Martian sunsets are uniquely moody, but NASA's Curiosity rover captured one last month that stands out. As the sun descended over the horizon on Feb. 2, rays of light illuminated a bank of clouds. These "sun rays" are also known as crepuscular rays, from the Latin word for "twilight.

Hurtling around the Earth at more than 20 times the speed of sound, some of the tiniest life forms aboard the International Space Station are on a mission to feed people on a warming planet.

Seeds of sorghum and cress launched into orbit by the International Atomic Energy Agency are tethered to the capsule via a thin metal box. That's exposing them to more-intense solar radiation in a trial to induce genetic mutations so they can survive hotter temperatures, drier soils, spreading pestilence and rising sea levels.

"Most astrobotany until now has been to test how plants can be grown to feed astronauts for eventual space colonies," Shoba Sivasankar, the IAEA's head of genetics and plant breeding, said at her lab outside Vienna. "This experiment is different because it is designed to help people on Earth adapt to climate change."

Farmers from Argentina to California, France and India are struggling to maintain yields amid global warming, with rising prices for the key crops used to bake bread weighing on political stability. Drought gripping North Africa is curbing local wheat harvests, potentially boosting demand in one of the world's top import regions.