Alcubierre metric. (CC-BY-SA) Allen McC.
Slashdot brings up another resurgence of Warp Drive in the media. While it'd be amazing, it's still at the theoretically interesting stage. Though the theory is good, it requires a lot of energy. While before it required energies similar to that of the universe, now it seems like it will need only about 1045 J. This is in the ballpark of about 5.9 jovian masses. So, better, but still pretty impractical.
The figure at the right pretty cleanly describes the effect. In essense, spacetime is compressed and expanded around the ship so it can "surf" on a wave of expanding spacetime, which itself "moves" faster than c=299792458 m·s-1, but the spaceship itself remains stationary and thus violates no physics. It is, in a fairly literal sense, a warp drive. It is perfectly valid for space to have superluminal expansion rates; distant objects in our Hubble Volume recede from us at apparently faster than light, and the hyperinflationary epoch was defined by an incredible, superluminal spacetime expansion.
The whole thing is based on the Alcubierre metric, described by
Alcubierre metric. Variable definitions as used by Alcubierre available at Wikipedia
In a very technical sense, this is not a solution to the Einstein Field Equations, but rather has ADM forms that can be adapted to various observers that are actually not physically distinguished from each other. However, as a Hamiltonian formulation, the solution is not exactly one to the EFEs, but is much easier to work with and is often used in practical and theoretical studies.
This was probably one of my "denser" posts, so for those of you that understood it, I give you an icon to use:
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