Europa
What is Europa?
Moons· Diameter 3,122 km. An ice-shelled moon hiding more water than all Earth's oceans. Europa Clipper arrives in 2030 to see whether that dark sea could host life.
📍 Visible from where you are right now — computed in your browser
bearing · altitude · rise time · best time tonight
The orbit of Europa at this moment: https://nowsky.org/solar/orbit?fw=moon:jupiter:europa&sp=0.015 — replayed live, no login.
Orbit and size
| Diameter | 3,122 km |
|---|---|
| Parent | Jupiter |
| Note | buried ocean, 2× Earth's seas |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
Parent planet and sibling moons
Related events
Frequently asked
- How big is Europa?
- 3,122 km.
- What is notable about Europa?
- buried ocean, 2× Earth's seas.
- Which planet does Europa orbit?
- Jupiter.
Why 49 flybys instead of an orbit
After reaching Jupiter in 2030, Europa Clipper will not enter orbit around Europa but loop widely around Jupiter and sweep past the moon 49 times. The reason is radiation. Europa sits inside the belts of high-energy particles trapped by Jupiter's magnetic field, and a spacecraft parked in its orbit would lose its electronics within months. Spending only hours inside the belts on each pass and retreating between them is what stretches the mission to four years.
The passes drop as low as 25 km and each follows a different track, so together they tile the whole surface. Ice-penetrating radar measures the thickness of the shell, and a mass spectrometer will taste molecules in any plumes rising from the surface. Clipper's solar arrays span 30 m, the largest on any NASA planetary spacecraft, and its electronics sit inside a thick metal vault to survive the radiation.
The moon in depth
Beneath Europa's ice shell lies more liquid water than in all of Earth's oceans — a global sea 60–150 km deep, kept warm by the tidal kneading of Jupiter's gravity. The red fractured streaks across its surface read as places where that ocean has forced its way up.
Liquid water, an energy source, and chemistry: with all three likely present, Europa is the solar system's best-rated place to look for life. Europa Clipper (arriving 2030) will measure the ice thickness and ocean chemistry across 49 close flybys.
Zoom to Jupiter in the orbit view to watch Europa lap the planet every 3.55 days — its 1:2:4 resonance with Io and Ganymede is the secret engine of the tidal heat.
Europa's ocean stays liquid by the same tug-of-war that fires Io's volcanoes — Jupiter's gravity and the neighboring moons' resonance knead the ice shell warm. Hubble has repeatedly glimpsed candidate water-vapor plumes venting from the surface; if real, we can taste the ocean without landing. Clipper's 49 flybys will settle the plume hunt for good.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.