What a Wonderful World

In the wake of this week’s reprehensible political violence, I needed a side trip off the planet. No, I haven’t gone to the pearly gates, but I recently became aware of Mexican theoretical physicist, Miguel Alcubierre Moya[1], who has solved a specific case for Einstein’s field equations in general relativity to develop a serious proposal for matter traveling Faster Than Light (FTL).

The “Alcubierre drive” proposal involves a “ship” that is capable of distorting the space and time field around it so that space-time in front of the ship is negative and space-time in back of the ship is positive. Hence the ship appears to be “pushed” through space-time from the rear and “pulled” from the front. The only thing we know of that distorts space-time is the intense gravitational field of a black hole. Some people claim that Alcubierre (who is 57) got his inspiration watching the “Warp speed” on Star Trek episodes as a child; although I have not confirmed it.

To an observer in our earth-bound, ordinary frame of reference, such a ship would seem to vanish from sight like Jesus or Elijah ascending to heaven in a cloud. (Or, more accurately, like Jodie Foster’s worm-hole travel in the movie “Contact” written by Carl Sagan.) To the passengers on board, they would experience no gravity (weightlessness) and no acceleration forces (like being in a jet at takeoff). They would float around like angels.

Navigation in such a ship would be tricky but not impossible. It is not clear how “fast” the ship would travel especially since what we call speed or velocity is distance divided by time and both of those quantities are distorted beyond imagination by such a ship. Inside the ship would be a zero-gravity bubble. The walls and outside the ship would be the most intense gravity possible. It would rip ordinary matter apart. It is possible that travel in an Alcubierre ship would be like getting on an elevator (without the tug of gravity). You step into the elevator on one floor and arrive a thousand-trillion miles away and thousands of years earlier when you get off.

It would take me a month of review just to understand the first sentence of the mathematics section describing the Alcubierre drive in Wikipedia.  Here [2]it is.

“Using the ADM formalism of general relativity, the spacetime is described by a foliation of space-like hypersurfaces of constant coordinate time t, with the metric taking the following general form:

            ds2 = – (α2 – βi βi) dt2 + 2 βi dxi dt  ˧    γij dxi dxj


  • α is the lapse function that gives the interval of proper time between nearby hypersurfaces,
  • βi is the shift vector that relates the spatial coordinate systems on different hypersurfaces,
  • γij is a positive-definite metric on each of the hypersurfaces.”

If you think understanding theology or other fields is difficult, count your blessings.


[1] https://en.wikipedia.org/wiki/Miguel_Alcubierre

[2] https://en.wikipedia.org/wiki/Alcubierre_drive#Mathematics

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