All the Bridges Rusting Larry Niven Produced by calibre 0.6.40 All the Bridges Rusting Take a point in space. Take a specific point near the star system Alpha Centaurus on the line linking the center ofmass of that system with Sol. Follow it as it moves toward Sol system at lightspeed. We presumea particle in this point. Men who deal in the physics of teleportation would speak of it as a quottransition particle.quot Butthink of it as a kind of super-neutrino. Clearly it must have a rest mass of zero like aneutrino. Like a neutrino it must be fearfully difficult to find or stop. Despite severaldecades in which teleportation has been in common use nobody has ever directly demonstratedthe existence of a quottransition particle.quot It must be taken on faith. Its internal structure would be fearfully complex in terms of energy states. Its relativisticmass would be twelve thousand two hundred tons. One more property can be postulated. Its location in space is uncertain: a probability densitythousands of miles across as it passes Proxima Centauri and spreading. The mass of the tinyred dwarf does not bend its path significantly. As it approaches the solar system the particlemay be found anywhere within a vaguely bounded wave front several hundred thousand milesacross. This vagueness of position is part of what makes teleportation work. Ones aim need notbe so accurate. Near Pluto the particle changes state. Its relativistic mass converts to rest mass within the receiver cage of a drop ship. Itsstructure is still fearfully complex for an elementary particle: a twelve-thousand-two-hundred-ton spacecraft loaded with instruments its hull windowless and very smoothly contoured. Itspresence here is the only evidence that a transition particle ever existed. Within the controlcabin the pilots finger is still on the TRANSMIT button. Karin Sagan was short and stocky. Her hands were large her feet were small and prone to foottrouble. Her face was square and cheerful her eyes were bright and direct and her voice wasdeep for a womans. She bad been thirty-six years old when Phoenix left the transmitter atPluto. She was three months older now though nine years had passed on Earth. She had seen a trace of the elapsed years as Phoenix left the Pluto drop ship