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
Return to the Lost Planet on the development of this genre in Israel. The plot follows on precisely from "The Lost Planet". A previous expedition to Hesikos, the wandering 'lost planet' which is now within a few days flight of Earth, has crash-landed, and Dr Lachlan McKinnon (its organiser), Professor Hermanoff and American engineer Spike Stranahan are marooned. McKinnon's colleagues must build and launch a spaceship from their Scottish base to travel to Hesikos, but to construct the ship they must obtain the expert assistance of Dr Andrieff, a scientist and engineer, who risks exile from his Eastern European country by so doing. The crew,