Bolted to the side of Pioneer 10 is a gold-anodised aluminium plaque, about 152 by 229 millimetres, engraved with the figures of a man and a woman and a set of symbols meant to mark where and when the spacecraft came from. The craft that carries it has been silent for more than two decades. [...] The post Bolted to Pioneer 10 is a plaque showing two humans and a cosmic map back to Earth, while the spacecraft itself is now a silent ghost ship drifting toward Aldebaran, a star it will not pass for