Dance of the Photons

From Einstein to Quantum Teleportation

Anton Zeilinger

Farrar, Straus and Giroux

DANCE OF THE PHOTONS
SPACE TRAVEL
When we hear of teleportation, we often think it would be an ideal means of traveling. We would simply disappear from wherever we happened to be and reappear immediately at our destination. The tantalizing part is that this would be the fastest possible way of traveling. Yet, a warning might be in order here: teleportation as a means of travel is still science fiction rather than science.
Thus far, people have only been able to travel to the Moon, which on a cosmic scale is extremely close, the equivalent of our backyard. Within our solar system, the closest planets, Venus and Mars, are already roughly a thousand times more distant than the Moon, to say nothing of the planets farther out in the solar system.
It is interesting to consider how long it would take to go to other stars. As we all remember from the Apollo program, which put the first men on the Moon, it takes about four days to go from Earth to the Moon. Traveling by spaceship from Earth to the planet Mars would take on the order of 260 days, one way. It is evident that our space travelers would get quite bored during that time, so they might make good use of their time by performing experiments involving quantum teleportation.
In order to get even farther out, we might use the accelerating force of other planets or even of Earth itself, as has been done with some of the unmanned spacecraft exploring outer planets. The idea is simply to have the spaceship pass close by a planet so that, by means of a sort of slingshot action, it can be accelerated into a new orbit that carries it much farther outward. For example, using these methods, the spacecraft Pioneer 10 took about eleven years to travel past the outermost planets of the solar system on its probably unending journey into thespace between the stars. We can thus estimate that it will, for example, take Pioneer 10 about 100,000 years to get to Proxima Centauri, the closest star except for the Sun, at its current speed.
Perhaps, therefore, it would be good to have some other way to get around, to cover large distances. What we want is to travel anywhere instantly, without any limitation on how far we can go. Is that possible, at least in principle? This is why science-fiction writers invented teleportation. Magically, you disappear from one place, and, magically, you reappear at another place, just an instant later.
Copyright © 2010 by Anton Zeilinger