Radiolab did a great summary of this just a couple of months ago: http://www.radiolab.org/story/sun-dont-shine/ http://www.radiolab.org/story/sun-dont-shine/ Yo

Radiolab did a great summary of this just a couple of months ago: http://www.radiolab.org/story/sun-dont-shine/ http://www.radiolab.org/story/sun-dont-shine/ You can skip the parts about the time capsule if you want. tl;dr: it's not clear what defines the edge of the solar system, there's interesting reasons to want to know where it is, and voyager taught us a lot about it.