Last December, US scientists launched a robotic glider in the Caribbean. The yellow, torpedo shaped glider won't be detonating anytime soon; it was sent to gather oceanographic data.

What's amazing about the glider is that it has a virtually unlimited energy supply: ocean heat. It's propulsion needs no batteries to run at all.

It can't totally do without batteries though. Its data gathering system, like its sensors and satellite communications system, still needs batteries so it needs to go back to a power source every now and then.

This type of glider will be common in monitoring oceanic activity in the future. Their data will be important in studying ocean currents, circulation and other surveys. As the BBC reports, the latest glider was developed by the Webb Research Corporation and the Woods Hole Oceanographic Institution and was launched in the Carribean last December.