There's no predicting the exact movements of the oil spill—which is growing by at least 5,000 barrels (210,000 gallons, or 794,937 liters) a day. But winds could push the slick south, where oil might get swept into the current.

Born in warm Caribbean waters, the Loop Current pulses north into the Gulf of Mexico and travels in a clockwise pattern toward Florida—ending up in one of the oceans' mighty conveyor belts, the Gulf Stream. (See a Gulf of Mexico map.)

If oil is swept up into the Loop Current—which moves at about 3.3 to 6.5 feet (1 to 2 meters) a second—"there's essentially no way to stop it," said Tony Sturges,