Wikipedia: Vulcan

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The Flat Earth Theory is a myth used to impugn pre-modern civilization, especially that of the Middle Ages in Europe. The allegation is that people in some past era believed that the world was flat and that those sailing too far would go off the edge. This legendary belief-system is frequently ascribed to the Catholic Church, especially in the time of Christopher Columbus. The attack is often validated by being linked to the genuine controversy over the geocentric and heliocentric models of the cosmos (see History of astronomy, Ptolemy (2), and Copernicus. Both sides in that debate had no doubt that the world was a sphere: the diameter of the world had been calculated quite accurately by Eratosthenes? in the 3rd century BC. The objection to Columbus' expedition was that Columbus disregarded this measurement and gravely underestimated the length of the voyage west - he would inevitably run out of supplies and fresh water before he could reach India. This objection was correct, but Columbus found a sponsor anyway, and found another continent instead of a short cut to India.

There is no doubt people once thought the world was flat. Early Greek philosophy portrayed the world as a circular disk floating in the ocean. According to Greek Myth, Atlas was punished by being required to hold up the world. (See Hercules.) Some historians have taught that sailors as late as the renaissance era feared falling off the edge of the earth if they ventured too far West of the Straits of Gibraltor.

According to historian [Jeffrey Burton Russell]?, the Flat Earth Theory is a myth used to impugn pre-modern civilization, especially that of the Middle Ages in Europe. The allegation is that people in some past era believed that the world was flat and that those sailing too far would go off the edge. This legendary belief-system is frequently ascribed to the Catholic Church, especially in the time of Christopher Columbus. The attack is often validated by being linked to the genuine controversy over the geocentric and heliocentric models of the cosmos (see History of astronomy, Ptolemy (2), and Copernicus. Both sides in that debate had no doubt that the world was a sphere: the diameter of the world had been calculated quite accurately by Eratosthenes? in the 3rd century BC. The objection to Columbus' expedition was that Columbus disregarded this measurement and gravely underestimated the length of the voyage west - he would inevitably run out of supplies and fresh water before he could reach India. This objection was correct, but Columbus found a sponsor anyway, and found another continent instead of a short cut to India.

Vulcan in Roman Mythology is the son of Jupiter and Juno, and husband of Maia? and Venus. He was god of fire and volcanoes, and the manufacturer of art, arms and armor for gods and heroes. His smithy was believed to be situated underneath [Mount Aetna]? in Sicily. At the Vulcanalia festival, which was held on August 23, fish and small animals were thrown into a fire. Vulcan's analogue in Greek mythology is the god Hephaestus?.

At one point it was suspected that there existed a small planet that orbited between Mercury and the Sun, proposed to explain perturbations in Mercury's orbit from the path predicted by Classical Mechanics. This hypothetical planet was known as Vulcan. Albert Einstein's Theory of Relativity later explained these perturbations without the need for a third body, however, and so the possible existence of the planet Vulcan was discounted.

The name was later reused for a fictional planet in Star Trek.

The Vulcan was a British Royal Air Force jet propelled bomber. Vulcans were capable of delivering nuclear weapons. A Vulcan featured in the James Bond film Thunderball.

The GAU-4 20mm Vulcan (with two models, designated M61A1 and M61A2) is a hydraulically driven, 6 barreled, rotary action, air cooled, electrically fired [gatling gun]? with selectable rates of fire of either 4000 or 6000 rounds per minute. It is mounted on F-104?, F-105?, later models of the F-106?, F-111?, F-4?, B-58?, F-15, F-16, F-22?, F-14? and F/A-18? aircraft, and is used for short-range air-to-air combat with secondary usefulness in strafing ground targets. It was developed in 1946 by the United States Army Ordnance Research and Development Service, and manufactured by General Electric. Each of the gun's six barrels fires only once during each revolution of the barrel cluster; the six rotating barrels contribute to long weapon life by minimizing barrel erosion and heat generation. The gun's rate of fire, essentially 100 rounds per second, gives the pilot a shot density that will enable a "kill" when fired in one-second bursts. The weapon's current contractor is [General Dynamics Armament Systems]?.

External link: http://www.fas.org/man/dod-101/sys/ac/equip/m61.htm