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The Planet Neptune is the eighth
planet from the sun. It is also known as the Blue Giant. Neptune is the fourth and outermost of the gas giant planets and also has rings.
Its atmosphere is mostly hydrogen and helium. In Roman mythology Neptune was the
god of the Sea.
Neptune has been visited
by only one spacecraft, Voyager
2 on Aug 25 1989. It
was the last stop in 1989 for the Voyager 2 spacecraft on its grand tour of the
solar system. Recent knowledge has been
gained by ground-based telescopes and the Hubble Space Telepscope.
Due to Pluto's eccentric orbit, Neptune at times
becomes the most distant planet from the Sun for a few years.
Planet Neptune Facts:
Mass: 17.15
Earth-masses
Number of known
satellites: 8
Length of Year:
164.8 Earth-years
Mean Distance from the Sun:
4,500 million kilometers
Mean Orbital Velocity: 5.4 kilometers per second
Length of Day: 16.11 hours, 0.67 Earth-day
Equatorial diameter:
49,500 kilometers
Atmospheric components:
74% hydrogen, 25% helium, 1% methane
Moons of Planet Neptune
Neptune has 8 known moons: Triton, Thalassa,
Naiad, Despina, Galatea, Larissa, Proteus and Nereid
Triton has the coldest temperatures in the
solar system. Voyager observed geysers.
The Great Dark Spot
Voyager 2 observed the Great Dark Spot. Recent
observations made with the Hubble Space Telescope indicate that the Great Dark
Spot no longer exists.
Books:
The Neptune File by
Tom Standage
From Amazon.com,
Amazon.co.uk
Neptune: The Eighth Planet (Countdown to Space) by
Michael D. Cole
From Amazon.com,
Amazon.co.uk
The Planet Neptune Links:
References:
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comments, click on Contact
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