Jupiter, not so up close and not so personal

So you've probably heard that tonight, Jupiter is as close to Earth as it'll get in many years. While this is true, and pretty cool -- and I certainly don't want to damp enthusiasm for anyone wanting to go outside and see it! -- I want to make sure you understand what this means. First of all, this whole thing is happening because Jupiter is at opposition: that is, it's directly opposite the Sun in the sky. A better way to think of this is that the Earth is passing very nearly directly between the Sun and Jupiter, so from the Earth we see them on opposite sides of the sky. At this point, the Earth is as close to Jupiter as it can get for that particular orbit. Both Earth's and Jupiter's orbits are slightly elliptical, so sometimes Jupiter gets a bit closer to us at opposition than other ...