It's an unlikely marriage between state-of-the-art and 40-year-old technology that has yielded extraordinary results.

Signals from seismic sensors left on the lunar surface by Apollo astronauts in 1971 have revealed that the Moon has a liquid core similar to Earth's.

Scientists at NASA applied contemporary seismological techniques to the data being emitted from sensors placed by their colleagues during the U.S. space program's heyday.