Sailing among the stars: how photons could revolutionize space flight
A few days from now, a SpaceX Falcon Heavy rocket will lift off from Florida, carrying a satellite the size of a loaf of bread with nothing to power it but a huge polyester "solar sail." It's been the stuff of scientists' dreams for decades but has only very recently become a reality. The idea might sounds crazy: propelling a craft through the vacuum of space with no engine, no fuel, an