Voyager Probes Nearing Termination Shock
Mr. Eradicator writes "The Voyager probes are continuing their journey away from the Solar System at a pace of 10 AU per year. They won't reach the heliopause until 2017, but they could arrive at a preliminary boundary called the termination shock as early as 2005. The termination shock, nearly 4 billion miles inside the heliopause, is where the solar wind first starts to slow down and reverse due to its first encounters with pressure from interstellar space."
If all this should have a reason, we would be the last to know.