How far away from Earth is Europa?

Question posed by cuyla.

Europa orbits the planet Jupiter at an average distance of just over 670,000 kilometres. Compared to the 750,000,000 kilometre orbit of Jupiter around the Sun, this is pretty much nothing at all, so it makes sense to treat Europa as if it is the same distance away from us as Jupiter is. Another reason to do this is that due to Earth's rotation around the Sun, Jupiter's rotation around the Sun, and Europa's rotation around Jupiter, it's almost meaningless to put an actual value on how far away we are from Europa because it changes all the time.

However, in the post How far away from the Sun is Jupiter? I also talked a little bit about how far Jupiter is from the Earth and, although the distance changes (for the same reasons outlined above), put some numbers on the greatest and smallest possible distances between the two. The answer, to any sensible degree of accuracy, would be pretty much exactly the same for Europa. If you're desperate for some greater accuracy, then all you need to do is read the article linked above, then subtract Europa's apoapsis* from Jupiter's closest approach to the Earth, and add it on to the furthest apart that Earth and Jupiter find themselves, but it won't make a lot of difference.

If you're not that bothered about accuracy, we could say that as Jupiter (and therefore Europa) orbit the Sun at about 5 AU and Earth orbits the Sun at about 1 AU, then over the years we find ourselves wobbling between being about 4 AU and 6 AU away from Europa!





* 676 938 km

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