Vulcan was the name given to a small planet proposed to exist in an orbit between Mercury and the Sun, in a 19th century hypothesis which has now been superseded by Albert Einstein's theory of general relativity. A planet is generally considered to be a relatively large mass of accreted matter in orbit around a star that is not a star itself. ... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... Atmospheric characteristics Atmospheric pressure trace Potassium 31. ... The Sun is the star at the center of Earths solar system. ... Albert Einstein, photographed by Oren J. Turner in 1947. ... It has been suggested that Einsteins theory of gravitation be merged into this article or section. ...

Argument for Vulcan's existence

Vulcan was proposed to explain a small perturbation in Mercury's orbit from the path predicted by classical mechanics, technically called advancing perihelion. Classical mechanics is a branch of physics which studies the deterministic motion of objects. ...

During Mercury's orbit, its perihelion advances by a small amount each orbit. The phenomenon is predicted by classical mechanics, but the observed value differed from the predicted value by the small amount of 43 arcseconds per century. This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ...

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. Leonhard Euler is considered by many people to be one of the greatest mathematicians of all time A mathematician is a person whose primary area of study and research is mathematics. ... Urbain Le Verrier. ... Atmospheric characteristics Surface pressure ≫100 MPa Hydrogen - H2 80% ±3. ...

The search for Vulcan

In December 1859, Le Verrier received a letter from a French physician and amateur astronomer called Edmond Modeste Lescarbault, who claimed to have witnessed a transit of the hypothetical planet earlier in the year. Le Verrier took the next train to the village of Orgères-en-Beauce, some 70 kilometres southwest of Paris, where Lescarbault had built himself a small observatory. Le Verrier arrived unannounced and proceeded to interrogate the shy physician. Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 The word transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at... The Eiffel Tower, the international symbol of the city, with the skyscrapers of La Défense business district 5 km/ 3 mi behind. ...

Lescarbault described in detail how, on 26 March 1859, he noticed a small black dot on the face of the Sun, which he was studying with his modest 3.75 inch (95 mm) refractor. Thinking it to be a sunspot, Lescarbault was not at first surprised, but after some time had passed he realized that it was moving. Having observed the transit of Mercury in 1845, he assumed that he what he was observing was another transit, but of a previously undiscovered body. He took some hasty measurements of its position and direction of motion, and using an old clock and a pendulum with which he took his patients’ pulse, he estimated the duration of the transit at 1 hour, 17 minutes and 9 seconds. March 26 is the 85th day of the year in the Gregorian Calendar (86th in leap years). ... 1859 is a common year starting on Saturday. ... The Sun is the star at the center of Earths solar system. ... The 50 cm refractor at Nice Observatory. ... Atmospheric characteristics Atmospheric pressure trace Potassium 31. ...

Le Verrier was satisfied that Lescarbault had indeed witnessed the transit of a previously unknown planet. On 2 January 1860 he announced the discovery of Vulcan to a meeting of the Académie des Sciences in Paris. Lescarbault, for his part, was awarded the Légion d'honneur and invited to appear before numerous learned societies. January 2 is the second day of the year in the Gregorian calendar. ... 1860 is the leap year starting on Sunday. ... The French Academy of Sciences (Académie des sciences) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. ... Knights badge of the Legion of Honour The Légion dhonneur (Legion of Honor (AmE) or Legion of Honour (ComE)) is an Order of Chivalry first established by Napoléon Bonaparte, First Consul of the French Republic, on May 19, 1802. ...

Not everyone accepted the veracity of Lescarbault’s "discovery", however. An eminent French astronomer, Emmanuel Liais, who was working for the Brazilian government in Rio de Janeiro in 1859, claimed to have been studying the surface of the Sun with a telescope twice as powerful as Lescarbault’s at the very moment that Lescarbault said he witnessed his mysterious transit. Liais, therefore, was "in a condition to deny, in the most positive manner, the passage of a planet over the sun at the time indicated" (Popular Science, Volume 13, pages 732-735, 1878). Emmanuel Liais (1826–1900) was a French astronomer, botanist and explorer who spent many years in Brazil. ... Ipanema beach, in the South Zone, immortalised by Tom Jobim and Vinicius de Morais song The Girl from Ipanema Rio de Janeiro (meaning River of January in Portuguese), pron. ...

