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" To hear more from the editors of Popular Mechanics, download this week&amp;#039;s episode of &amp;#039;How Your World Works&amp;#039;\u00A0here,\u00A0and be sure to subscribe and comment on iTunes!   Andy Weir&amp;#039;s\u00A0The Martian, a self-published\u00A0science puzzler about an astronaut marooned on Mars with only his wits\u00A0to save him, came out in book form in\u00A02011. On October 3, it hits the big screen as a star vehicle for Matt Damon as the astronaut Mark Watney, courtesy of sci-fi legend\u00A0Ridley Scott. In the four years since the book came out, we&amp;#039;ve learned a lot about Mars (Weir purposely published it just before the Curiosity Rover launched), so Scott turned to\u00A0Jim Green, director of NASA&amp;#039;s Planetary Science Division, to find out how to create an accurate portrayal of the Red Planet. We\u00A0talked to\u00A0Greene about the process of building Mars for Hollywood audiences. Turns out that there&amp;#039;s a lot that&amp;#039;s recognizable for those of us stuck on Earth.  Climate Change Has Taken Its Toll Three billion years ago, half of Mars&amp;#039; northern hemisphere was covered with water. Today, most of the water from that ocean has evaporated, and what&amp;#039;s left has largely gone underground. Interestingly, the astronaut&amp;#039;s destination in the film is in a part of Mars where the groundwater is relatively close to the surface. According to\u00A0Green, Watney could have thrown a grenade, blown a hole in the ground, and picked ice out of it*. *Note: NASA does not endorse the wanton use of explosives. Martian Weather Forecasting\u00A0Is\u00A0Terrible We actually have forecasts of Martian weather.\u00A0The Mars Climate Modeling Group runs on supercomputers at NASA&amp;#039;s Ames Research Center in Mountain View, California, and predicts things like wind speed, temperature extremes, and dust storms. The catch? Its sophistication level is roughly equivalent to where we were with Earth-weather prediction in the 1960s and 1970s, when NASA helped the National Oceanic and Atmospheric Administration sort out the physics involved in large-scale weather prediction on earth. Its Soil Is Even Drier than California&amp;#039;s One of the coolest things in the book and movie is the way astronaut\u00A0Watney,\u00A0a botanist, develops a technique for growing food in Martian soil. But it turns out that growing food on Mars wouldn&amp;#039;t be quite as grueling as it appears. After the book came out and\u00A0Curiosity finally got to Mars, it not only found groundwater but also detected the presence of nitrates, which are key nutrients for plants. Drivers are Uptight About Dirt in Their Cars NASA&amp;#039;s current designs for manned Martian vehicles include external space closets. Before boarding, astronauts will remove the suits they wear on the planet&amp;#039;s surface and hang them on the outside of the vehicle\u00A0so as to avoid contaminating the cab with dust. They&amp;#039;re Gonna Need Drones While most water on Mars is underground, images of the walls of the Martian &amp;quot;Grand Canyon,&amp;quot; Valles Marineris, suggest water may be weeping out of the surface. It&amp;#039;s something that must be explored. According to Green, while we&amp;#039;ll probably design specialized vehicles to get to places like canyon walls, the way to explore something like this is with drones specialized for the Martian environment. "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.popularmechanics.com/culture/movies/a17504/5-ways-the-martian-nails-the-science/>