10 Need-To-Know Things About Europa:
- If the sun were as tall as a typical front door, Earth would be the size of a nickel and Europa would be the size of the dome on the back of the nickel.
- Europa is a moon that orbits the planet Jupiter. Jupiter is the fifth planet from the sun at a distance of about 778 million km (484 million miles) or 5.2 AU.
- One day on Europa (the time it takes for Europa to rotate or spin once) takes about 3.5 Earth days. The length of Europa's day is the same as the amount of time it takes Europa to orbit Jupiter. Jupiter makes a complete orbit around the sun (one Jupiter year) in about 12 Earth years (4,333 Earth days).
- Like many other moons (including Earth's moon), Europa is locked by gravity to its planet so that the same side always faces toward Jupiter.
- Europa's surface is mostly solid water ice. It is extremely smooth and crisscrossed by fractures.
- Europa has an extremely thin oxygen atmosphere -- far too thin to breathe.
- Europa does not have rings.
- Europa and Jupiter have been visited by eight spacecraft, which have performed flybys. Galileo is the only mission to make repeated visits to Europa.
- With abundant liquid water, and energy and chemistry provided by tidal heating, Europa could be the best place in the solar system to look for present day life beyond Earth.
- If Europa's ocean is proven to exist, it would possess more than twice as much water as Earth.