Increasing perturbations in the motions of Uranus led astronomers to
believe that there were other planets beyond the newly discovered planet. The
first of these was Rev TJ Hussey, the Rector of Heyes, who wrote to the
Astronomer Royal with his idea on 17 November 1834. Two mathematicians, John
Couch Adams (b. 5 June 1819, Lidcot, Laneast, near Launceston; d. 21 January
1892, Cambridge) in England and Urbain Le Verrier (b. 11 March 1811, St Lô;
d. 1877) in France, both worked in parallel on calculating mathematically the
position of an eighth planet. Le Verrier wrote to Johann Galle advising him
where to direct his telescope to discover the new planet, having by now grown
tired of French astronomers' indifference to his views. So it was that in the
early hours of 24 September 1846 (2320 hr GMT, 23rd September), at Berlin
Observatory, Neptune was discovered by Johann Galle and Heinrich D'Arrest,
with Galle's exclamation, "That star is not on the map!"
The new planet was then at 0° 32' Libra, and its progress was tracked until
it set, at 0230 hr LT. It was less than 1° away from the position predicted
independently by both Le Verrier and Adams; a brilliant confirmation of
Newton's laws. Urbain Le Verrier also believed in the existence of the
speculative intra-Mercurial planet Vulcan. Names proposed for the new planet
were Janus, Neptune, Le Verrier and Oceanus.
However, Galileo had sight of the planet on 28 December 1612, and saw that it
had changed position overnight. He did not consider that it could be another
planet, but assumed it to be a moon of Jupiter. Neptune had also previously
been observed, and mistaken for a star, by Joseph Jérôme de Lalande in 1795.
Neptune has an orbital revolution period of 164.79 years, with an eccentricity
of 0.0086, a rotation period of 16hr 3m and is 2,793 million mean miles
distant from the Sun (30.11 AU). In size and mass Neptune is similar to
Uranus, slightly smaller with an equatorial diameter of 31,403 miles, but with
a greater mass. It is 3.85 times the size of Earth, but its mass is 17.148
times as great. . Its axis is inclined by 29.56°, not sharing the
extraordinary tilt of Uranus. Atmospheric temperature is around -220°C.
Neptune has a considerable internal heat-source, unlike Uranus, and has a
bluish appearance due to the existence of methane in its atmosphere, which is
mostly hydrogen. Winds blow at 900 mph at its equator, though the reason for
this is unknown.
Much of what is known of Neptune is as a result of the Voyager 2 probe, which
passed Neptune on 25 August 1989, 3,000 miles from its north pole, which was
then in darkness. Six new inner moons were discovered and the existence of two
complete rings was confirmed. One of these is so thin that no part of it had
been detected before. Only 1% of the volume of space it occupies is filled
with material. The other ring is made up of relatively dense sections - the
parts thought to have been arcs - linked by sparse sections. These
discontinuous sections were expected to disappear within a few months, but
were still evident 15 years later, possibly shepherded by Galatea, one of
Neptune's inner moons. Detailed images of Triton, Neptune's largest moon, were
At the time of the Voyager 2 probe its most prominent feature was a Great Dark
Spot, believed to be a storm system, which is as big in relation to the
planet's size as Jupiter's Great Red Spot. However, the 1995 Hubble space
telescope pictures showed that this Spot had entirely disappeared, and another
had appeared on its Northern Hemisphere. Neptune's surface was found to be
constantly changing, as it experiences hurricane force winds and atmospheric
storms. Its clouds are made of methane crystals rather than water and it also
has a cloud feature nicknamed the Scooter due to its rapid rotation; it darts
around the planet in a jet-stream at speeds of 400 miles per hour. Where
Neptune gets the energy to drive these dynamics is still its mystery.
The sigil for Neptune is derived from the trident of Neptune, although it
can also symbolise the bowl of sacrifice, identified with the chalice of Holy
Grail legend. It is generally interpreted as depicting the semicircle of the
soul, pierced by the cross of matter to create a three-pronged fork, with each
prong symbolising an aspect of human consciousness. These are the physical
body and its senses; the astral body and its desires; and the lower mental
body and its egocentric thoughts. In some variations the cross of matter is
replaced by the circle of spirit. The glyph also resembles the Greek letter
psi, used for psychic phenomenon.
In mythology Neptune is Poseidon, the Greek fertility deity, god of
earthquakes and Lord of Bulls. Since earthquakes bring tidal waves he came to
be associated with ocean depths. The realms of the universe were ruled by
three gods, according to the Greeks. Zeus (Jupiter) ruled the heavens, Hades
(Pluto) the underworld, and Poseidon (Neptune) the oceans. He was also given
the island-continent he named Atlantis, after his eldest son, Atlas. He is
named from Neptunus, the Roman water god. Other sea gods could be connected to
the planet's nature, such as Dionysius, Nereus and Proteus. To the Hindus,
Neptune is Idapati, the Master of the Waters, and it also identifies with
Narayana, the Mover on the Waters, an aspect of the god Vishnu (Jupiter).
Astrologers see Neptune as a higher octave of Venus. It has a dissolving
influence, bestowing nebulousness and confusion, but also imagination,
inspiration and an idealistic and artistic nature. It is concerned not with
the physical world, but with a divine realm. Neptune is closely linked with
the sea, which signifies the ease with which Neptune puts us in contact with
the sea of the unconscious. Despite being named after a male god, Neptune is
regarded as a feminine planet, like Venus, with a right-side brain sphere of
influence. Neptune has become co-ruler with Jupiter of its traditional
rulership of Pisces. Exaltation seems to be ascribed either to Cancer or
Aquarius. It is regarded as strong in Cancer, and in detriment in Virgo. In
esoteric astrology Neptune rules Cancer.
