The Pioneer Plaque

With the hopes of being intercepted by alien forms, NASA sent this plaque on Pioneer 10 in 1972 (and then on Pioneer 11 the next year). It shows, among other things, the relative position of our sun with respect to 14 pulsars, the figures of a man and a woman, and our own solar system. I will not write about the cleverness of the encoding, that should be deciphered by an extraterrestrial being, but about our own fallibility. The solar system depicted, inevitably, Pluto, which, together with Ceres and Eris, was degraded to a dwarf planet. So I imagine two scenarios. One, an alien life form finds the plaque and then us, but then dismiss us as a possibility after finding eight big planets and three smaller ones, instead of nine. Or two, we send another plaque, with our updated knowledge. And, in the event we should discover new bodies in the solar system, we would keep on sending plaques until we have filled the galaxy with our own gold coated spam mail. Or, we leave it to the software companies and the new plaques will become the service packs of interstellar travel.

The Pioneer Plaque on Wikipedia