Where is Europa?

"Where is the moon Europa?" - Question posed by Mikayla.

By NASA/JPL, via Wikimedia Commons
Europa, as snapped in 1979 by Voyager 1
I've answered the question How Far Away From Earth is Europa already, but I can agree that this is a slightly different question, so I'll try to give you a slightly different answer!

We, on Earth, orbit the Sun at a distance of roughly 150 million kilometres, or 1AU. About five times further away from the Sun, at about 800 million kilometres (or 5AU), orbits our solar system's biggest planet, Jupiter.

Jupiter has a system of moons that orbit it in the same way that the planets orbit the Sun. So far, Jupiter has 64 natural satellites* that we have named, and probably many more to be be discovered. Of these, four stand out from the crowd: the Galilean moons, collectively named after their discoverer and individually named Io, Europa, Ganymede and Callisto.

Europa is the second closest of the Galilean moons to Jupiter (after Io), and travels in a 421,700 km orbit that is very nearly circular. Inside the orbit of Io are four smaller moons named Metis, Adrastea, Amalthea and Thebe. This makes Europa the 6th moon out from Jupiter.

If you want to send a letter to someone on Europa**, you might use the following address:

     6th rock from Jupiter,
     5th planet from the Sun,
     The Solar System,
     The Milky Way (Orion- Cygnus Arm)

Sorry, I don't know the postcode.

* 'Natural satellites' are what we more commonly refer to as 'moons'.
** And you might well do- it's one of the most interesting candidates in our solar system with regards to the possibility of extra-terrestrial life!


  1. Do you think there is enough evidence to support the theory that Europa may have liquid water beneath its surface?

  2. That's a good question... I think I'll do a post on it!


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