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, 1989Thalassa- NASA’s Voyager 2 mission, 1989Despina- NASA’s Voyager 2 mission, 1989Galatea- NASA’s Voyager 2 mission, 1989Larissa- NASA’s Voyager 2 mission, 1989Proteus- NASA’s Voyager 2 mission, 1989Triton- 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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