Astronomy · Planets

Neptune

The deep-blue, windy ice giant at the edge.

Order from Sun: Eighth planet
Type: Ice giant
Color: Deep blue
Notable moon: Triton, which orbits backward

NASA/JPL · NASA media (public domain)

Gallery

Neptune — real observation image. — Neptune
This contrast enhanced color picture of Neptune was acquired by NASA Voyager 2 on Aug.
1999
NASA/JPL · NASA media (public domain)
Source archive ↗

The outermost planet

Neptune is the eighth and farthest major planet from the Sun. A deep-blue ice giant, it is similar in size and makeup to Uranus and lies far out in the cold outer Solar System.

A stormy atmosphere

Despite its great distance from the Sun, Neptune has an active, dynamic atmosphere with some of the fastest winds measured on any planet, along with large dark storm systems.

Discovery and Triton

Neptune was the first planet found through mathematical prediction rather than chance observation. Its largest moon, Triton, orbits in the opposite direction to Neptune's rotation, a strong hint that it was captured from elsewhere.

Knowledge connections

How this connects across Asteria Star — scientific, cultural, and astrological links are kept separate.

Scientific connections

Part ofSolar System
Parent ofTriton
Parent ofNereid
Parent ofProteus
Associated with2:3 resonance with Neptune
Associated with1:1 resonance with Neptune
Associated withVoyager 2 Flies Past Neptune
Associated withThe Solar System in 3D

Observational connections

Observed byJohann Galle

Mission connections

Target ofVoyager 2Voyager 2 is the only spacecraft to visit Uranus and Neptune.

Related toThe Prediction and Discovery of Neptune

Space mission
Voyager 2
Voyager 2 is a NASA space probe launched in 1977 and the only spacecraft to have flown past all four giant planets: Jupiter, Saturn, Uranus, and Neptune.

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Fast facts

Order from Sun: Eighth planet
Type: Ice giant
Color: Deep blue
Notable moon: Triton, which orbits backward

Key points

The farthest of the eight planets from the Sun.
An ice giant with some of the strongest winds in the Solar System.
Its large moon Triton orbits in the 'wrong' direction, suggesting it was captured.

Data & provenance

Stable ID: planet:neptune
Type: Planet
Domain: Scientific connections
Relationships: 11
Graph version: 1.0.0

Dataset membership

Planets

Open data

In the graph export: graph.json · graph.jsonld

Planned API: GET /api/v0/entities/planet:neptune

Scientific quality

Complete

Reviewed2 sourcesv1.0.0

7 of 7 applicable dimensions complete

Description: Complete
Source coverage: Complete
Relationship coverage: Complete
Review coverage: Complete
Citation coverage: Complete
Image coverage: Complete
Timeline coverage: Complete

Scientific entity. Dimensions that cannot apply to this object are excluded rather than counted as gaps. See the evidence framework and authority dashboard.

Provenance & sources

review 2026.1

Asteria Scientific Review Process · verification: sourced · accurate

High evidenceconfirmed
Neptune is the eighth and most distant known planet, an ice giant with the strongest sustained winds measured in the Solar System.
Source: NASA (NSSDCA) — NASA Planetary Fact Sheet · Public domain (US Government work)
- NASA Planetary Fact Sheet, Planetary Fact Sheet

Reviewed by the internal Asteria Scientific Review Process — not an external institutional review. See the evidence framework and authority dashboard.

Scientific citations

Real, source-backed references — primary papers first, then datasets and institutional sources. Formatted through the citation engine; nothing is fabricated.

DatasetApproximate Positions of the Planets

NASA Jet Propulsion Laboratory (Caltech)

Cite (APA / BibTeX)

NASA Jet Propulsion Laboratory (Caltech) (n.d.). Approximate Positions of the Planets. NASA Jet Propulsion Laboratory (Caltech). https://ssd.jpl.nasa.gov/planets/approx_pos.html

@misc{cite:jpl-approx-positions,
  title        = {Approximate Positions of the Planets},
  organization = {NASA Jet Propulsion Laboratory (Caltech)},
  year         = {n.d.},
  url          = {https://ssd.jpl.nasa.gov/planets/approx_pos.html},
  note         = {Public-domain Keplerian orbital elements and rates (Standish) — the method behind the computed planet positions, rise/set, and visibility.}
}

DatasetNeptune Fact Sheet

NASA Goddard — NSSDCA

Cite (APA / BibTeX)

NASA Goddard — NSSDCA (n.d.). Neptune Fact Sheet. NASA Goddard — NSSDCA. https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact.html

@misc{cite:factsheet-planet-neptune,
  title        = {Neptune Fact Sheet},
  organization = {NASA Goddard — NSSDCA},
  year         = {n.d.},
  url          = {https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact.html},
  note         = {Physical and orbital parameters for Neptune.}
}

Institutional pageNeptune — NASA Solar System Exploration

NASA

Cite (APA / BibTeX)

NASA (n.d.). Neptune — NASA Solar System Exploration. NASA. https://science.nasa.gov/

@misc{cite:nasa-planet-neptune,
  title        = {Neptune — NASA Solar System Exploration},
  organization = {NASA},
  year         = {n.d.},
  url          = {https://science.nasa.gov/},
  note         = {NASA overview of Neptune.}
}

Sources & references

The primary and reference sources this topic draws on.

NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
NASA JPLJet Propulsion Laboratory / Solar System Dynamics
Orbital data, ephemerides, and small-body parameters for planets, asteroids, and comets.

Neptune

Gallery

The outermost planet

A stormy atmosphere

Discovery and Triton

Knowledge connections

Scientific connections

Observational connections

Mission connections

Related

Uranus

Pluto

Mercury

Venus

Voyager 2

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Neptune

Gallery

The outermost planet

A stormy atmosphere

Discovery and Triton

Knowledge connections

Scientific connections

Observational connections

Mission connections

Related

Related entries

Uranus

Pluto

Mercury

Venus

Related missions

Voyager 2

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