Alderson drive
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The Alderson drive, named after Jet Propulsion Laboratory scientist Dan Alderson, is a fictional device that enables instantaneous interstellar transportation. It is featured in the CoDominium series of science-fiction novels by Jerry Pournelle, including the Mote series by Larry Niven and Jerry Pournelle. Dan Alderson helped Pournelle work out the notional science behind the drive, and how it should work to be a useful plot device.
[edit] Overview
The Alderson drive avoids the problem of travel faster-than-light by using a form of wormhole, whose entry and exit 'Alderson points' are at the ends of an 'Alderson tramline'. Alderson points are hard to find. They lie at points of equipotential thermonuclear flux, located near stars. Not all pairs of stars have Alderson tramlines between them, and even if a pair of stars has an Alderson tramline, it may be too weak for a spaceship to pass through. This means that travel from one star system to another often requires several steps, with travel through normal space between them. Alderson tramlines, when they form, form instantaneously, and travel between them appears to take no time at all. However, travel through an Alderson tramline causes disorientation in sentient brains and wreaks havoc on computers.
At the beginning of The Mote in God's Eye, by Larry Niven and Jerry Pournelle, only one tramline leads to Mote system. Its inner end is well above the plane of the local ecliptic and its outer end appears inside the photosphere of a red giant star. The Mote civilisations has long been able to construct an Alderson-type drive but, because they had no Langston Field technology, their many attempts to use an Alderson drive always failed. Then the battlecruiser INSS MacArthur arrived in their system, leading to the events in the novel and its sequel.
[edit] The science
In physics, four forces are known: gravity, electromagnetism, nuclear weak, and nuclear strong. The fictional science behind the Alderson drive assumes a fifth force, produced by thermonuclear reactions. The force has little effect in our universe and is barely detectable.
But in the Niven/Pournelle stories there is a parallel universe, the continuum universe, in which there are no known quantum effects or relativistic effects. In that universe, a spaceship can get from one place to another at any desired speed, powered by the thermonuclear force.
Travel from our universe into the continuum universe uses the fact that for every particle here, a correspondence particle can be created there. Given machinery that can hold all of your particles together, you can switch your spaceship to a corresponding spaceship in the continuum universe, travel instantaneously, and then switch back. The catch is that you can only do this at Alderson points, which have the same thermodynamic potential. To reach a given planet you must travel across its stellar system, and you must enter that system at one of the Alderson points. Thus the problem of travel between star systems is reduced to the problem of travel within star systems.
