Nano Starships

Michio Kaku's new book, Physics of The Impossible, is filled with interesting ideas and informed speculation. One chapter covers starships, and whether interstellar travel is possible given the laws of physics as we understand them. Kaku thinks manned interstellar flight is likely possible, though we may be centuries away from being able to do that.

Another possibility he considers is also interesting, however. With advances in nanotechnology, sending tiny unmanned probes to the stars would be possible. Such probes could be smaller than grains of sand. We could launch billions of them to a star at speeds approaching the speed of light using one of a few possible propulsion schemes; if even a tiny fraction of the probes survived the mission to send back data, the project would be a success. More advanced self-replicating machines could also use the raw material they found in a solar system to reproduce and head for the next star, bouncing from one system to another, every few years or decades contacting Earth with new discoveries. Kaku thinks the first unmanned interstellar flight, using nanoprobes or some other approach, could conceivably leave Earth yet this century.

Of course, if we find a close cousin of Earth orbiting one of the nearby stars before then, sending a mission there could move up the schedule.