Planet Neptune: Explore the Farthest Planet From the Sun!

( How big is Neptune? What is Neptune made of? Why is Neptune blue? Read our article and learn curious facts about the outermost planet in the Solar System. )

Neptune is known as the eighth and farthest planet from the Sun, which can’t be seen with the naked eye from the Earth. This distant blue planet has faint rings, numerous moons, and no solid surface. In this article, we’ll tell you more interesting details and curious facts about Neptune. Let’s get started!

Neptune facts

  • Radius: 24,622 km (15,299.4 miles)
  • Mass: 1.02413×10²⁶ kg
  • Aphelion: 4.536 billion km (2.819 billion miles)
  • Perihelion: 4.459 billion km (2.771 billion miles)
  • Average distance from the Earth: 4.5 billion km (2.8 billion miles)
  • Surface temperature: −218 °C to −200 °C (−360 °F to −328 °F)
  • Solar day length: 0.6713 Earth day
  • Sidereal day length: 0.67125 Earth day
  • Year length: 164.8 Earth years
  • Age: 4.503 billion years
  • Named after: Roman god of the sea

When was Neptune discovered?

In 1846, John Couch Adams, a British mathematician and astronomer, determined the position of Neptune, using only mathematics. Around the same time, the French astronomer Urbain Le Verrier calculated the planet’s location independently of Adams. Le Verrier communicated his findings to the German astronomer Johann Gottfried Galle, who identified Neptune in the Berlin Observatory on September 23, 1846, increasing the number of known planets to eight.

How big is Neptune?

Neptune’s size

How many Earths fit in Neptune?

Neptune’s orbit and rotation

How long is a year on Neptune?

How long is a day on Neptune?

How far is Neptune?

How far is Neptune from the Sun?

How far is Neptune from Earth?

How long does it take to get to Neptune?

Missions to Neptune

What is Neptune made of?

Formation of Neptune

Neptune’s structure

What is the surface of Neptune like?

Neptune’s Great Dark Spot

Neptune’s moons

How many moons does Neptune have?

What is Neptune’s largest moon?

Neptune’s rings

How many rings does Neptune have?

What are the rings of Neptune made of?

Upcoming events

September 14: Neptune at opposition

Neptune can never be seen with the naked eye. The ice giant is about five times fainter than the dimmest stars. To observe this distant planet, use a pair of binoculars or a telescope.

December 1: Neptune ends retrograde motion

March 13: Neptune at solar conjunction


Why is Neptune blue?

How cold is Neptune?

Why wont Pluto collide with Neptune?

How did Neptune get its name?

Did you know?

  • Neptune’s largest moon, Triton, is the only large natural satellite in the Solar System that follows a retrograde orbit, moving in the opposite direction of its planet’s rotation.
  • Triton is one of the few geologically active natural satellites in our Solar System: it has active geysers erupting sublimated nitrogen gas.
  • In 2011, Neptune completed its first 165-year orbit since its discovery in 1846.
  • Neptune cannot support life as we know it.

We hope that you’ve discovered something interesting and new about Neptune, the eighth and farthest planet from the Sun. If you liked the article, share it on social media and watch our cartoon about Neptune.

We wish you clear skies and happy observations!

Point your device at the sky and see what stars, constellations, and satellites you are looking at 🌌✨