* Astronomy

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RE: Neptune

Blobrana · L

Average Distance From Sun:	4,504,300,000 Km
Diameter:	49,000 KM
Mass:	1.7135e+01 x Earth Standard
Gravity:	1.05 x Earth Standard
Atmosphere:	Very Cold Gases
Moon:	13
Axis tilt	29 degrees.
Neptune Year:	164.79 Earth Years
Neptune Day:	16.11 Earth hours

Neptune is the eighth and last planet from the Sun. Neptune's magnetic field is tilted 47 degrees from the planet's rotation axis, and is offset at least 0.55 radii

Neptune

has three narrow orbital rings enclosed in a disc of dust that may reach down to the Neptunian cloud tops. Neptune has two named moons (Triton and Nereid), and six more discovered by the Voyager 2 probe in 1989, of which 1989 N1 (diameter 418 km/260 mi) is larger than Nereid.

Neptune

is an 8th magnitude object visible in binoculars and in 2006 the planet resides in Capricornus, the Sea Goat. It arrives at opposition on August 11, 2006.

Neptune

was located on the 23 September 1846 by Galle and D'Arrest after calculations by John Couch Adams and Urbain Jean-Joseph Le Verrier had predicted its existence on the basis that another body must be disturbing the orbit of Uranus. The cameras of Voyager 2, which passed Neptune in Aug 1989, revealed a wide variety of cloud features.
for large colourmap

Notable

6-year animation

among these were bright polar collars and broad bands in different shades of blue girdling Neptune's southern hemisphere.The blue colouring results from the absorption of red light by the methane in the atmosphere. Another cloud feature is an Earth-sized oval storm cloud, which has been named the Great Dark Spot, and has been likened to the Great Red Spot on Jupiter.
Above and around it, cirrus-type clouds of frozen methane are forming and taking shape, with winds of up to 2,400 kph. Neptune is believed to have a central rocky core covered by a layer of ice.

Mystery solved.

Neptune

The interior structures of Uranus and Neptune are radically different from what was previously assumed about these cold, distant planets. Even though they are gas giants, they are different from Jupiter and Saturn.
These two outer planets may have only a thin layer of metallic convecting fluid just under the gassy hydrogen surface. This would explain what causes the magnetic field to be tipped on its side compared to the rotational axis and also explain the "quadrupole" effect. Their magnetic fields are tipped over midway to the equator, and there are two north and two south poles, as if the field were produced by two bar magnets.

The Hubble Space Telescope
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Neptune Methane Band

captures the distant blue-green world, Neptune, and its satellites in this portrait. Astronomers used Hubbles assortment of filters to pinpoint high altitude clouds floating above the methane rich atmosphere.

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Neptune Enhanced Colour

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Neptune Natural Colour

Hubble Space Telescope

Images have been assembled into a time-lapse movie revealing the orbital motion of the satellites. The icy moons seen in this view are Proteus (the brightest), Larissa, Despina, and Galatea. Neptune had 13 moons at last count. neptune moons

In Roman mythology, Larsissa and Despina were Neptuness daughters.

Neptune Moons
Moon	#	Radius (km)	Mass (kg)	Distance (km)	Period (days)	Discoverer	Date
Naiad	III	29	?	48,000	0.294	Voyager 2	1989
Thalassa	IV	40	?	50,000	0.311	Voyager 2	1989
Despina	V	74	?	52,500	0.335	Voyager 2	1989
Galatea	VI	79	?	62,000	0.429	Voyager 2	1989
Larissa	VII	104x89	?	73,600	0.555	Voyager 2	1989
Proteus	VIII	200	?	117,600	1.122	Voyager 2	1989
Triton	I	1,350	2.14e+22	354,800	5.88	W. Lassell	1846
Nereid	II	170	?	5,513,400	360.1	G. Kuiper	1949
S2002 N1		20	?	15686000	1874.8	M. Holman	2002
S2002 N2		20	?	22337190	2925.6	M. Holman	2002
S2002 N3		20	?	22613200	2980.4	M. Holman	2002
S/2003 N1 Psamathe	X	19		46738000	9136.1		2003
S/2002 N4		60		47279670	9007.1		2002

This timelapse movie

of Neptune was assembled from combining the Hubble Space Telescope images taken over a 15-hour period. The movie shows a dynamic atmosphere and captures the fleeting orbits of Neptunes satellites . The natural colour and enhanced colour views of Neptune were assembled from images in 14 different coloured filters. This allows atmospheric features to be seen above Neptune's methane haze, which gives the planet its blue-green colour.
The animation has four sections, each one corresponding to approximately one rotation of Neptune.

