One of the most curious stories circulating on the Internet, is the existence of an artificial satellite orbiting the planet every 15 or 20 years, known as "the black knight".

The story goes back to 1899. Around this time, Tesla moved to a laboratory in Colorado Springs to start his experiments with high voltage and electric field measurements. During the eight months he was there, he spent part of his time to developing small signals and receivers measure the ability of a vertical antenna. During his tests, Tesla caught a periodic signal coming from somewhere in space.