So I already had a post written for today but then NASA called a press conference yesterday with the teaser that there would be the revelation of a ‘major science finding’ in relation to Mars and, dang it, if NASA calls a conference I’m damn well going to write about it. And it’s certainly worth a few hundred words.
In the end they were able to confirm a long held suspicion that there is seasonal flowing of liquid water on the surface of Mars. This is really quite significant and mighty exciting, the reason being that everywhere on earth where there is liquid water we find life; it seems to be the only absolute requisite. Now, we cannot in any way say that this means there is life on Mars, we simply don’t know that and we’re not going to anytime soon. What it does mean, though, is that we have a very interesting candidate region where we might want to target our search on future missions. Or, given we have two rovers already on the surface, maybe we will be able to divert them towards a similar site nearby. Neither robot, Curiosity nor Opportunity, is properly equipped to test for life but they could certainly help provide more clues.
Let’s take a look at what they’ve actually found. The image below, which is exquisite, is a composite of two separate images both taken by the Mars Reconnaissance Orbiter; a satellite equipped with six science instruments. The first image is just a normal old picture of the landscape, no great shakes there, the MRO imaged the entire surface of the planet some time ago. This has then been overlaid with an orthorectified (great word) image which gives it those unusual colourings. As far as I understand it this is a sort of spectrographic analysis and the different colours represent different types of mineral on the surface. The bits we are interested in are the black streaks on the slopes. These are not shadows but the remnants of a salty brine thought to have been created when the summer sun, weak as it is way out on the 4th rock, heated subsurface water ice. The temperature of this mixture is unlikely to have ever got as high as zero degrees Celsius, but due to the high amount of salt in the soil the melting point of the water was brought way down, just like when we add salt to the roads at winter here on the 3rd rock.
The black streaks, called recurring slope lineae, are hydrated salts and show us where the flow probably occurred. To be clear, we have not seen water flowing, it has been inferred from the presence of material that needs liquid water to be formed. The main flow of water would have been just below the surface with some of it wicking up to the top and depositing the hydrated salts that we are now able to detect. The phenomenon was first spotted by then undergraduate Lujendra Ojha in 2010; now, five years on and as lead author in the report published in Nature Geoscience, he is able to confirm what many of us had been hoping was true since that time.
As is normally the case, it is well worth clicking through to NASA’s original hi-res image, it’s a thing of beauty, but more than that are the implications of the findings. The more we study Mars the more niches we find for potential life. Don’t get me wrong, Mars is still a miserable place to go on your holidays, but for bacteria? Well, it’s not impossible to imagine that there could be something lurking in these seasonal waters that are capable of surviving being frozen through the winter. Here on earth we have found bacteria in permafrost that becomes viable upon warming having been frozen for some considerable amount of time. And even if, ultimately, Mars still turns out to be sterile the new data at least gives us an idea of where life might be more feasible in the future. If we ever get to Mars it would be nice to set up camp at a spot where we know that for part of the year at least we are not far from a cold, if salty, beverage.