Enceladus
What is Enceladus?
Moons· Diameter 504 km. A small moon venting its buried ocean into space through south-pole geysers — organic molecules ride those plumes, making it a top astrobiology target.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
The orbit of Enceladus at this moment: https://nowsky.org/solar/orbit?fw=moon:saturn:enceladus&sp=0.008 — replayed live, no login.
Orbit and size
| Diameter | 504 km |
|---|---|
| Parent | Saturn |
| Note | south-polar geysers feed the E ring |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Parent planet and sibling moons
Frequently asked
- How big is Enceladus?
- 504 km.
- What is notable about Enceladus?
- south-polar geysers feed the E ring.
- Which planet does Enceladus orbit?
- Saturn.
The whitest surface in the solar system, and therefore one of the coldest
Enceladus reflects 99 percent of the sunlight that falls on it — whiter than fresh snow, the highest albedo of any body in the solar system. Ice grains thrown up by the south-polar geysers fall back as snow and keep coating the surface anew; the nearly craterless southern hemisphere is where, geologically speaking, that snow fell yesterday.
Reflecting nearly all its sunlight, the surface stays below −200 °C even at noon. That contrast between a frozen skin and the liquid ocean beneath is the paradox of Enceladus: the coldest exterior in the solar system over an interior warm enough for hydrothermal vents. The temperatures Cassini measured above the south-polar fractures ran nearly 100 degrees above their surroundings — places where the heat from below leaks straight out.
The moon in depth
Enceladus is only 504 km across, yet the geysers jetting ocean water from its south-polar 'tiger stripes' made it a top target in the search for life. The frozen spray builds Saturn's E ring.
Cassini flew through the plumes repeatedly (2008–2015), finding salt, silica grains, molecular hydrogen and even phosphorus — strong evidence of hydrothermal chemistry like Earth's deep-sea vents. It is the only alien ocean where all six bioessential elements have been confirmed.
Future missions are being designed to fly the plumes again hunting biomolecules directly. Zoom to Saturn in the Orbit view and find Enceladus inside the E ring.
Enceladus's plume has already yielded the ingredients list: flying straight through it, Cassini tasted salt, organics, hydrogen, and phosphorus compounds. The hydrogen signals hydrothermal vents on the seafloor — the same chemical energy source that feeds ecosystems at Earth's deep-sea vents. Just flying through the plume again would count as a life-detection mission; no landing required.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.