Vulcan (planet) Guide, Meaning , Facts, Information and Description
Vulcan was the name given to a small planet supposed to exist in an orbit between Mercury and the Sun, in a 19th century hypothesis which is now disproved (or at least superseded).
Vulcan was proposed to explain a small perturbation in Mercury's orbit from the path predicted by classical mechanics, technically called advancing perihelion.
During Mercury's orbit, its perihelion advances by a small amount each orbit. The phenomenon is predicatable by classical mechanics, but the observed value differed from the predicted value by the small amount of 43 arcseconds per century.
This idea and the name "Vulcan" was postulated by the French mathematician Urbain Le Verrier in 1859, closely following his spectacular success in "discovering" the planet Neptune in the same way - using only calculus. Various persons and astronomers around the world attempted to prove the existence of the said planet.
Observing a planet inside the orbit of Mercury is extremely difficult, since the telescope must be pointed very close to the Sun, where the sky is never black. Also, an error in pointing the telescope can result in damage for the optics, and injury to the observer. The huge amount of light present even quite away from the Sun can produce false reflections inside the optics, thus fooling the observer into seeing things that do not exist.
The best strategy for observations is to wait for the planet transit on the Sun disk. A small, round dark spot can be seen moving, as happens regularly with Mercury and Venus.
For half a century, observers tried to find the hypothetical Vulcan. Many false alarms were triggered by round sunspots, that closely resembled a planet transit. During solar eclipses, stars close to the Sun were taken for planets. To reconcile different observations, at some point two planets were postulated. Both James Craig Watson and Lewis Swift believed they had observed two Vulcan-type planets during a solar eclipse.
In 1877 Le Verrier died, still convinced of having discovered another planet. With the loss of its principal proponent, the search for Vulcan cooled down. After many years of searching, astronomers were seriously doubting the planet's existence.
The final act came in 1915, when Einstein's theory of relativity explained the perturbations of Mercury as a mere byproduct of the Sun's gravitational field. His equations predicted slightly different results than classical mechanics, and exactly in the right amount to explain Mercury's actual orbit.
The difference should apply to the orbits of all planets, but only Mercury is so close to the Sun that the effect becomes visible.
However, the search continues for Vulcanoid asteroids which may exist in the region where Vulcan was once thought to exist. None have been found yet and searches have ruled out any such asteroids larger than about 60 km.
A resurge of interest in the theory occurred in the 1960s, and planets called Vulcan began appearing in the science fiction of the time. In the Doctor Who serial entitled The Power of the Daleks the setting is the Earth colony on Vulcan in the early twenty-first century, while the name was used for the fictional home planet of the Vulcan race in Star Trek. According to Gene Roddenberry Vulcan orbits either the star 40 Eridani or Epsilon Eridani. In 1998, scientists indirectly detected a Jupiter-sized planet around Epsilon Eridani. It is not known if this planet is capable of sustaining life or not, but many astronomers point to its highly elliptical orbit as a damaging factor.Argument for Vulcan's existence
The search for Vulcan
Search conclusion
Vulcan in modern fiction