Dear Dr. Lobo,

Regarding the "tantalizing hints that the NEC *might* possibly be violated in a classical regime" (gr-qc/0406083 v1, p. 1), see the reference frame for dark energy,

http://God-does-not-play-dice.net/Hongsheng.html

http://God-does-not-play-dice.net/Azbel.html#self

BTW have you noticed that your thoughts propagate in your mind just like some "reaction-less drive"? More on the human brain at

http://God-does-not-play-dice.net/Beauregard.html#note

You and Matt wrote: "In particular we wish to sound a strong cautionary note against over-enthusiastic mis-interpretation of the technological situation."

Sure, but let's not forget that some some reaction-less drives, resembling "light balls", were recorded by the Mexican Air Force on
March 5, 2004,

http://www.cnn.com/2004/WORLD/americas/05/11/mexico.ufos.ap/

http://God-does-not-play-dice.net/Mexico_UFO.html

Maybe some guys have managed to eliminate the inertia of their "light balls" and can move them just like we move our thoughts.

If you think this is impossible, see how terribly little we know about gravity, in ref. [15] in your gr-qc/0406083 [C. Barcelo and M. Visser, "Twilight for the energy conditions?," Int. J. Mod. Phys. D 11, 1553 (2002); gr-qc/0205066].

I just want to issue a gentle cautionary note against possible over-enthusiastic mis-interpretations of the nature of gravity.

Regards,

Dimi Chakalov
35 Sutherland St
London SW1V 4JU
http://God-does-not-play-dice.net
 
 

Regarding my gentle cautionary note: Francisco Lobo and Matt Visser used the so-called linearized gravity (gr-qc/0406083, Appendix C), which is convenient but highly deceptive approximation; see their linearized Einstein equation, Eq. C8.

"Complex problems have simple, easy-to-understand wrong answers", says Murphy.

For details, see Angelo Loinger and T. Levi-Civita, as well as the last paragraph of John Bell's "An Invitation to Smooth Infinitesimal Analysis", where he commented on Misner, Thorne & Wheeler's Gravitation. We must never use such textbooks that have missed the essential problems of General Relativity, because our students will never comprehend the very foundations of general relativity.

Linearized gravity: that's an oxymoron, Matt! How many kids have been brainwashed so far by you? Hundreds? Give me a rough estimate, please.
 

D. Chakalov
June 22, 2004