With only 8 major planets, Pioneer 10 now becomes a problem

One of my UK friends, Barty, has an interesting and amusing take on the recent decision of the International Astronomical Union (IAU) to strip Pluto of its status as a fully fledged planet. According to the IAU, the solar system should be described as having eight major planetary bodies, with Pluto, Charon, Ceres and UB313 merely classed as 'dwarf planets'.

"The IAU have made a brave move by demoting Pluto. I'm sure they've realized that educators will be annoyed by the cost of updating all the textbooks and mnemonics, and I expect they're fully prepared for complaints from the Jedi community about a great disturbance in the Force, as though a million voices cried out, and were suddenly silenced. What I think they've failed to take into account is the mild niggling unease that will be felt by any of us pedants who know about the Pioneer 10 and Pioneer 11 spacecraft and the plaques they carry."

The plaques include a map of our solar system of nine planets. D'oh!

"Where was I? Oh yes, according to the plaque, the two Pioneers are each only about one and a half times the height of a naked human, and according to NASA they're not heading near anywhere inhabited. The craft, therefore, are unlikely to encounter anything except interstellar vacuum for billions and billions of years. NASA reckon that Pioneer 10 will still be in fairly good condition when the Earth and the Moon are destroyed by the Sun. It should even outlast the Sun itself. Even when you lot, me, the IAU, and everyone else is gone, Pioneer 10 will still be shiny and new. Assuming we don't escape extinction by leaving our star system, Pioneer 10 will be the last human-made thing to survive. In all likelihood, even when everything we were has gone, and even when everything we have ever built has been cooked to dust in the heat of a dead star for millions of years, Pioneer 10 will still be drifting silently. I find an odd comfort in the notion that the last thing that will remain of Humanity will be a slightly worn spacecraft, still carrying a plaque commemorating long-dead Pluto as a fully fledged planet."