NASA's Curiosity rover has discovered consistent amounts of water in the Martian soil, implying that the red planet isn't so dry after all.
Thanks to its close proximity to Earth, scientists and laymen alike have long wondered why the surface of Mars is so different from our own. So far, our knowledge of the Martian surface suggests the planet once had an abundance of water, but eventually it dried up or remained frozen near the poles. When NASA sent the Curiosity rover to Mars, part of its mission was to find evidence of this water, along with any signs of organic life. Based on Curiosity's findings, we'll have to change "once had an abundance of water" to "still has an abundance". While it's true that Mars has a distinct lack of lakes, around 2% of the soil actually contains good old H20, implying that the planet isn't nearly as dry as one might expect.
Since 2012, the Curiosity rover has been studying the Gale Crater, a landmark located near the Martian equator. One of the rover's programmed tasks is to gather samples of soil from the ground, heat them to 835C using an internal oven, and measure the results. Along with the sulphur dioxide, carbon dioxide, and oxygen released from the soil, a surprising 1.5 to 3% of each sample consisted of water. That's about two pints of liquid for each cubic foot of Martian dirt.
"We tend to think of Mars as this dry place - to find water fairly easy to get out of the soil at the surface was exciting to me," said Rensselaer Polytechnic Institute's dean of science, Laurie Leshin. "If you took about a cubic foot of the dirt and heated it up, you'd get a couple of pints of water out of that - a couple of water bottles' worth that you would take to the gym." [NOTE: The soil still contains a toxic chemical that impedes thyroid function. Please don't drink Martian water at the gym.]
So how did all this water get here? Scientists suspect that billions of years ago, the entire Gale Crater was flooded with enough fresh water to reach depths of over a kilometer. That's impressive enough, but what's really exciting is how well the soil has retained the water and how easily it can be retrieved. If NASA ever gets around to building that Martian settlement, astronauts should be able to use the soil water as a drinkable resource. After it's taken care of the sulphur dioxide and toxic chemicals, of course.