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
Sun and planet gear rod and thus does not rotate around its own axis. Note that the axle of the planet gear is tied to the axle of the sun gear by a link that freely rotates around the axis of the sun gear and keeps the planet gear engaged with the sun gear but does not contribute to the drive torque. This link appears, at first sight, to be similar to a crank but the drive is not transmitted through it. Thus, it did not contravene the crank patent. Sun and planet gear The sun and planet gear is a method of converting