Vulcan (hypothetical planet) Vulcan (hypothetical planet) Vulcan is a small hypothetical planet that was proposed to exist in an orbit between Mercury and the Sun. Attempting to explain peculiarities of Mercury's orbit, the 19th-century French mathematician Urbain Le Verrier hypothesized that they were the result of another planet, which he named "Vulcan". A number of reputable investigators became involved in the search for Vulcan, and despite occasional claimed observations, no such planet was ever confirmed. Peculiarities in Mercury's orbit have now been explained by Albert Einstein's theory of general relativity. Searches of data gathered by NASA's two "STEREO" spacecraft have failed to find
The empire on which the sun never sets expression, the sun never sets in the Spanish dominions, but ever shines upon one part or other of them : which, to say truly, is a beam of glory [...]". Thomas Urquhart wrote of "that great Don Philippe, Tetrarch of the world, upon whose subjects the sun never sets." In the German dramatist Friedrich Schiller's 1787 play, "Don Carlos", Don Carlos's father, Philip II, says, "" ("I am called / The richest monarch in the Christian world; / The sun in my dominion never sets."). Joseph Fouché recalled Napoleon saying before the Peninsular War, "Reflect that the sun never sets