3. is the 8th planet from the
Sun and the fourth largest (by
diameter).
is smaller in diameter but
larger in mass than Uranus.
NEPTUNE
4. orbit: 4,504,000,000 km (30.06 AU)
from Sun
diameter: 49,532 km (equatorial)
mass: 1.0247e26 kg
PLANET PROFILE
5. History of Neptune
In Roman mythology,
NEPTUNE - the god of the sea among the Romans. He was not
a very powerful god, and little is known of his origin. When he
was first introduced in Rome, he already had all the
characteristics of the Greek Poseidon. Despite the fact that his
cult grew after his equation with Poseidon, Neptune was far
less popular among sailors than Poseidon was among the
Greek mariners.
Neptune was held in much higher regard as Neptune Equester,
the god and patron of horse-racing and horses. One of temples
was located near the Circus Flaminius, one of the larger trace-
tracks. Another sanctuary was in the Campus Martius (25 BCE)
were the Neptunalia was celebrated on July 23. The trident is
Neptune's attribute.
6. Poseidon from Milos, 2nd century BC (National
Archaeological Museum of Athens)
Abode Mount Olympus, or the Sea
Symbol Trident, fish, dolphin, horse
and bull
Consort Amphitrite
Parents Cronus and Rhea
Siblings Hades, Demeter, Hestia,He
ra, Zeus
Children Theseus,Triton,Polyphemu
s, Belus,Agenor, Neleus,Atl
as
Roman equivalent Neptune
7. Neptune was held in much higher regard as
Neptune Equester, the god and patron of horse-
racing and horses. One of temples was located
near the Circus Flaminius, one of the larger trace-
tracks. Another sanctuary was in the Campus
Martius (25 BCE) were the Neptunalia was
celebrated on July 23. The trident is Neptune's
attribute.
8. RESEARCHERS:
Galle, Johann Gottfried 1812-1910
German astronomer who, with Heinrich Louis d'Arrest, made
the first observation of Neptune based on calculations by Le Verrier.
Though Galle was the first to observe Neptune, its discovery is usually
credited to Adams (who made an earlier calculation) and LeVerrier.
d'Arrest, Heinrich Louis
Danish astronomer who assisted Galle with the first
observations of Neptune. After receiving its predicted position
from Le Verrier, Galle and d'Arrest began searching. With Galle at the
eyepiece and d'Arrest reading the chart, they scanned the sky and
checked that each star seen was actually on the chart. Just a few
minutes after their search began, d'Arrest cried out, "That star is not
on the map!" and earned his place in the history books
9. RESEARCHERS:
Adams, John Couch 1819-1892
English astronomer and mathematician who, at the age of 24, was
the first person to predict the position of a planetary mass beyond Uranus.
But, unfortunately, Adams did not publish his prediction.Galle confirmed the
existence of Neptune based on independent calculations done by LeVerrier.
LeVerrier, Urbain Jean Joseph 1811-1877
French mathematician whose prediction of the position of an
undiscovered planet (Neptune) that caused perturbations in the orbit
of Uranus was the first to be confirmed (by Galle) though Adams had made a
similar but unpublished prediction some months earlier.
10. Galileo Galilei 1564-1642
Italian astronomer and physicist. The first to use a
telescope to study the stars. Discoverer of the first moons
of an extraterrestrial body (see above). Galileo was an
outspoken supporter of Copernicus'sheliocentric theory.
In reaction to Galileo, the Church declared it heresy to
teach that the Earth MOVED and silenced him.
RESEARCHERS:
11. Neptune's elliptical, oval-shaped orbit keeps the planet an
average distance from the sun of almost 2.8 billion miles
(4.5 billion kilometers), or roughly 30 times as far away as
Earth, making it invisible to the naked eye. Neptune goes
around the sun once roughly every 165 Earth years,
and completed its first orbit, since being discovered, in
2011.
