Watch NASA's Mars helicopter Ingenuity test its blades! (video)

In the 60s "Astronaut happiness wasn’t a factor” says historian David Hitt. On Skylab 4, in 1973, the crew was overworked with packed schedules each day. They told NASA they couldn't keep up. This event is misreported as a "mutiny," but it had big effects. Astronauts now work 9-5, with weekends off.

Fun new "perspective" article about the "bark side" of the water cycle. It discusses the odd "geography" of bark (it's in more places than on tree trunks) and how this relates to unknowns in the water cycle.

Powerful Algorithms Used by Netflix, Amazon and Facebook Could “Crack the Language of Cancer and Alzheimer’s”