Based on Lescarbault’s "transit", Le Verrier computed Vulcan’s orbit: it revolved about the Sun in a nearly circular orbit at a distance of 21 million kilometres, or 0.14 astronomical units. The period of revolution was 19 days and 17 hours, and the orbit was inclined to the ecliptic by 12 degrees and 10 minutes. As seen from the Earth, Vulcan’s greatest elongation from the Sun was 8 degrees. The astronomical unit (AU or au or a. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ... This diagram shows the elongations (or angle) of the Earths position from the Sun. ...

Numerous reports — most of them unreliable — began to reach Le Verrier from other amateurs who claimed to have witnessed unexplained transits. Some of these reports referred to observations made many years earlier, and many could not be properly dated. Nevertheless, Le Verrier continued to tinker with Vulcan’s orbital parameters as each new reported sighting reached him. He frequently announced dates of future Vulcan transits, and when these failed to materialize, he tinkered with the parameters some more.

Among the earlier alleged observers of Vulcan, the following are the most noteworthy (Astronomical Register, 1869):

• Gruithuisen, on 26 June 1819, reported seeing "two small spots … on the Sun, round, black and unequal in size"
• Pastorff, on 23 October 1822, 24 and 25 July 1823, six times in 1834, on 18 October 1836, 1 November 1836 and on 16 February 1837, also claimed to have seen two spots; the larger was 3 arcseconds across, and the smaller 1.25 arcseconds.

Shortly after eight o’clock on the morning of 29 January 1860, F A R Russell and three other people witnessed an alleged transit of an intra-Mercurial planet from London (Nature, 5 October 1876). An American observer, Richard Covington, many years later claimed to have seen a well defined black spot progress across the Sun’s disk around 1860, when he was stationed in Washington Territory (Scientific American, 25 November 1876). June 26 is the 177th day of the year (178th in leap years) in the Gregorian Calendar, with 188 days remaining. ... 1819 common year starting on Friday (see link for calendar). ... October 23 is the 296th day of the year (297th in leap years) in the Gregorian Calendar, with 69 days remaining. ... 1822 (MDCCCXXII) was a common year starting on Tuesday (see link for calendar) of the Gregorian calendar (or a common year starting on Thursday of the 12-day-slower Julian calendar). ... (Redirected from 24 July) July 24 is the 205th day (206th in leap years) of the year in the Gregorian Calendar, with 160 days remaining. ... July 25 is the 206th day (207th in leap years) of the year in the Gregorian calendar, with 159 days remaining. ... 1823 was a common year starting on Wednesday (see link for calendar). ... October 18 is the 291st day of the year (292nd in Leap years). ... Charles Darwin 1836 was a leap year starting on Friday (see link for calendar). ... November 1 is the 305th day of the year (306th in leap years) in the Gregorian Calendar, with 60 days remaining. ... Charles Darwin 1836 was a leap year starting on Friday (see link for calendar). ... February 16 is the 47th day of the year in the Gregorian Calendar. ... | Queen Victoria, Queen of the United Kingdom (1837 - 1901) 1837 was a common year starting on Sunday (see link for calendar). ... January 29 is the 29th day of the year in the Gregorian calendar. ... 1860 is the leap year starting on Sunday. ... October 5 is the 278th day of the year (279th in Leap years). ... 1876 (MDCCCLXXVI) is a leap year starting on Saturday. ... Categories: Historical stubs | Washington history | U.S. historical regions and territories ... November 25 is the 329th (in leap years the 330th) day of the year in the Gregorian calendar. ... 1876 (MDCCCLXXVI) is a leap year starting on Saturday. ...

No successful observations of Vulcan were made in 1861. Then, on the morning of 22 March 1862, between eight and nine o’clock, another amateur astronomer, a Mr Lummis of Manchester, England, witnessed a transit. A colleague whom he alerted also witnessed the event. Based on these gentlemen’s reports, two French astronomers, Benjamin Valz and Rodolphe Radau, independently calculated the object’s orbital period, Valz deriving a figure of 17 days and 13 hours, and Radau a figure of 19 days and 22 hours. 22 March is the 81st day of the year in the Gregorian Calendar (82nd in Leap years). ... 1862 was a common year starting on Wednesday (see link for calendar). ... Jean Elias Benjamin Valz (May 27, 1787 – April 22, 1867) was a French astronomer. ... Jean Charles Rodolphe Radau (January 22, 1835 – December 21, 1911) was an astronomer and mathematician who worked in Paris at the Revue des deux Mondes for most of his life. ...

