Scientists working on Galactic Positioning System

Here's the basic idea: Pulsars are neutron stars that spin rapidly and emit a beam of electromagnetic radiation, or radio waves. That beam sweeps over us on the Earth as they rotate. We can effectively use them as galactic lighthouses, since the pulsing rate is so steady—as precise as an atomic clock in some cases.

Using pulsars as a sort of interstellar GPS system is more complex than it seems, though. At the speeds most astronomical objects travel, relativity becomes a factor, making calculations incredibly complex, says MIT's Technology Review.