MIT researchers have built a turbine engine with blades that span an area smaller than a dime and spin at more than a million revolutions per minute.

The engine is designed to produce enough electricity to power handheld electronics. In the future, a micro gas turbine engine could run for ten or more hours on a container of diesel fuel slightly larger than a D battery; when the fuel cartridge runs out, a new one could be easily swapped in. Each disposable cartridge would pack as much energy as a few heavy handfuls of lithium-ion batteries. So a small pack of the cheap and light cartridges could power a PDA or cell phone through several days of heavy usage, no recharging required.