The latest bomber to make its debut over Iraq has four engines, no cockpit, and a flight time limited by the length of its battery. ISIS, the radical insurgent group holding territory in both Syria and Iraq, is fighting for its life in Mosul, the large city in Northern Iraq it has held since 2014. Most of the weapons ISIS uses are are familiar, if still horrific: rifles and mortars, artillery and suicidal car bombs. To that arsenal, ISIS recently added commercial drones, converted into tiny bombers.
You could call it a rainy-day fund. A team of MIT researchers has built an all-liquid battery prototype that's designed to store excess energy from solar and wind power plants. When the sun isn't shining, or the wind isn't blowing, future versions of this battery could release energy captured during more productive times into nations' power grids.