Gonggong
What is Gonggong?
Dwarf planets· Diameter 1,230 km. The fifth-largest known body beyond Neptune — unusually red, slowly rotating every 22 hours, with a moon named Xiangliu. Named for a Chinese water god, it swings from 34 to 101 AU on a 554-year orbit; see that long ellipse in the orbit view.
The orbit of Gonggong at this moment: https://nowsky.org/solar/orbit?fw=gonggong&sp=220 — replayed live, no login.
Orbit and size
| Diameter | ~1,230 km |
|---|---|
| Distance | 34~101 AU |
| Year | 554 yr |
| Note | very red surface; moon Xiangliu |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Frequently asked
- How big is Gonggong?
- ~1,230 km.
- How far is Gonggong from Earth?
- 34~101 AU.
- What is notable about Gonggong?
- very red surface; moon Xiangliu.
The water god who tilted the sky, and his nine-headed serpent
In Chinese myth Gonggong is the god who rules water. Defeated in battle by the fire god Zhurong, he rammed Mount Buzhou, the pillar holding up the sky, in fury, tilting the heavens to the north-west and sinking the land to the south-east — a story that explains why China's rivers flow east and the stars set in the west. When Gonggong won the 2019 naming vote over Holle and Vili, the body's red colour and its water ice were felt to suit the god.
The moon Xiangliu is named from the same myth: the nine-headed serpent that served Gonggong and fouled the waters wherever it went, until Yu the Great killed it. The moon was found in Hubble images in 2016, about 100 km across, circling Gonggong every 25 days. It allowed Gonggong's mass to be calculated, revealing a density 1.7 times that of water.
The dwarf planet in depth
Gonggong went by the provisional designation 2007 OR10 for years after its discovery, earning the nickname 'the largest unnamed object in the solar system' until a public vote in 2019 named it for the Chinese water god who unleashed floods. About 1,230 km wide, it is the fifth-largest body known beyond Neptune, and it travels a long ellipse from 34 to 101 AU every 554 years.
Its surface is among the reddest in the Kuiper belt, thanks to a thick layer of tholins — methane ice altered by sunlight and cosmic rays — with traces of water ice mixed in. Its unusually slow 22-hour rotation is probably the result of tidal interaction with Xiangliu, a moon Hubble found in 2016 and named for a nine-headed serpent. A 3:10 resonance with Neptune keeps its orbit stable over the ages.
Track Gonggong in the orbit view to see an orbit that stretches far past Pluto's, out to 100 AU. It is currently near aphelion at about 88 AU — the hardest time to observe it — and will not reach perihelion again until the year 2857.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.