The Alcubierre-White Warp-drive

I thought this tweet from Elon Musk very interesting:

If we create a city on Mars, Earth-Mars travel will be a powerful forcing function for inventing something like warp drive.

Is the warp drive (faster-than-light space travel) anything more than an intriguing scientific concept?  We all know that we cannot go faster than the speed of light, right?  So it's impossible, yes?

Well, maybe not.  Back in 1994, Miguel Alcubierre, a fan of Star Trek and a physicist/mathematician, demonstrated that faster-than-light travel did not violate Einstein's theory of general relativity. Essentially, Alcubierre's warp drive worked by squeezing space up in front of the spaceship and dilating it behind, so the spaceship itself was not technically travelling faster than light.  In fact, within a bubble of space-time surrounding the ship, it was stationary—it was the bubble itself which was travelling faster than space-time.   However, it did require exotic materials—particles with negative mass.  Which no one has yet seen or created, though there's no reason why they shouldn't theoretically exist.  Plus, the energy requirement would equal all the energy available in the universe.  So warp-drives went from theoretically impossible to theoretically possible but impractical.

In 2003, Harold White of NASA's Eagleworks laboratories sketched out a way to make the Alcubierre drive feasible, and he published his findings in a paper in 2011.  White's concept of the FTL drive makes use of positive, normal matter.  His model achieves this by means of a high-frequency oscillating torus, which "softens" space-time.  This creates a spherical warp-field "bubble" of space-time within which the spacecraft is held, which is separated from external space-time.  This means that the spacecraft never really exceeds light speed within that bubble.  This technique dramatically reduces the energy required.

Most people now call this the Alcubierre-White warp-drive.

Technology responds to need.  Just as the industrial revolution began with leapfrogging developments in spinning and weaving machines, an increase in the effectiveness of one driving improvements in the other, so rising demand for speedier transits to Mars will push technicians and engineers to do better.  We don't even need light speed.  It takes 3 minutes at 'orbital sync' for light to travel between Earth and Mars.  At our fastest trajectories, it will take Starship 3 months to do that.  In other words, right now we can travel at 0.002% of the speed of light.  Even 0.01% of the speed of light would cut the journey to 18 days.  Musk is right.  When we have hundreds of thousands of people on Mars (and tens of thousands in the asteroid belt), some of the brightest minds in the world will be bending their efforts to bending space.

I won't be alive to see it, but you, dear reader, might.

This is an entertaining video which explains the basics of the Alcubierre-White warp-drive.