Every 248 years, Pluto moves inside Neptune's orbit for 20
years or so, during which time it is closer to the sun than
Neptune. Nevertheless, Neptune remains the farthest
planet from the sun, since Pluto was reclassified as a
dwarf planet in 2006.
Orbital characteristics
12. Atmospheric composition (by volume): hydrogen, 80 percent;
helium, 19.0 percent; methane, 1.5 percent
Magnetic field: Roughly 27 times more powerful than Earth's
Composition:The overall composition of Neptune is, by mass,
thought to be about 25 percent rock, 60 to 70 percent ice, and 5
to 15 percent hydrogen and helium, according toTristan Guillot,
author of "Interiors of Giant Planets Inside and Outside the Solar
System" in the journal Science.
Internal structure: Mantle of water, ammonia and methane ices;
Core of iron and magnesium-silicate
Composition & structure
13. Average distance from the sun: 2,795,084,800
miles (4,498,252,900 km). By comparison: 30.069
times farther than Earth
Perihelion (closest approach to the sun):
2,771,087,000 miles (4,459,630,000 km). By
comparison: 29.820 times that of Earth
Aphelion (farthest distance from the sun):
2,819,080,000 miles (4,536,870,000 km). By
comparison: 30.326 times that of Earth
Orbit & rotation
14. Neptune has 14 known moons, named after
lesser sea gods and nymphs from Greek
mythology. The largest by far is Triton, whose
discovery on Oct. 10, 1846, was in a sense
enabled by beer — amateur astronomer William
Lassell used the fortune he made as a brewer to
finance his telescopes.
Neptune's moons
15. Triton is the only spherical moon of Neptune — the
planet's other 13 moons are irregularly shaped. It is also
unique in being the only large moon in the solar system to
circle its planet in a direction opposite to its planet's
rotation — this "retrograde orbit" suggests that Triton may
once have been a dwarf planet that Neptune captured
rather than forming in place, according to NASA.
Neptune's gravity is dragging Triton closer to the planet,
meaning that millions of years from now, Triton will come
close enough for gravitational forces to rip it apart.
16. Triton is extremely cold, with temperatures
on its surface reaching about minus 391
degrees F (minus 235 degrees C), making it
one of the coldest places in the solar system.
Nevertheless, Voyager 2 detected geysers
spewing icy matter upward more than 5 miles
(8 km), showing its interior appears warm.
Scientists are investigating the possibility of
a subsurface ocean on the icy moon. In
2010, seasons were discovered onTriton.
17. In 2013, scientists working with SETI caught sight of Neptune's "lost"
moon of Naiad using data from the Hubble Space Telescope. The 62-
mile-wide (100 km) moon has remained unseen since Voyager 2
discovered it in 1989.
Also in 2013, scientists using the Hubble Space Telescope found the
14th moon, dubbed S/2004 N 1. It is Neptune's smallest moon and is
just 11 miles (18 km) wide. It got its temporary name because it is the
first satellite (S) of Neptune (N) to be found from images taken in
2004, according to NASA.
The rings of Neptune
Neptune's unusual rings are not uniform, but possess bright thick
clumps of dust called arcs. The rings are thought to be relatively
young and short-lived. Earth-based observations announced in 2005
found that Neptune's rings are apparently far more unstable than
previously thought, with some dwindling away rapidly, according to
an article in the journal Icarus.
18. NASA's Voyager 2 satellite was the first and as yet only
spacecraft to visit Neptune on Aug. 25, 1989. The satellite
discovered Neptune's rings and six of the planet's moons —
Despina, Galatea, Larissa, Naiad, Proteus and Thalassa. An
international team of astronomers relying on ground
telescopes announced the discovery of five new moons
orbiting Neptune in 2003.
Research & exploration
19. Neptune is generally thought to have
formed with the initial buildup of a solid core
followed by the capture of surrounding hydrogen
and helium gas in the nebula surrounding the
early sun. In this model, proto-Neptune formed
over the course of 1 to 10 million years.
Formation of Neptune
