Planets · Ice giant

Neptune

4.5 billion km from the Sun · Light crosses it in 0.16 seconds

Across

49,244 km

Vs Earth

0.35× Jupiter

Mass

17 Earths

Open Neptune in Cosmic Scale

About

Neptune was found with mathematics before anyone looked: astronomers noticed Uranus was being tugged off course, calculated where the culprit must be, and pointed a telescope there in 1846. It is an ice giant with the fiercest winds in the Solar System.

Its winds are the fastest in the Solar System, over 2,000 km/h.

At a glance

Year	165 years
Day	16 hours
Winds	Up to 2,100 km/h
Moons	16 known

Did you know

1. It has completed only one orbit since its discovery, in 2011.
2. Its blue colour comes from methane absorbing red light — though its true shade is paler than the famous Voyager images suggest.
3. Voyager 2, in 1989, is the only spacecraft ever to visit.

Real photos

• Neptune's auroras, seen for the first time by Webb, 2025 (in cyan) — NASA, ESA, CSA, STScI, Heidi Hammel (AURA), Henrik Melin (Northumbria University), Leigh Fletcher (University of Leicester), Stefanie Milam (NASA-GSFC) (CC BY 4.0) · source
• Neptune from Voyager 2, 1989 — NASA/JPL · source
• Neptune and its faint rings from the James Webb Space Telescope, 2022 — NASA, ESA, CSA, and STScI (CC BY 4.0) · source