The Planet Neptune
Julia Carnevale
Why the name Neptune?
• Astronomers continued naming the
planets after deities/gods in Roman and
Greek mythology.
• Neptune was the name given to the Greek
god Poseidon, the god of the sea and
earthquakes.
Symbol:
The symbol of Neptune is Neptune’s trident.
The Discovery of Neptune:
• Instead of using a telescope to find
Neptune astronomers used math.
• While scientists were trying to find
Uranus’s orbit they realized that there was
another planet farther out than Uranus.
• They were then able to make
mathematical calculations of where
Neptune should be.
The Discovery of Neptune (cont.):
• Discovered in 1846 by Johann Galle and
Heinrich D’Arrest.
• Triton, Neptune’s largest moon, was
discovered at the same time as the planet.
Distances:
•
•
•
•
Eighth planet.
Farthest planet from the Sun.
Distance from the Sun: 4,945,000,000 km
Distance from Earth: 4,300,000,000 km
Planet Measurements:
• Neptune’s mass is 102.43 g (17.14 times
greater than Earth’s mass).
• Neptune’s volume is 6,254 m3 (57 times
greater than Earth’s volume).
• 1.638 g/cm3
• Neptune would sink in water because its
density is greater than water’s density.
• Neptune’s gravity is 1.14 g (1.19 times
greater than the gravity on Earth).
Orbit and Rotation:
• It takes Neptune about 165 years to orbit
the Sun.
• It takes Neptune about 19.1 hours to
rotate on its own axis.
• In 2011, Neptune completed its first orbit
around the Sun since it was discovered in
1846.
Atmosphere:
• Thick atmosphere.
• Composition: 74% hydrogen, 25% helium,
1% methane.
• Methane gives Neptune its color.
• There are icy clouds, similar to the cirrus
clouds on Earth, and enormous storms on
Neptune.
Temperature:
• Average temperature on Neptune: -184
degrees Celsius (-370 degrees
Fahrenheit)
• Average temperature on Earth: 7 degrees
Celsius (45 degrees Fahrenheit)
• Average temperatures in Florida: 18
degrees Celsius (low) 28 degrees Celsius
(high)
Appearance/Compostion:
• Neptune is a gas giant. Its surface
composition is not rocky or icy, it is water
and melted ice.
• Its internal composition is similar to
Uranus’s with various ices and rocks along
with hydrogen and helium.
• Internal heat source.
Appearance/Composition
(cont.):
• Neptune has many features that other
planets do not. It is a brilliant blue planet
with some white clouds around its surface.
The methane in Neptune’s atmosphere
absorbs red light from the sun but reflects
blue light into space, giving Neptune its
color.
Weather:
• Huge storms or vortices and rapid winds.
• Neptune’s winds are the fastest and
strongest in the solar system reaching
2,000 km/hour (1,200 miles/hour)
• These winds can be 9 times stronger than
Earth’s winds.
Rings:
• Neptune is circled by thin, dark, ringfound
in clumps.
• These rings are composed of rock/dust.
• 6 rings in total.
• They are difficult to find and detect
because the thickness varies throughout
the rings.
• Neptune has 3 distinct rings that are named after
the people who discovered Neptune.
Moons:
• Neptune has 13 moons! Trition, Nereid, Naiad,
Thalassa, Despina, Larissa, Proteus, and
Galatea, plus 5 smaller, unnamed moons.
• There are probably many more moons, but we
have yet to discover them.
• Triton was the first moon to be discovered, and it
is the coldest measured object in our solar
system.
Moons (cont.):
Moons in order of distance from Neptune:
Naiad- NASA’s Voyager 2 mission, 1989
Thalassa- NASA’s Voyager 2 mission, 1989
Despina- NASA’s Voyager 2 mission, 1989
Galatea- NASA’s Voyager 2 mission, 1989
Larissa- NASA’s Voyager 2 mission, 1989
Proteus- NASA’s Voyager 2 mission, 1989
Triton- William Lassell, 1846
Nereid- G. Kuiper, 1949
Water:
• Neptune’s atmosphere consists of water
and melted ice.
• Methane ice clouds.
• Oceans.
What would happen if a human
traveled to Neptune?
• You would freeze because of the extreme
temperatures.
• You would be squashed by the gravity and
the larger mass of the planet.
The Great Dark Spot:
• Huge storm on Neptune that spins
counterclockwise.
• Spiral shaped cirrus clouds around the dark
boundary.
• An Earth-sized hurricane.
• Found in the thick, methane, atmosphere.
• Disappears and reappears occasionally, varying in
sizes and shapes.
• Winds near spot were recorded at 2,400 km/hour
(1,500 m/hour). Strongest winds recorded in our
Solar System.
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<http://www.windows2universe.org/neptune/discover.html>.
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