The space time interval math only concerns itself with distance time and the speed of light. Why then, isn't there some local aberration of the fabric of space when two light beams ( lasers?) approach each other or even collide?
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1Can you explain what you mean by "aberration of the fabric of space"? – probably_someone Jan 27 '18 at 03:55
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As in "time like" as I believe the example above would be? – Jimm Jan 27 '18 at 04:01
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What does a time-like separation have to do with an aberration in the fabric of space? – probably_someone Jan 27 '18 at 04:03
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I don't know , but I thought it should affect clocks in the vicinity? – Jimm Jan 27 '18 at 04:05
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2Not as far as I know. Otherwise we'd be in trouble, as there's an awful lot of light going back and forth between objects. – probably_someone Jan 27 '18 at 04:05
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As the answer below suggests, the interference of high energy density radiation, be it light or otherwise, could indeed have an effect on space-time. – Jimm Jan 28 '18 at 15:49
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Firstly, it is not correct to think that there is a special exclusive relationship between relativity and light. Early thinkers, such as Einstein and Lorentz, stumbled onto special relativity owing to the unforeseen reference frame transformation law that light was observed to follow. But nowadays, we know that relativity can be thought of as separate from and more fundamental than light and arising from basic, light-independent symmetries of our universe as I, for example, discuss further in my answers here and here. In this (slightly) more modern view light is simply one of a number of things that are witnessed to propagate at speed $c$ (the other spectacularly-recently-experimentally proven one is gravitational waves; see Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A)). They do this because they are mediated by massless particles, not because there is anything special about light.
Secondly, in general relativity there is indeed an effect of light on spacetime, but this is only by dint of light's contributing to the stress energy tensor, thus acting on the geometry of spacetime through the Einstein field equations. But this is true of anything that changes the stress energy tensor. Light, intergalactic plasmas, stones in space being a few examples: there's nothing special about light here.
Indeed, there is a name for a theoretical phenomenon whereby so much light is concentrated into a small region of space that an event horizon forms. This is called a Kugelblitz. It's fairly easy to see how such a thing is a classical possibility (i.e. if you know general relativity alone) but, as we are talking about a stupendous energy concentration, I do no know how quantum effects disturb the idea.
Selene Routley
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