On 8 May 1865 another French astronomer, Aristide Coumbrary observed an unexpected transit from Constantinople. May 8 is the 128th day of the year in the Gregorian Calendar (129th in leap years). ... 1865 (MDCCCLXV) is a common year starting on Sunday. ... Constantinople[1] was the name of the modern-day city of Ä°stanbul, Turkey over the centuries that it served as the second capital of the unified Roman Empire, and after its division into East and West, of the Eastern Roman Empire, also known as the Byzantine Empire (from the city...

Between 1866 and 1878 no reliable observations of the hypothetical planet were made. Then, during the total solar eclipse of 29 June 1878, two experienced astronomers, Professor James Craig Watson, director of the Ann Arbor Observatory in Michigan, and Lewis Swift, an amateur from Rochester, New York, both claimed to have seen a Vulcan-type planet close to the Sun. Watson, observing from Separation, Wyoming, placed the planet about 2.5 degrees southwest of the Sun, and estimated its magnitude at 4.5. Swift, who was observing the eclipse from a location near Denver, Colorado, saw what he took to be an intra-Mercurial planet about 3 degrees southwest of the Sun. He estimated its brightness to be the same as that of Theta Cancri, a fifth-magnitude star which was also visible during totality, about 6 or 7 minutes from the "planet". Theta Cancri and the planet were very nearly in line with the centre of the Sun. June 29 is the 180th day of the year (181st in leap years) in the Gregorian Calendar, with 185 days remaining. ... 1878 (MDCCCLXXVIII) was a common year starting on Tuesday (see link for calendar). ... James Craig Watson (January 28, 1838 – November 22, 1880) was a Canadian-American astronomer born in the village of Fingal in Ontario, Canada. ... Official language(s) None (English, de-facto) Capital Largest city Lansing Detroit Area  - Total   - Width   - Length    - % water  - Latitude  - Longitude Ranked 10th 102,384 sq mi  265,172 km² 239 miles  385 km 491 miles  790 km 41. ... Lewis A. Swift (February 29, 1820 – January 5, 1913) was an American astronomer. ... A portion of Rochesters skyline, looking north along the Genesee River from the Ford Street Bridge. ... // Headline text HEY!! HOW ARE YOU ALL?? Its nice of you to come read this page. ... This article is the current U.S. Collaboration of the Week. ...

Watson and Swift were excellent observers. Watson had already discovered more than twenty asteroids, while Swift had several comets named after him. Both described the colour of their hypothetical intra-Mercurial planet as "red". Watson reported that it had a definite disk – unlike stars, which appear in telescopes as mere points of light – and that its phase indicated that it was approaching superior conjunction. An asteroid is a small, solid object in our Solar System, orbiting the Sun. ... Comet Hale-Bopp For other uses, see Comet (disambiguation). ... Conjunction is a term used in positional astronomy and astrology. ...

These are merely the more reliable observations of alleged intra-Mercurial planets. For half a century or more, many other observers tried to find the hypothetical Vulcan. Many false alarms were triggered by round sunspots, that closely resembled planets in transit. During solar eclipses, stars close to the Sun were mistaken for planets. At one point, to reconcile different observations, at least two intra-Mercurial planets were postulated. A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings and intense magnetic activity, which inhibits convection, forming areas of low surface temperature. ... ECLiPSe is a constraint logic programming language developed in IC-Parc. ...

Search conclusion

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. Albert Einstein, photographed by Oren J. Turner in 1947. ... Wikisource has original text related to this article: Relativity: The Special and General Theory Albert Einsteins theory of relativity, or simply relativity, refers specifically to two theories: special relativity and general relativity. ...

The difference applies to the orbits of all planets, but the magnitude of the effect diminishes as one gets farther out from the Sun. Also, Mercury's fairly eccentric orbit makes it much easier to detect the perihelion shift than is the case for the nearly circular orbits of Venus and Earth. Adjective Venusian or (rarely) Cytherean (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ... Earth is the third planet in the solar system. ...

Vulcan revived

Observing a planet inside the orbit of Mercury would be 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. 50 cm refracting telescope at Nice Observatory. ...

The best strategy for observations would be to wait for the planet's transit of the Sun's disk. A small, round dark spot might be seen moving, as happens regularly with Mercury and Venus. Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 The word transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at... (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ...

