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Neptune Discovery
Galileo's was the who observed
Neptune on December 27, 1612, and again on January
27, 1613; on both occasions Galileo mistook Neptune
for a fixed star when it appeared very close (in
conjunction) to Jupiter in the night sky. Believing
it to be a fixed star, he cannot be ascribed with
its discovery. At the time Galileo first observed
Neptune on December 28, 1612, it was stationary
in the sky since it had just turned retrograde
that very day; because it was stationary in the
sky and only beginning the planet's yearly retrograde
cycle, its motion was far too slight to reveal
with the naked eye, even with the help that a
telescope provided. Had Neptune been moving at
its regular/average speed when Galileo first observed
it in 1612 and 1613, he would have most likely
realized that it was a planet and not a fixed
star because of Neptune's relatively rapid normal
motion along the ecliptic compared to the extremely
slow motion of any random fixed star found in
the night sky.
In 1821, Alexis Bouvard
published astronomical tables of the orbit
of Uranus. Consequent observations exposed
significant deviations from the tables,
leading Bouvard to hypothesise some perturbing
body. In 1843, John Couch Adams calculated
the orbit of an eighth planet that would
account for Uranus' motion. He sent his
calculations to Sir George Airy, who asked
Adams for a clarification; Adams began to
draft a reply but never sent it.
In 1846, Urbain Le Verrier,
autonomously of Adams, produced his own
calculations but also experienced difficulties
in encouraging any zeal in his compatriots.
However, in the same year, John Herschel
started to champion the mathematical approach
and persuaded James Challis to seek for
the planet.
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After much delay, Challis began
his averse search in July 1846. However, in the
mean time, Le Verrier had convinced Johann Gottfried
Galle to search for the planet. Though still a
student at the Berlin Observatory, Heinrich d'Arrest
suggested that a recently drawn chart of the sky,
in the region of Le Verrier's predicted location,
could be compared with the current sky to search
for the displacement characteristic of a planet,
as opposed to a stationary star. Neptune was discovered
that very night, September 23, 1846, within 1°
of where Le Verrier had predicted it to be, and
about 10° from Adams' prediction. Challis
later realised that he had observed the planet
twice in August, failing to recognize due to his
casual approach to the work.
In the result of the discovery,
there was much nationalistic opposition between
the French and the British over who had priority
and who should get credit for the discovery. Ultimately
an international consent emerged that both Le
Verrier and Adams jointly deserved credit. However,
the issue is now being re-evaluated by historians
with the rediscovery in 1998 of the "Neptune
papers" , which actually had been misappropriated
by astronomer Olin Eggen for nearly three decades
and were not rediscovered (in his possession)
until immediately after his death. After reviewing
the documents, some historians now suggest that
Adams did not in fact deserve equal credit with
Le Verrier.
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Naming
Of Neptune
Soon after its discovery, Neptune was referred
to simply as "the planet exterior to Uranus"
or as "Le Verrier's planet". The first
suggestion for a name came from Galle. He proposed
the name Janus. In England, Challis put forth
the name Oceanus, particularly apt for a nautical
people. In France, Arago suggested that the new
planet be called Leverrier, a suggestion which
was met with stiff resistance outside France.
French almanacs swiftly reintroduced the name
Herschel for Uranus and Leverrier for the new
planet.
In the meantime, on separate
and sovereign occasions, Adams suggested altering
the name Georgian to Uranus, while Leverrier suggested
Neptune for the new planet. Struve came out in
accord of that name on December 29, 1846, to the
Saint Petersburg Academy of Sciences [3]. Soon
Neptune became internationally accepted nomenclature.
In Roman mythology Neptune was the god of the
sea, identified with the Greek Poseidon. The claim
for a mythological name seemed to be in keeping
with the nomenclature of the other planets, all
of which, except Uranus, were named in ancient
times.
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