Big news broke yesterday as NASA scientists announced the first direct evidence for water on Mars. Let that sink in for a moment. Water. On Mars. It's very exciting stuff, just in time for the big opening weekend of The Martian. Here's what we've learned so far about this momentous discovery.
The first hints of water on Mars appeared about five years ago, but there wasn't sufficient data on the exact chemical composition of those dark streaks. Since then, NASA scientists have worked diligently to combine the Reconnaissance Orbiter's HiRISE camera images with spectral data from the Compact Reconnaissance Imaging Spectrometer for Mars (or CRISM) to get a clearer picture. And it worked! Per Gizmodo's Maddie Stone:
Images collected by the Reconnaissance Orbiter's HiRISE camera show that "recurrent slope lineae" — dark streaks that resemble flow paths on Martian slopes — appear to be seasonal, fading when inactive and reappearing annually over multiple Martian years. These features alone hint at the presence of flowing water, but the real clincher comes in the form of spectral data, collected by the Reconnaissance Orbiter's Compact Reconnaissance Imaging Spectrometer: Hydrated perchlorate salts within the flow paths. Hydrated salts (which contain water in their molecular structure) are powerful evidence of evaporated brine, possibly from an underground reservoir.
Naturally, NASA released lots of very pretty pictures of the Martian surface to coincide with the announcement; check out this gallery of some of the most eye-popping images. You can find even more photos at NASA's site. Also savour this nifty animation:
For those pondering what it all means, the discovery brings us one step closer to possibly finding evidence of life on Mars — most likely weird microbial life, but life nonetheless. It also stokes the passions of would-be space travellers by raising the possibility that the red planet could be a viable habitat for a future human colony.
A few NASA scientists popped over to Reddit for an AMA to answer all those burning questions about exactly how much water we're talking about (more like a tap water leak than Niagara falls) and whether or not you could drink it (not a good idea). Here are some of the highlights.
All of this is especially exciting in light of the ongoing construction of NASA's next mission to Mars, the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight for short), which will study the interior structure of the planet:
"Exploring Mars' deep subsurface will shed light on how the planet has evolved geologically over time, but InSight could also offer clues about Earth's future and the evolution of rocky planets at large.... According to NASA, the technical capabilities of InSight represent a critical step toward a manned mission to the Red Planet, which the space agency hopes to ship off in the 2030s."
You read that right: a manned mission to Mars, possibly even eventual colonization of the red planet. Some scientists think we might even be able to grow vegetables on Mars: the soil up there is capable of supporting plant germination. In fact, it might even be as good as some of the poorer soils here on Earth.
Ah, but not so fast. Paleofuture's Matt Novak interviewed JPL's legendary Gentry Lee back in 2012, who helped put two landers on Mars — plus two orbiters around it — a good 40 years before Curiosity. He's learned a few things from his years in the trenches. And for all his enthusiasm for exploring the red planet, Lee remains doubtful about a manned mission to Mars:
"I'm not against human spaceflight and I believe that once robots have done what they can do, if they have asked questions that only an interactive intelligence can answer it will be time to send human beings there. But the idea that a human mission to Mars is on the horizon just defies all logic. I see no national or international will that is long enough in perspective or vision — in other words, under the changing political climates around the world — to sustain such an activity at such an enormous cost."
Here's hoping Lee's pessimism proves unfounded, and humanity finds the will to keep reaching for the stars. Until then, we can all flock to see The Martian this weekend.
Image: A still from Lujendra Ojha presentation of the data for NASA today, showing precisely where along the gullies the discovery was made, 2015.