Why we should all be excited about water on Mars!

Michelle Collins Oct 01, 2015

I know, I know. You've heard it before. NASA announces water on Mars! Didn't they do that years ago? Don't we already know all about water there? What's the big deal?

Well, my friends, this time things are a little different. It's true: we did already know there was water on Mars. But the water that's been discovered in the past is ancient, locked up in ice caps or in the atmosphere, and not doing a whole lot. This latest discovery implies that water is flowing on the surface of Mars, creating dark, salty streak lines known as recurring slope lineae. Which is MUCH cooler than boring ice*.

So, how was this flowing water discovered?  Dark streaklines on Martian mountains were first spotted by the lead author of the study, Lujendra Ojha, when he was but an undergraduate student at the University of Arizona in 2010. He noted that these dark lines, looking much like downhill flows, would 'ebb and fade' with the seasons, appearing when the temperature rose above -23 C (-10 F), and disappearing as the temperature dropped again. He and his team suspected that these streaks were being caused by water, so they pointed the Mar Reconnaissance Orbiter (a satellite in orbit around Mars) at the features to take spectroscopic measurements of the surface. What they found were hydrated salts - known as perchlorates - in the dark streaks. And this observation is the smoking gun for proving that these dark streaks are caused by water flowing along the Martian surface!

And why is flowing water important? Because if water flows on the surface of Mars, the chances of finding life there are improved. If Mars used to have lots of water, then it would have possibly supported life in the past. So ice caps and evidence of ancient rivers and oceans imply that we might find evidence of past life on Mars. Flowing water makes it more likely that there could be some hardcore Martian microbes living it up on the red planet right now, at the present day. It could also make future human missions to Mars easier, as now we know a bunch of locations where water could be collected by future Martian explorers. If Mark Watney had known about them, it might have made things a little easier in 'The Martian'. 

The water may not be 'ideal' for life as we know it though. It's incredibly salty, and is being described as a briny solution. Beyond that, we don't know much about its chemistry. Ideally, we'd send a Rover over and get an up close and personal view of the water. The problem with that is, whatever we send to the flowing water needs to be sterile, i.e., uncontaminated by pesky Earth microbes that would contaminate the samples, leading us to draw all kinds of spurious conclusions about these streams. Which means that, currently, the Curiosity Rover is not allowed to go and check out these dark streaks. It will only be able to observe them from a distance. So it may be some time before we can assess these watery findings, and search for life on our red neighbour.


So for now, we'll just have to wait for NASA's next move. And hope for more exciting Mars missions in the future. There's so much to learn about Mars! And plenty of reasons to be excited about it. Just like the folks on Twitter already are :)

* Ice isn't boring really... it has 'cool' implications too (see what I did there??). Any water implies that past-Mars may have been capable of sustaining life. So, NASAs Mars Mantra is to always 'Follow the water" in the hopes of finding evidence of life at any stage in Mars' past.