Neptune: Discovery, Atmosphere, Interior, Rings, Moons

Neptune

Eighth planet from the Sun, discovered in 1846.

Distance from the Sun

Approximately 2,792,000,000 miles.

Size

30,710 miles in diameter.

Orbital period

164.79 years.

Rotational period

16.11 hours.

Number of Satellites

14 known moons.

Neptune's atmosphere

Composed of hydrogen 80%, helium 18%, methane 2%, and trace amounts of other gases.

Ammonia

Cannot exist in the gaseous state in Neptune's atmosphere due to low temperature.

Color of Neptune's atmosphere

Absorbs red light, resulting in a deep blue color.

Dark Spots

Two major dark features on Neptune's atmosphere, thought to be holes in the methane cloud deck.

Hubble Space Telescope

Used to observe Neptune and revealed the disappearance of the Great Dark Spot.

Scooter

A small white cloud on Neptune's atmosphere with changing shape and mysterious nature.

Neptune's internal structure

Resembles that of Uranus, with a larger proportion of rocky materials.

Neptune's magnetic field

Weakest among the Jovian planets, offset and tilted to the axis of rotation.

Internal Heat

Neptune radiates more energy than it receives from the Sun due to its continuing contraction.

Discovery of Neptune's rings

First detected through stellar occultation observations, later revealed by Voyager 2. evidence suggested that the rings were incomplete arcs that extended only part of the way around the planet

Structure of Neptune's rings

Five dark, narrow rings with prominent concentrations of material within the Adams Ring.

Composition of Neptune's rings

Methane-rich ice particles, mostly dust-sized.

Origin of Neptune's rings

Thought to result from the collisional fragmentation of inner moons.

Triton

Neptune's major moon, with characteristics similar to Pluto and other Kuiper Belt Objects.

Orbit of Triton

Unusual retrograde orbit, synchronous rotation, and tilted orbital plane.

Atmosphere of Triton

Very tenuous and transparent, primarily composed of nitrogen with small amounts of methane and possibly carbon monoxide.

Surface of Triton

Frozen nitrogen, methane, carbon monoxide, carbon dioxide, and water-ice.

Terrains on Triton

Vast, rugged surface with cantaloupe terrain, large smooth terrain, and walled plains called planitia.

Polar Ice Caps on Triton

Highly reflective caps of frozen nitrogen and methane at the poles.

Dark Streaks on Triton

Deposits by geysers of nitrogen gas mixed with dust, created by solar heating.

Interior of Triton

Differentiated into a solid core, mantle, and crust, with a possible subterranean ocean.

Minor Moons of Neptune

13 irregularly shaped moons, possibly captured asteroids or fragments from collisions.

Proteus

Neptune's major moon with a heavily cratered surface and no signs of geologic activity.