(1.64Mb mpeg movie) The first section shows Neptune and its largest satellite Triton, which is about as large as our moon. Probably a captured Kuiper Belt object, Triton orbits Neptune in a "backwards" or retrograde path relative to the other major satellites, and opposite to Neptune's rotation. The view is close to what a human eye would see looking through the Hubble Space Telescope.
The second scene zooms in on Neptune, and the colours have been enhanced to better show the subtle detail of clouds in Neptune's atmosphere.
The third scene has the spectral region of light changed from the visible to special methane bands in the near infrared. Most of Neptune's atmosphere becomes very dark, except for high-altitude clouds.
The fourth scene traces the satellite orbits. Four of the small, inner satellites are visible orbiting Neptune. Dutifully obeying Kepler's laws of planetary motion, the outer moons take longer to revolve around Neptune than the inner ones. From outside to inside, these satellites are Proteus, Larissa, Galatea, and Despina. These moons are so faint that only the longest Hubble exposures can capture them.
The outermost layers of Neptune's thick atmosphere do not rotate like a solid body. The polar atmospheric regions finish a full rotation in about 15 hours, while the equatorial regions lag behind, taking more than 18 hours for a complete circuit of the planet.

Rings of Neptune
Name	Distance*	Width	Thickness	Mass	Albedo
1989N3R	41,900 km	15 km	?	?	low
1989N2R	53,200 km	15 km	?	?	low
1989N4R	53,200 km	5,800 km	?	?	low
1989N1R	62,930 km	< 50 km	?	?	low

Blobrana · L

Neptune sounds

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A new theory from an Australian researcher contends that master astronomer Galileo may have discovered Neptune, 234 years before its official discovery.
Professor David Jamieson, Head of the School of Physics has claimed that, buried its annotations in notebooks from 400 years ago, is evidence that Galileo had discovered the planet we now call Neptune.
Prof Jamieson has had his findings published in the journal Australian Physics and presented his theory at the 2009 July Lectures in Physics program at the University of Melbourne last week.
According to Galileo's notebooks, he had been following an unknown star during the years 1612 and 1613 while observing the moons of Jupiter.

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Simple incompetence has led more than a few scientists to miss major discoveries. When the 19th-century English mathematician John Adams claimed to have worked out that a new planet would be found in the constellation Aquarius, a simple search of the area would have proved him right. Unfortunately, the job was given to a Cambridge University astronomer named James Challis, who actually saw the planet in 1846 but failed to recognise it. Barely a month later, astronomers in Germany made no such mistake and were duly hailed as the discoverers of Neptune.
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Hubble Makes Movie of Neptune's Dynamic Atmosphere

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The deep interior of Neptune, Uranus and Earth may contain some solid ice. Through first-principle molecular dynamics simulations, Lawrence Livermore National Laboratory scientists, together with University of California, Davis collaborators, used a two-phase approach to determine the melting temperature of ice VII (a high-pressure phase of ice) in pressures ranging from 100,000 to 500,000 atmospheres.

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Neptune is at Opposition on the 15th August 2008.
The planet will reach a magnitude of 7.8, which is bright enough for moderate binoculars.

Opposition is the point when Neptune appears opposite to the Sun in the sky. On the 15 August the planet will rise as the Sun sets and will set as the Sun rises providing an entire night of observation. At Opposition the planet comes physically closest (distance to earth: 29.025 AU) to the Earth, and consequently is one of the best times for viewing the planet.
The moon is new on the 16th and will not interfere with the event.

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Position(2000): RA=21h40m48s Dec=-14°16.0'

Neptune is located in the constellation Capricornus, the Sea Goat, until the year 2010.

Blobrana · L

Asteroid 2007 VL305

Blobrana · L

RE: Neptune