Facts about Neptune

Some interesting facts about Neptune that you may not have heard before:
Discovery of Neptune:
As Neptune is dim and invisible to normal human eye the first observation of Neptune happened only after the invention of telescope. Galileo first observed Neptune in 1612 and then again in 1613 – this is evident from his drawings. But he mistook Neptune for a fixed star as Galileo was not able to notice the motion of the planet through his telescope. Apparently, he doesn’t hold the credit for the discovery of the planet.

Neptune was the first planet to have discovered through mathematical predication rather than astronomical observation. Neptune was discovered on September 23, 1846 by the French mathematician Urbain Le Verrier and the English mathematician John Couch Adams. Actually speaking both the mathematicians predicted the discovery, but it was actually found by the astronomer Johann Gottfried Galle. There were conversies between French and English on who really made the discovery, but the credit has been given to all three and it’s not a controversy anymore.

Farthest Planet:
As the International Astronomical Union in 2006 decided that Pluto isn’t a planet any more Neptune is the farthest planet from Sun. Neptune is 4,503,443,661 km from the Sun – that is 4.5 billion km or 2.8 billion miles approximately.

Voyager 2:
NASA’s Voyager 2 is the only spacecraft to visit Neptune and it took about 12 years for the spacecraft to reach Neptune. During Voyager 2’s flyby, it studied Neptune’s atmosphere, magnetosphere, rings and Neptune’s moons.

Moons of Neptune:
Neptune has about 13 moons and it’s more likely that there are many undiscovered moons in Neptune, since most of the 13 moons were discovered in the past few decades. Triton is the largest moon in Neptune and it was discovered just in 17 days after the discovery of Neptune itself. Triton is the seventh largest moon in the Solar System.

Symbol of Neptune:
The symbol for Neptune is a trident – a weapon associated with the Roman god Neptune.

Neptune Symbol

Neptune Symbol

Diameter of Neptune:
The diameter of Neptune is approximately 49,500 km or 30,447 miles which would make it the 4th largest planet in the Solar System, after Jupiter, Saturn and Uranus.

Temperature of Neptune:
The outer atmosphere of Neptune is one of the coldest places on the Solar System and it can go down to -218 °C. Temperature at the core of the planet can go up to 5,000 °C.

Mass of Neptune:
The mass of Neptune is 1.02 x 1026 kg which equivalent of 17.1 times of Earth’s mass.

Neptune’s fun facts:
Unlike the other moons in the Solar System, Neptune’s moon Triton and Nereid orbit in the opposite direction.

Neptune is bright azure blue in color

The diameter of Neptune is about 3.9 times the diameter of the Earth.

Picture of Neptune:

Picture of Neptune

Picture of Neptune


Hope you enjoyed the Neptune facts in this page.