Hypothetical Planet Vulcan

Planet Vulcan Presumed to Be Orbiting Around the Sun

In the present model of the solar system, the planet Mercury seems to be the closest to the Sun. Planet Vulcan was the planned planet presumed to be orbiting around the Sun in the area between Mercury and Sun. Based on the calculation of Le Verrier, the proposal of planet was done to explain the peculiarities in the orbit of Mercury and the French mathematician, Le Verrier was the one who had predicted the existence of the planet Neptune by calculations to clarify the orbit of Uranus.

He assumed that the peculiarities in the orbit of Mercury could be owing to some unknown planet orbiting between the Sun and Mercury. Numerous investigators were involved in the study of the new planet Vulcan though no such planet seemed to be found. Peculiarities in orbit of Mercury had been clarified by the Theory of General Relativity of Albert Einstein. Besides Mercury, asteroid 2007 EB with a semi-major axis of 0.55 AU has the smallest known semi-major axis revolving around the Sun. Director of the Paris Observatory, Francois Arago, had suggested to the French mathematician Urbain Le Verrier, in 1840, to work on the topic of orbital motion of the planet Mercury around the Sun.

Purpose – Recommend a Model for Planet Mercury

The purpose of the study was to recommend a model for the planet Mercury based on the laws of motion and gravitation of Sir Isaac Newton.Towards 1843, Le Verrier had published his provisional theory on the topic that would be tested at the time of transit of Mercury across the face of the Sun in 1843. However his theory failed in matching the observation.

 He then published a thorough study of Mercury’s motion again. The consistency of the study meant that any deviation from prediction would be the result of some unknown factor and there would still be some discrepancy. During the motion of Mercury, its perihelion progresses by a small amount each orbit, technically known as perihelion precession. The value observed differs from the value predicted by Classical mechanics by around 43 arc seconds per century. Le Verrier assumed that the unwarranted precession could be described with the presence of a small planet within the orbit of Mercury, proposing the name `Vulcan’ for this object.

Astronomer Denies the Passage of any Planet over the Sun

Lescarbault, a country doctor at Orgeres, France had reported Le Verrier that he had seen an object which was a size of a planet cross the disc of the Sun on March 26, 1859. Lee Verrier had been to Orgeres and had interviewed the amateur astronomer regarding the unidentified planetary object. Lescarbault had estimated the duration of the transit as 1 hour, 17 minutes and 9 seconds.

He was completely convinced from the observation of Lescarbault and believed that he had seen the transit of an earlier unknown planet. He announced the discovery of Vulcan on January 2, 1860, at a meeting of the Academic des Sciences in Paris. Apparently not all accepted the discovery of Vulcan and renowned French astronomer, Emmanuel and Liais claimed that they had been studying the surface of the sun through a telescope which as powerful as the telescope of Lescarbault at the same time when reported by him. Liais has strongly denied the passage of any planet over the Sun during the time indicated.