So now, then . . .
If we are to take seriously the notion that there is no simultaneity in the cosmos, which surely we must do. And if therefore there is no precise position to anything short of its actual measurement; that it is the impingement of the thing which we already know must exist since its context makes that essential, but that we can be no more precise about it's actual position than indicated by its de Broglie wavelength, however diminishingly small for the largish among us. What I propose, quite simply actually, is that there is something analogous to this wavelength which defines the indeterminacy of things in relative motion, such that it is not simply that they age rather more slowly than do we at rest, but that they become, as it were, indistinct and perhaps apart. It is the caring which blurs. The emotional connection which erodes and eventually disappears entirely, if for no better reason that that it would take nearly all of our physical energy even to create a very significant distance in the first place.
We would have to be really really angry, say, or be driven by something very much larger than love to accomplish any connection at all across paradoxial divides such as that illuminated by separating twins. It is not their relative ages which paradoxically cross, but their inertial wavelengths which relatively blur, and fail eventually, to intersect at all, anymore and forever, insofar as any of those terms are sensible!
If I gave a fig for the trueing capabilities of the formal and logical languages of mathematics (which, of course, I actually do - it's just that I'm too damn lazy and aged out to do anything about it) I would further propose a direction for investigation of this very thing. I think the equation might involve a ratio between emotional and physical connection; a kind of conceptual/perceptual relation which might predict the horizon for recognition of quirky alien intelligence, say, rather than the existence of a new quarky particle.
Of this I am relatively certain: There is no experimental proof even conceptually possible of the continued existence of perhaps once cared for percepts beyond the threshold of caring, since it would be the caring which would be proven before the only apparently sought for answer could ever be grasped. I think that's a perfect tautology, but oh well! You were expecting maybe a solution? A formula? E=MC² defines a threshold, is all. A limit. Beyond that pale, there is no caring, since there is no conceiving.
But here, true heart, on this side of the perceivable cosmos, are wonders as yet unbeheld, as we grasp too tightly the instrumentation of our undoing, the digitized simulacrum of actual stimulus. We can only measure further our own smallness in that particular direction. Outward recedes. Heart withers. Response is to our individual selves alone. All One.