When Neptune was discovered the Spiritualist movement began, hypnotism first
appeared (in 1843) and mesmerism and psychism were revived, and anaesthetics
were first used to render a patient unconscious in 1846. The Communist
Manifesto was published in 1848 as socialism took hold. 1850 saw the first
submarine. In 1875 Madame Helene Blavatsky (b. 31 July 1831 OS, 0302 hr LT,
Ekaterinoslav, now Dnepropetrovska, The Ukraine) founded the Theosophical
Society, which led through its promotion of esoteric teachings to the
resurgence of astrology. Blavatsky had Uranus and Phaethon in opposition in
her natal chart.
Neptune signifies the ideals we strive for; our sense of limitation or
confinement; imagined feelings of guilt; the urge to escape; our visions of
perfection; our flight from reality; listening to music; creative experience;
our attraction to the dream-world; our work with dreams; our fantasies; our
world of make-believe; loving to have the lover in our life as pure fantasy;
the escape from the need to be productive; being in touch with the part of us
that just wants to be.
In mundane astrology Neptune represents universal and utopian tendencies;
collective values; communal, communistic, collectivist living. It can be
politically unrealistic, seeking soft options, "entryism" and fifth
Neptune takes about 165 years to complete a Zodiac cycle. It remains in each
sign for about 14 years, defining each generation with a unique tone.
THE MOONS OF NEPTUNE
Neptune has thirteen known moons. Only two, Triton and Nereid, were known
before Voyager's flypast in 1989, which then brought the total to eight. One, Nereid,
has a highly eccentric one-year orbit, which takes it far away from the planet
making it impossible for Voyager's cameras to get a decent view. It can be
6,021,442 miles from Neptune, but at its closest is only 836,234 miles away.
It was discovered photographically by Gerard Kuiper in 1949. It actually
orbits Neptune in just over 360 days and has a diameter of 149 miles.
One of the six satellites discovered by Voyager, Proteus, is actually
larger than Nereid at 258.5 miles in diameter. It has an orbital period of
1.121 days, and orbits at 73,089 miles from Neptune. All six are too close to
Neptune's surface to be seen from Earth. The other five are Naiad (33.5
miles diameter), the closest at 29,832 miles from the planet, with an orbital
period of 0.296 days; Thelassa (50 miles diameter), 31,075 miles away,
0.312 day orbit; Despina (112 miles diameter), 32,629 miles from
Neptune, 0.333 day orbit; Galatea (93 miles wide), 38,533 miles above
Neptune, 0.429 day orbit; and Larissa (119 miles across), 45,680 miles
away, and an orbital period of 0.544 days.
No more discoveries were made until 2002. With diameters
estimated between 30 to 40 kilometers, the new moonlets were no brighter than 25th magnitude and
carried the temporary designations S/2002 N1, S/2002 N2, and S/2002
N3. Unlike Voyager's finds, they travel in very inclined and elongated
wide orbits that suggest they are the remnants of a collision between a former moon and an
intruding object. S/2003 N1, discovered the following year, travels in a distant and highly irregular orbit that averages
almost 50 million miles from Neptune and takes 26.3 years to complete one revolution.
These irregular moons are thought to be the product of a parent body that collided with Neptune's moon Nereid and were then disturbed in their orbits by the capture of Triton.
By far the most important moon of Neptune is Triton. It was discovered
by William Lassell, a brewer, in his own observatory in Liverpool, only 17
days after the discovery of Neptune itself in 1846. Its density is virtually
the same as Pluto's, and like Pluto it has white polar caps of nitrogen ice,
and a similar atmosphere. It is darker, though, reflecting 38% of light,
compared to Pluto's 55%.
It has a retrograde orbit inclined at an extreme orbital inclination of
159.9° and gets round Neptune in just 5.877 days at a height of 220,510
miles. Colder than anywhere else then known in the Solar System (-236°C) and
smaller (1,681 miles diameter) than expected, it is covered in the southern
hemisphere by rippled light and dark pinkish snow and methane ice, with some
grey frozen lakes from gas and ice geysers, which are still active. Its
terrain is smooth and strange, interspersed with mountain ranges. If there
were crater impacts on the surface, something inexplicable has since smoothed
them away. "Triton is incredible, incredible," a Nasa spokesman
said, "It's out of this world in every sense. It has things we have never
seen on another satellite."
When Voyager 2 sent back images of Triton in February 1992 its surface was
found to contain huge strange ice volcanoes, something quite unique and
unexpected, reinforcing Triton's reputation as the strangest known body in the
Solar System. Triton has a thin atmosphere, of methane and possibly nitrogen,
and is believed to have continents, separated by an ocean of methane and
ethane. It is one of only two moons in the Solar system that has an
Triton is probably not a true satellite of Neptune, but could have been an
asteroid or comet captured by its gravity over 1,000 million years ago,
devouring other moons in its molten state, taking a billion years to solidify.
Its eccentric orbit would gradually have been forced into its present entirely
Triton was the son of Poseidon (Neptune) and Amphitrite, the goddess of the
sea, and is represented as a fish with a human head that makes the oceans roar
by blowing through his shell. Amphitrite was a Nereid, sea-nymphs that were
the daughters of Nereus and Doris.
Triton and Nereid would both influence our emotional nature, utilising the
unconscious to facilitate our emotional mastery.
Last updated 21 April 2005