A GPS in a car can precisely navigate a city, but what if a GPS in a spaceship could precisely navigate our galaxy? German scientists are developing that very gadgetry, reports the BBC. This interstellar mapping system would use X-ray signals from pulsars, a type of dead star that rotates at a remarkably exact rhythm. By combining data from the pulses of a pulsar and a reference location, a spaceship could calculate its location in outer space to within 3 miles.
"The principle is so simple that it will definitely have applications," says one physics professor. "These pulsars are everywhere in the universe and their flashing is so predictable that it makes such an approach really straightforward." Mirrors that detect X-rays are too big and unwieldy now, but suitably sized ones could be ready in 15 to 20 years. (Read more GPS stories.)