Seven faint pings picked up by a British satellite orbiting 22,000 miles above the Earth may ultimately lead to the wreckage of Malaysia Airlines Flight 370. If they do, those elusive, scant clues will represent a first in aviation accident history.

Twenty-six nations have pursued a frustrating search for the Boeing 777, which vanished March 8 without a trace. The best chance of finding the plane rests on using a physics concept developed in the 1840s, known as the Doppler effect, to determine the plane's likely flight path as it moved through the darkness.

That kind of complicated mathematical analysis is commonly used in astronomy but has never before been used in an airline accident investigation.

"This is really unprecedented," says Jonathan