In 1915, when Einstein successfully explained the apparent anomaly in Mercury's orbit, most astronomers abandoned the search for Vulcan. A few, however, remained convinced that not all the alleged observations of Vulcan were bogus. Among these was Henry C Courten, of Dowling College, New York. Studying photographic plates of the 1970 eclipse of the Sun, he and his associates detected several objects which appeared to be in orbits close to the Sun (Miami Herald, 15 June 1970). Even accounting for artifacts, Courten felt that at least seven of the objects were real. The appearance of some of these objects was confirmed by another observer in North Carolina, while a third observer in Virginia saw one of them. June 15 is the 166th day of the year in the Gregorian calendar (167th in leap years), with 199 days remaining. ... 1970 (MCMLXX) was a common year starting on Thursday (the link is to a full 1970 calendar). ... Official language(s) English Capital Largest city Raleigh Charlotte Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 28th 139,509 km² 805 km 240 km 9. ... Official language(s) English Capital Richmond Largest city Virginia Beach Area  - Total  - Width  - Length  - % water  - Latitude  - Longitude Ranked 35th 110,862 km² 320 km 690 km 7. ...

Courten believed that an intra-Mercurial planetoid between 130 and 800 kilometres in diameter was orbiting the Sun at a distance of about 0.1 astronomical unit. Other images on his eclipse plates led him to postulate the existence of an asteroid belt between Mercury and the Sun. Planetoid (meaning planet-like) is an old synonym of asteroid. ... The astronomical unit (AU or au or a. ...

None of these claims has ever been substantiated after more than thirty years of observation. It has been surmised, however, that some of these objects - and other alleged intra-Mercurial planets - may exist, being nothing more than previously unknown comets or small asteroids. Today, the search continues for these so-called Vulcanoid asteroids, which are thought to exist in the region where Vulcan was once sought. None have been found yet and searches have ruled out any such asteroids larger than about 60 km. Vulcanoids are hypothetical asteroids that may orbit in a dynamically stable zone between 0. ...

Vulcan in modern fiction

Ross Rocklynne wrote a short story, "At the Center of Gravity", about two individuals trapped inside a hollow Vulcan. The story was published in the June 1936 issue of Astounding magazine and republished in the 1963 anthology Exploring Other Worlds (ISBN 0020231105). Ross Rocklynne (born Ross Louis Rocklin February 21, 1913 in Ohio) (died October 29, 1988) was a science fiction author in the Golden Age of Science Fiction. ...

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 21st century, while the name was used for the fictional home planet of Mr. Spock and 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. Doctor Who is a long-running British science fiction television programme produced by the BBC about a mysterious time-travelling adventurer known only as The Doctor, who explores time and space with his companions, fighting evil. ... The Power of the Daleks is a serial in the British science fiction television series Doctor Who, which was first broadcast in six weekly parts from November 5 to December 10, 1966. ... Spock, commonly called Mr. ... Vulcans are a humanoid species in the fictional Star Trek universe who reside on the planet Vulcan and are noted for their attempt to live by reason and logic, with no interference from emotion. ... Star Trek collectively refers to an American science-fiction franchise spanning six unique television series (which comprise 726 episodes) and ten feature films, in addition to hundreds of novels, computer and video games, fan stories, and other works of fiction — all of which are set within the same fictional universe... Gene Roddenberry, the creator of Star Trek Eugene Wesley Roddenberry (August 19, 1921 – October 24, 1991 Born in El Paso, Texas) was an American scriptwriter and producer. ... 40 Eridani (also known as Omicron 2 Eridani, or Keid, from the Arabic word qayd (egg) shells) is a triple star system less than 16. ... Epsilon Eridani (ε Eri / ε Eridani) is a main-sequence K2 class star in the constellation of Eridanus. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ...

References

• Richard Baum and William Sheeham. In Search of Planet Vulcan: The Ghost in Newton's Clockwork Machine. 1997. ISBN 0-306-45567-6.

See also

• Nemesis (star)
• Planet X

Nemesis is the name given to a hypothetical red dwarf star or brown dwarf, orbiting the Sun at a distance of about 50,000 to 100,000 AU, somewhat beyond the Oort cloud. ... Planet X was a large hypothetical planet orbiting beyond the orbit of Neptune. ...

External links

• The Planet that Wasn't by Isaac Asimov
• Vulcan, the intra-Mercurial planet