- 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.

Old Rock Day

This day is completely dedicated to collect different rocks. To make this day more exciting, you can go on a small adventurous trip to hunt for old fossils and rocks or you can simply do different things with rocks at home. Every year on January 7th, people are encouraged to go and dig in their...

Houseplant Appreciation Day

The holidays are over. The decorations have been put away for another year. The house looks a little plain, a little drab. In the greyishness of January, your eye catches something in the corner of the room. Why, it's a houseplant! Funny, but with all of the holiday hubabuloo, you've all but...

Cold Sophie

For centuries, farmers and gardeners in Germany and some other mid-European countries are mostly afraid of the “Ice Saints,” which come usually May 11 through 15. The Ice Saints are named after their patrons. May 11 is St. Mamertus, May 12 is St. Pankratius, May 13 is St....

Nature Photography Day

This day was designated by North American Nature Photography Association (NANPA) to promote the enjoyment of nature photography, and to explain how images have been used to advance the cause of conservation and protect plants, wildlife, and landscapes locally and worldwide. In 2006, NANPA...

Meteor Day

The word “meteor” refers to a visible streak of light that is produced by debris falling to the Earth from space. We also call this beautiful phenomenon a “shooting star” or “falling star.” The tradition of wishing upon a shooting star can be traced all the way back to 127 AD. Ptolemy,...

International Mountain Day

International Mountain Day, held each year on 11 December, was established by the UN General Assembly in 2003. The UN encourages events to be organized at all levels that day on behalf of sustainable development in mountains. Healthy mountain forests are crucial to the ecological health of...

Download KeepIn Calendar

Enjoy the interesting stories even on your phone or tablet