Southwest Airlines is ending its unique open-seating policy after more than 50 years. The airline said its research found 80% of customers preferred assigned seating.

UNLV medicine professor Edwin Oh had a simple question for his young students. “Do you see green cells?” If they said yes — and, happily, they all did — that meant they had successfully transfused a special protein into a small dish of human kidney cells that allowed the cells to glow green when placed under a beam of blue light emitting from a high-powered fluorescent microscope.

The question of whether Mars ever supported life has captivated the imagination of scientists and the public for decades. Central to the discovery is gaining insight into the past climate of Earth’s neighbor: was the planet warm and wet, with seas and rivers much like those found on our own planet? Or was it frigid and icy, and therefore potentially less prone to supporting life as we know it? A new study finds evidence to support the latter by identifying similarities between soils found on Mars and those of Canada’s Newfoundland, a cold subarctic climate.