FIND IT TONIGHT · BANGKOK
Neptune in numbers
- 3.9 × Earth
- Width
- 16 h 6 min
- One day
- 2,000 km/h
- Wind speeds, the fastest in the Solar System.
- 165 years
- One orbit. It finished its first lap since discovery in 2011.
- 16
- Known moons. The biggest, Triton, orbits backwards.
WORTH KNOWING
Found with maths before anyone saw it.
Astronomers noticed Uranus drifting off its predicted path and worked out where an unseen planet must be. Neptune was found there in 1846.
You need a telescope to see it: even at its brightest it is far too faint for the naked eye.
Who has been there
- 1989Voyager 2The only spacecraft to visit, so far.