1 of 21

NEPTUNE

2 of 21

NEPTUNE

In Roman and Greek (Poseidon) mythologies, Neptune is the god of the sea and of the underworld.

He is a son of Saturn and so a brother of Jupiter. Neptune wields a trident as a weapon against his enemies. As creator of the horse, he is the patron god of horse racing.

3 of 21

NEPTUNE

Neptune is an average of 4.5x109 km from the Sun and has an orbital period of 165 years. It rotates once every 16 hours.

4 of 21

NEPTUNE

Along with Uranus, Neptune one of two “ice” giant planets in our solar system.

They are theorized to have a rocky core surrounded by a mantle of “ices”. Above the mantle some sources suggest a liquid hydrogen /helium layer, others report it as a gas.

5 of 21

NEPTUNE

17x Earth’s mass, but a little smaller than Uranus. Compare this to Uranus’ 14.5 Earth masses. A greater mass in a smaller volume means that Neptune is more dense that Uranus.

6 of 21

NEPTUNE

Deep blue color. The blue is caused by methane in the upper atmosphere which reflects blue light. This also gives Uranus its blue color but the difference between the two is unknown.

7 of 21

NEPTUNE

Neptune has sustained winds of over 2000km/hr. Prevailing theory is that cold temperatures make for less friction which allows the wind speeds to build.

8 of 21

NEPTUNE

With less energy in the outer solar system, Uranus has fewer and smaller storms. However, Neptune’s strong winds counter this tendency and so has relatively strong storms as seen here.

9 of 21

NEPTUNE

Neptune has a magnetic field which is off center (like Uranus’). Speculation is that the icy mantle is causing this in both ice giants. There’s no strong correlation, but these are the only two planets that have icy mantles and exhibit off center magnetic fields.

10 of 21

NEPTUNE

It has 3 main rings; 2 narrow and one broader. The rings seem to be clumpy, with dark and light sections in each.

11 of 21

NEPTUNE

12 of 21

NEPTUNE

Neptune has 12 14 known moons.

13 of 21

NEPTUNE’S MOON TRITON

Its largest moon is Triton with a diameter of 2700km.

Its retrograde orbit suggests that it is a captured Kuiper Belt object.

What does retrograde mean?

14 of 21

NEPTUNE’S MOON TRITON

Note the similar appearance of Triton and Pluto. Pluto is a Kuiper Belt object.

15 of 21

NEPTUNE’S MOON TRITON

Triton’s surface has water ice, methane ice, and nitrogen ice. Its surface is very flat with few craters. Which means……

…which means that it has been renewed; likely by cryovolcanoes. Active nitrogen geysers have been seen erupting on its surface.

16 of 21

NEPTUNE

Neptune was discovered in 1846 on purpose. The orbit of Uranus was always observed to be off a bit from where it should have been according to calculations.

17 of 21

NEPTUNE

Mathematician Urbain Le Verrier predicted that this was due to a new, undiscovered planet. He used math to predict where it could be found.

18 of 21

NEPTUNE

Neptune was found within 1° of his prediction on the very next night after his prediction.�

Neptune is the only planet to have been found with math….so far.

19 of 21

20 of 21

21 of 21