It’s as if salty tears of joy are streaking Mars’ dusty face while the planet struggles to contain its emotion. A bit melodramatic? Perhaps, but news of water on Mars has recently grabbed the red planet an impressive amount of fanfare.
For a team of scientists, their finding was simply an incremental step in research confirming what they considered to be a forgone conclusion. But it quickly ballooned into a massive story that captured the public’s imagination.
NASA got the ball rolling with a provocative bulletin, boasting “NASA to Announce Mars Mystery Solved.” Days after NASA’s press conference the frenzy was still going strong as the public made the leap from water to the possibility of life on Mars. The finding even made the rare transition from science news to pop-culture phenomenon, and no one was more surprised than the researchers themselves, including team member Matthew Chojnacki. “It was crazy, it was on the Daily Show, and Bill Maher, and late night shows, and Rush Limbaugh said it was a liberal conspiracy and I mean, like, are you kidding?” exclaimed Chojnacki.
When analyzing digital images from the Mars Reconnaissance Orbiter in 2011, researchers had discovered dark streaks on Martian crater walls and hills, but could not confirm if these were salt marks left behind by liquid water. “We felt like the data favored it and that it was a matter of time, but it was going to be difficult because of the limitations of the orbital data…so there was a new technique that needed to be applied,” Chojnacki explained.
In their most recent study, the team developed a new approach to figure out the composition of the streaks. The used a special infrared camera on the Orbiter to look at light reflected by the dark swaths. Different minerals reflect the light at different wavelengths, giving them recognizable signatures that scientists can use to identify them. The pattern of light reflected by the streaks told the researchers that they are, indeed, made of salt, more specifically perchlorates left behind by briny, flowing water. The water cycles between a flowing liquid early in the morning and a solid salt with water locked into it later in the day, much like early morning dew that evaporates by the afternoon.
And while NASA may claim that the mystery is solved, the researchers are already turning their attention to the next step in their work—tackling a myriad of questions about the water, including where it comes from, how it cycles, and how much is there. For now at least, a hunt for life on Mars will have to wait.