a new view of the red planet took hold: one of a barren, freeze-dried desert, completely inhospitable to life. More recently, weve learned that, billions of years ago, a young Mars was warmer, wetter, and much more Earthlike than it is todayand now our picture has evolved again. In a stunning announcement, NASA scientists say theyve found signs of salty liquid water at the surface of present-day Mars. This discovery suggests it would be possible for there to be life, today, on Mars, says John Grunsfeld, a former astronaut and NASAs associate administrator for science.
Evidence comes in the form of long, narrow streaks that descend down valleys and craters, which darken during Martian summertime and fade away when its colder. Using an imaging spectrometer on NASAs Mars Reconnaisance Orbiter , scientists found evidence of hydrated salts, which would significantly lower the freezing point of briny waterlike the road salt thats tossed on frozen roadways during Canadian wintersand allow it to flow. These hydrated minerals, called perchlorates, are necessary to keep liquid water around. Pure liquid water is highly unstable on Mars, observes Lujendra Ojha, of the Georgia Institute of Technology, lead author of the paper published in Nature Geoscience ,who first observed the streaky formations back in 2010. A glass of tap water on the surface of Mars would freeze or boil away, but some perchlorates can keep liquids from freezing when its as chilly as -70C.
Could such a briny solution support life? Here on Earth, bacteria thrive in all sorts of apparently inhospitable places. Theyve been found living in salty veins of water in the High Arctic permafrost, in Antarcticas underground lakes , or beneath Chiles super-dry Atacama desert . We dont know where the Martian water flows come from, and if they might indicate an aquifer beneath the surface. University of Toronto geologist Barbara Sherwood Lollar has found ancient water buried deep underground at sites in northern Ontario and South Africa, rich in the types of chemical energy that could support microbial life. If its too salty, it can limit life, but if its not too salty, it can be advantageous, she says. In the deep systems that we look at, the presence of salt is an indicator of extensive water-rock reaction, and we see a lot of energy-rich compounds that can serve as a food source for micro-organisms. In our research, she says, salt is a good thing.
Some scientists believe that if we find microbial life anywhere on Mars, itll be under the surface. The European Space Agencys 2018 ExoMars mission will carry a drill that can get at soil samples two metres deep. NASAs next Mars rover, scheduled for 2020, which will directly seek signs of ancient life. Soon, I hope well be sending humans to the red planet to explore, Grunsfeld says. Not so long ago, the idea of flowing water on Mars seemed fanciful; today, scientists say its there. Our planetary neighbour remains full of surprises.
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This is a Very Big Deal.
But I'll go along with the author: we need to know a whole lot more before we can evaluate just how Big.
It is a big deal, just how big is yet to be determined.
Any water can mean that it will support life-- but it doesn't necessarily mean that there is life. Given more time and study, as well as technological advantages, perhaps we can think of it as a possibility for colonization.
If there is life there-- I hope we leave it alone.
VERY true!