Neptune
Overview
Neptune, an ice giant and the eighth planet, is the farthest planet in the solar system. We came to know of its presence only in 1846. Neptune is not visible to the naked eye.
To give a brief history on what led to its discovery: In 1821, astronomers had found a problem with the orbit of Uranus. Its orbit did not match with their calculations. The mismatch made them conclude that there must be an unknown world that must be perturbing the orbit of the nearby Uranus.
In 1846, the French astronomer Urbain Le Verrier made an exact mathematical prediction on where the 8th planet could be found. Soon, the German astronomer Johann Galle found it using the Berlin Observatory’s telescope.
Neptune was named after the Roman god of the sea.
Interesting Facts
Moons/Rings: Neptune has 14 known moons. Triton is the largest of all the moons. It circles Neptune in a direction opposite to Neptune’s rotation (retrograde orbit) suggesting that it could be a captured object. The ring system of Neptune has five known rings.
Size: Neptune and Uranus are almost identical in size – Neptune’s radius is 24,622 kilometers while Uranus’ radius is 25,362 kilometers. Both are almost four times the size of our Earth. (Radius of Earth is 6371 kilometers.)
Atmosphere: Neptune’s atmosphere consists of mostly hydrogen and helium with a small quantity of methane too.
Orbit: Neptune orbits the Sun at an average distance of about 4.5 billion kilometers which is almost 30 times the distance between Earth and the Sun. Sunlight takes 4 hours to travel from the Sun to Neptune.
Day and Year: Neptune takes 16 hours to spin on its axis and 165 earth years to orbit the Sun.
Sources:
- The Cambridge Guide to the Solar System by Kenneth R. Lang, Cambridge University Press.