I published this post some years ago (archived version), but for unilateral decision of the online publisher, it is deleted, so I decide to recover it now.
We all known the story of the little green men: in 1967 Jocelyn Bell and Antony Hewish discovered a strange, regular cosmic signal, a periodic bep. They consulted Fred Hoyle, astronomers and sci-fi writer, and he understood that the signal was emitted by a neutrons' star, a pulsar. An italian research team, composed by Matteo Luca Ruggiero, Emiliano Capolongo, Angelo Tartaglia, published the following paper, Pulsars as celestial beacons to detect the motion of the Earth (arXiv). In their paper, researchers propose to apply some relativistic mathematical tools to calculate Earth position using pulsars signals.