07-07-2015, 03:11 PM

If you could pack bits at 1 bit per neutron or proton, a kilogram contains 6.022e26 bits. By Landauer's principle, clearing 6.022e26 bits costs at least 6.022e26 * 1.38e-23 * T * ln(2) = 28801 joules at 5 degrees Kelvin. That many joules could accelerate that 1kg to 28801 meters per second. The escape velocity from the sun is 617000 m/s, which is about 22x greater than that, so this design is a complete waste if transferring momentum to incoming to outgoing rocks consumes over 1/22 of the momentum. If it takes the weight of 10 or 100 neutrons to represent a bit, that 22x becomes 220x or 2200x.

If that 617000m/s were a slower speed (like 100m/s), I can handwave how to do that. Have a big incoming rock, a stationary outgoing rock, and a very long rope hooked to the outgoing rock. Hook it onto the incoming rock as it comes by so the rope is perpendicular to the incoming rock's velocity. The whole system will go taut and rotate, bringing the incoming rock momentarily to stationary while the outgoing rock is going at the same speed the incoming rock had been coming, in the same direction. Release the rope from the outgoing rock at that instant. Tah-dah, except for the momentum stuck in the rope, which can easily be made less than 1/220 of incoming rock's original momentum. But with an escape velocity of 617000m/s I don't think a rope would work. Transferring momentum that efficiently at high speeds is something I don't know how to do. It sounds like a difficult but not necessarily impossible problem. The smaller the system, the smaller the escape velocity, and the easier this piece of the design is to solve.

If that 617000m/s were a slower speed (like 100m/s), I can handwave how to do that. Have a big incoming rock, a stationary outgoing rock, and a very long rope hooked to the outgoing rock. Hook it onto the incoming rock as it comes by so the rope is perpendicular to the incoming rock's velocity. The whole system will go taut and rotate, bringing the incoming rock momentarily to stationary while the outgoing rock is going at the same speed the incoming rock had been coming, in the same direction. Release the rope from the outgoing rock at that instant. Tah-dah, except for the momentum stuck in the rope, which can easily be made less than 1/220 of incoming rock's original momentum. But with an escape velocity of 617000m/s I don't think a rope would work. Transferring momentum that efficiently at high speeds is something I don't know how to do. It sounds like a difficult but not necessarily impossible problem. The smaller the system, the smaller the escape velocity, and the easier this piece of the design is to solve.