- September 23 -

Neptune Discovered

Neptune is the eighth and farthest planet from the Sun in the Solar System. It is the fourth-largest planet by diameter and the third-largest by mass. Among the gaseous planets in the solar system, Neptune is the most dense. Neptune is 17 times the mass of Earth and is slightly more massive than...

Neptune Discovered

Neptune is the eighth and farthest planet from the Sun in the Solar System. It is the fourth-largest planet by diameter and the third-largest by mass. Among the gaseous planets in the solar system, Neptune is the most dense. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times the mass of Earth but not as dense. On average, Neptune orbits the Sun at a distance of 30.1 AU, approximately 30 times the Earth–Sun distance. Named for the Roman god of the sea, its astronomical symbol is ?, a stylised version of the god Neptune's trident.

Neptune is invisible to the naked eye as it is too dim. Its apparent magnitude is never brighter than 7.7. Therefore, the first observations of Neptune were only possible after the invention of the telescope. There is evidence that Neptune was seen and recorded by Galileo Galilei in 1613, Jérôme Lalande in 1795 and John Herschel in 1830, but none is known to have recognized it as a planet at the time. These pre-discovery observations were important in accurately determining the orbit of Neptune. Neptune would appear prominently even in early telescopes so other pre-discovery observation records are likely.

Neptune was subsequently observed on 23 September 1846 by Johann Galle within a degree of the position predicted by Urbain Le Verrier, and its largest moon, Triton, was discovered shortly thereafter, though none of the planet's remaining 13 moons were located telescopically until the 20th century. Neptune has been visited by only one spacecraft, Voyager 2, which flew by the planet on 25 August 1989.

The planet Neptune was mathematically predicted before it was directly observed. With a prediction by Urbain Le Verrier, telescopic observations confirming the existence of a major planet were made on the night of September 23–24, 1846, at the Berlin Observatory, by astronomer Johann Gottfried Galle (assisted by Heinrich Louis d'Arrest), working from Le Verrier's calculations. It was a sensational moment of 19th century science and dramatic confirmation of Newtonian gravitational theory. In François Arago's apt phrase, Le Verrier had discovered a planet 'with the point of his pen'.
In retrospect, after it was discovered it turned out it had been observed many times before but not recognized, and there were others who made various calculations about its location, which did not lead to its observation. By 1846 the planet Uranus had completed nearly one full orbit since its discovery by William Herschel in 1781, and astronomers had detected a series of irregularities in its path which could not be entirely explained by Newton's law of gravitation. These irregularities could, however, be resolved if the gravity of a farther, unknown planet were disturbing its path around the Sun. In 1845 astronomers Urbain Le Verrier in Paris and John Couch Adams in Cambridge separately began calculations to determine the nature and position of such a planet. Unfortunately, Le Verrier's triumph also led to a tense international dispute over priority, as, shortly after the discovery, George Airy, at the time British Astronomer Royal, announced that Adams had also predicted the discovery of the planet. Nevertheless, the Royal Society awarded Le Verrier the Copley medal in 1846 for his achievement, without mention of Adams.
The discovery of Neptune led to the discovery of its moon Triton by William Lassell just seventeen days later.
Source:
http://en.wikipedia.org/wiki/Neptune
http://en.wikipedia.org/wiki/Discovery_of_Neptune

Categories:

You may also like...

Interesting events from Nature category.

Plant a Flower Day

Plant a Flower Day is a day to get a little dirt under your fingernails. Take a few minutes to plant a flower today. Gardening is a great hobby. It's enjoyed by millions of people, old and young alike. Its a hobby that virtually everyone can participate in, regardless of age, and health....

International Day of Forests

The International Day of Forests and the Tree is held annually on 21 March to raise awareness of sustainable management, conservation and sustainable development of all types of forests for the benefit of current and future generations. The United Nations General Assembly adopted resolution...

World Hydrography Day

Every year, the 21 June is taken as an opportunity to increase public awareness of the vital role that hydrography plays in everyone’s life. Hydrographic data provides a wealth of useful information to scientists conducting many types of research and hydrographers contribute to a healthy...

Neptune Discovered

Neptune is the eighth and farthest planet from the Sun in the Solar System. It is the fourth-largest planet by diameter and the third-largest by mass. Among the gaseous planets in the solar system, Neptune is the most dense. Neptune is 17 times the mass of Earth and is slightly more massive than...

International Day for Preventing the Exploitation of the Environment in War and Armed Conflict

The United Nations’ (UN) International Day for Preventing the Exploitation of the Environment in War and Armed Conflict is annually held on November 6. It aims to educate people about the damaging effects of war and armed conflict on the environment. History On 5 November...

Poinsettia Day

December 12th is Poinsettia Day celebrating the beautiful plant we've come to associate with Christmas. The date marks the death of Joel Roberts Poinsett, an American botanist, physician and Minister to Mexico who in 1828 sent cuttings of the plant he'd discovered in Southern Mexico to his home in...

Download KeepIn Calendar

Enjoy the interesting stories even on your phone or tablet