Thomas was not letting Fey leave. Obviously, she was very close to Christine to know about such an amazing capability. After all, if they had known how to manipulate space-time, nothing could have kept him and his friends in the Tibetan Plateau. Fey smiled at Thomas and pointed her head up, hinting at an exit on the ceiling for emergency. One step closer would be the end of discussion between them. Seeing no way to block Fey, Thomas kept a distance. Both Emma and Nathan were watching.
“Wait!” Thomas was rather prudent, asking about Nathan’s hypothesis instead, “If energy can be infinite outside of space-time, why consider it as one same entity called space-time-energy?”
“Well,” Fey replied, “it depends on whether you are talking about space-time-energy as a velocity vector or a medium. Since you are asking about energy being outside of space-time, you obviously are referring to space-time as a medium, in which case you obviously have to prove it first. Plus, that energy can leak into space-time means that some sort of time exists also outside of space-time for energy to flow from outside in. So, maybe space is single and not so married to time and energy. But, wait! For any flow to occur, it takes also space. So, there is also some sort of space outside of space-time. What then makes the difference? Ah, inner space-time responds to gravity, hence creating a barrier to entry for outer energy! From a biological point of view, of which I am an expert, inner space-time is denatured, or cooked, in gravity. What produces gravitational mass? Invariant mass! What produces invariant mass? Charge? Inertia? Who knows?”
The kids were rather quiet again. Amused, Fey continued her ramblings, this time a little more serious.
“If inner space-time is a medium, there is a possibility that when energy enters it, space-time-energy is formed such that all five dimensions reflect the absolute speed of an object as three important attributes of the same entity that define a local frame of reference, because all three physical changes occur instantaneously while two of them actually constitute the definition of speed, all by the magical power of logic. Relativistic kinetic energy is therefore acquired from outer space-time when an object within inner space-time speeds up and released back to outer space-time when it slows down. However, Nathan could be right about energy leaking into space-time upon a transfer of momentum only, in which case energy flow would be asymmetric. He has to prove it. The best way to reason about space-time is to see the velocity of an object as its altitude above space-time, in which case the kinetic potential energy of the object is conserved. This explains why space and time are interdependent while energy depends on both. Now, both space and time depend on gravity in general relativity. That’s the interesting part, because everything depends on it.”
At this point, Nathan interrupted, “All these are old school in the human world. They already knew this when Einstein published his general relativity back in the 20th century.”
“It’s true,” Fey replied, “but they did not talk about the possibility of photons being quasi-particles like phonons, which probably cannot escape space-time or even exist outside of space-time. Without the speed of light as a speed limit and an infinite amount of energy at our disposal, a lot of things can happen outside of space-time. Now, it could be that relativistic kinetic energy is generated out of nothing within space-time when an object accelerates and that there is nothing outside of space-time. However, there is still much engineering we can do based on this fact alone, because we still have access to potentially infinite energy, which is sufficient for most purposes. Actual infinity is not that useful unless we have its mathematics first.”
Since she was talking about mathematics, Fey turned to Emma, “I still like the hypothesis that gravitational mass is invariant mass, because it is definitely not inertial mass in the context of a black hole. Now, if gravitational mass is not invariant, the function that describes it is anyone’s guess, which, however, must still be negligible within the relativistic framework. If there is no physical significance to be found in the new physical framework, we are not supposed to waste our time on it. This is why I prefer to stay with Einstein’s general relativity by default. There is no reason to make an effort for nothing.”
Seeing no reaction from Thomas, Fey asked him, “May I go now or do you prefer that I talk about gravity-space-time-energy as one same entity for yet another theory? If I don’t have to be sure, I can keep on talking like this forever, but if I have to be sure, then you better let me leave.”