Of course, no one has yet brought back anything from the red planet, but spacecraft like NASA’s Phoenix Mars lander have analyzed Martian soil in great detail. It’s available for purchase, and Dr. Guinan bought 100 pounds. “Because they’re students,” Dr. Guinan said. “Also, it may help acidify Martian soil,” said Elizabeth Johnson, a Villanova senior who took the class. Mars soil is alkaline, with a pH of 8 to 9, she said, compared to 6 to 7 on Earth.

Source: New York Times January 12, 2018 20:15 UTC