30 Interesting Facts About Neptune

Last updated on May 3rd, 2019

18. Exploration by spacecraft: just one mission has been sent to Neptune in 1989. Maybe because of its long distance from the Earth or due to the lack of interest of the scientific community because of the non-availability of conditions to sustain human life on Neptune.

19. How hot? the average surface temperature of Neptune is minus 214 degree Celsius.

20. One day on the planet: the length of a day on Neptune is 16 hours.

facts about Neptune: Gas Giant Interiors
Gas Giant Interiors. Image credit – Lunar and Planetary Institute

21. Uranus vs Neptune: Uranus is bigger than Neptune.

22. Neptune vs Earth – size comparison: it would take 60 Earth’s to completely occupy the space available on Neptune.

23. Supersonic winds: winds as fast as 1200 MPH blow on Neptune and these winds have blown away the Great Dark Spot on Neptune.

24. Wind speed comparison: Winds on Neptune can be three times faster than that on  Jupiter and nine times faster than that on Earth. And scientists are amazed as to why the winds on the planet blow so fast.

25. A Monster Dark Spot: Great Dark Spot in the southern atmosphere of Neptune was first recorded by Voyager 2 in 1989. Wind speeds upward of 1500 miles per hour were recorded during this storm. However, the storm only lasted for 5 years, because when in 1994, the Hubble Space Telescope was used to view the dark Spot, the Dark Spot was not there anymore.

26. Neptune vs Earth – gravitational force: Neptune’s gravitational force is only 17% stronger than that of Earth. Thus, Neptune is the only planet in the solar system that has Earth-like gravity.

27. Coldest of all: Neptune also has the credit of being the coldest planet in our Solar System. The temperature on the planet can get as low as minus 221 °C (The lowest natural temperature ever directly recorded at ground level on Earth is minus 89.2 °C, which was at the Soviet Vostok Station in Antarctica.)

28. Maiden orbit: since its discovery in 1946, Neptune completed its first orbit around the Sun in 2011.

29. Planet “Nine”: now a team of scientists lead by astronomer Mike Brown have announced in 2016 that they have some evidence of the existence of another planet in the solar system which they have nicknamed “planet Nine”. This planet is supposed to have 10 times the mass of Earth and an orbit which is 20 times farther than the sun on average than Neptune.

30. Latest moon: Neptune’s fourteenth (14th) moon was discovered on July 1, 2013, during a fresh analysis of the images collected by the Hubble Space Telescope. The moon was spotted nearly 150 times in the images that were collected during 2004 and 2009. Scientists estimate that the moon is just 12 miles wide. 

Neptune – Quick facts

Date of Discovery23 September 1846
Discovered byUrbain Le Verrier, John Couch Adams, Johann Galle
Orbit size around Sun4,498,396,441 km
Mean Orbit Velocity19,566 km/h
Equatorial inclination28.3 degrees
Equatorial Circumference154,704.6 km
Volume62,525,703,987,421 cubic kilometer
Mass102,410,000,000,000,000,000,000,000 kg
Density1.638 gram per centimeter cube
Surface Area7,618,272,763 kilometer square
Surface Gravity11.15 meter per second square
Escape Velocity84,816 kilometer per hour
Effective Temperature-214 °C
Atmospheric ConstituentsHydrogen, Helium, Methane
Known Moons14
Known Rings6
Largest moonTriton
Names of moonsTriton, Proteus, Naiad, Thalassa, Despina, Galatea, Larissa, Nereid, Sao, Halimede, Neso, Psmathe, Laomedeia, S/2004 N 1
Missions to NeptuneJust one: Voyager 2 in 1989.
Characteristic colorBlue