Charles Fishman pens a terrific story for The Atlantic, on the intricacies of everyday life aboard the International Space Station, and the biological implications of living in space for extended periods of time:

On the station, the ordinary becomes peculiar. The exercise bike for the American astronauts has no handlebars. It also has no seat. With no gravity, it’s just as easy to pedal furiously, feet strapped in, without either. You can watch a movie while you pedal by floating a laptop anywhere you want. But station residents have to be careful about staying in one place too long. Without gravity to help circulate air, the carbon dioxide you exhale has a tendency to form an invisible cloud around your head. You can end up with what astronauts call a carbon-dioxide headache. (The station is equipped with fans to help with this problem.)

Via Josh Ginter.