The whole concept of the "termination shock" has always been interesting to me. It's a boundary where the charged particles and radiation from the solar wind meet the incoming "wind" from the rest of the galaxy, nearby stars, etc. While theories abound, nobody really knows for sure what goes on in true "deep space" (the area between the stars) so this is pretty exciting. It's just a shame that we didn't have the technology in the seventies to pack a bunch of sensors on Voyager to send back information on exactly what it finds out there.
(SPACE.com) -- Voyager II could pass beyond the outermost layer of our solar system, called the "termination shock," sometime within the next year, NASA scientists announced at a media teleconference Tuesday.
The milestone, which comes about a year after Voyager 1's crossing, comes earlier than expected and suggests to scientists that the edge of the shock is about one billion miles closer to the sun in the southern region of the solar system than in the north.
Scientists determined that Voyager I was approaching the termination shock when it began detecting charged particles that were being pushed back toward the sun by charged particles coming from outside our solar system. This occurred when Voyager 1 was about 85 AU from the sun.
Of course, we left a map showing how to get to our planet on that craft, so if any wandering extraterrestrials happen to pick it up out in the deep black... well, set an extra place for dinner. Who knows? We may have company.