john/nyc wrote:..........Does inertia bring light (its photons) to expend itself? That is, is there a distance which is so great that light will be unable to traverse it? Does light die?
john; inertia is the tendency to remain in the state of motion that exists; accelleration, positive, or negative, requires the expenditure of energy, thus it must be external forces that slow things down.
since light travels @ C (requiring light to be an energy form, not a mass, even though photons can have 'mass' - a little unexplained conundrum, that keeps the theoreticians happy) it has the maximum amount of inertia that is theoretically possible. Unimpeded, it would travel forever; but, of course it does, over huge amounts of time/distance meet resistance from various objects, not large enough to block the light, but able to impact it, thus slowing it down. In theory, if light is slowed down, it ceases to be light, but, perhaps, morphs into mass which renders it no longer visible(?).
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[caution; total conjecture below - 'real' physicists should wear protective gear!]
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On the subject of accelerating to the speed of light, i see the universe as two opposing forces; the one centripetal, or 'binding' force being gravity, and the other centrifugal, or 'destructive' force being an unknown entity - possibly the source of the 'big bang' - which uncontended would create total chaos (should we call it 'god'?)
'inertia' being the standard (politely conservative) state of motion, for all matter in the universe; this is the result of the opposition of these two forces; movement being the imbalance of such.
So acceleration requires a modification in the balance between these two, to affect a change in the inertial state of the object.
Thus we have a new definition of "energy"; the variance in balance between the warring kinetic forces in the universe.
[i now don my 'abuse' armour, and wait.]