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Now, with special relativity applied to the scenario of me getting closer and closer to light speed, my mass would increase with respect to the observer, and also my length would contract in the direction of motion, again with respect to the observer. Now, if this is allowed to continue, there certainly would come a point where my mass would be observed to be very very high, and my length contracted to below my Schwarzschild Radius, now what would happen in this scenario? Would the observer observe a black hole while observing me? if not, what would the observer actually see?(If the observer sees me as a black hole, shouldn't that technically not happen since nothing is different to me from my own point of view!? )

Would I turn into a black hole? and if not, what would the observer see if I do not turn into a black hole? Would the observer notice any gravitational effects from me?

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  • $\begingroup$ I've deleted an extended comment discussion. That sort of thing should be held in Physics Chat. $\endgroup$
    – David Z
    Dec 21, 2014 at 16:14
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    $\begingroup$ @DavidZ: Fair. I think what's not fair is to close the question. The question is interesting and I think the answers given in the other post are false or, as the OP mentioned, completely insufficient. $\endgroup$
    – CuriousOne
    Dec 21, 2014 at 16:19
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    $\begingroup$ @CuriousOne then post a better answer to the other question. If the questions are really not asking the same thing, such that an answer to this one would not constitute an answer to the other one, then this question should be edited to show exactly what sets it apart from the other question, i.e. what this one is asking that the other one is not, and then it can be considered for reopening. $\endgroup$
    – David Z
    Dec 21, 2014 at 16:21
  • $\begingroup$ @DavidZ: I did post an answer. Given the overwhelming sentiments on the other post I don't feel like going back there and start discussions about it. It seems a little futile. $\endgroup$
    – CuriousOne
    Dec 21, 2014 at 16:24
  • $\begingroup$ OK... my final comment on this one: this paper might help and contains citations of the original publication dealing with the problem. I think the paper makes it obvious that intuition doesn't get one too far: arxiv.org/pdf/gr-qc/0110032v1.pdf $\endgroup$
    – CuriousOne
    Dec 21, 2014 at 17:01

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OK... I can't give a definitive answer to the problem. My intuition tells me that any massive particle or macroscopic mass, boosted high enough, has to look like a black hole. Why? Because it is very hard to see why/how gravity, if we believe in the equivalence principle, should be able to distinguish between kinetic energy and other forms of internal energy (which, by the way, for the case of baryonic matter are also largely kinetic because of relativistic quarks inside the nucleons).

I think the real bummer here is the question what properties a highly boosted Schwarzschild metric really has and what that means to a test particle that gets caught in the near field of such an object.

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  • $\begingroup$ could you provide me some sources to study Schwarzschild Metrics? (I'm not too well versed with General Relativity.) preferably basic beginner stuff! $\endgroup$
    – Hritik Narayan
    Dec 21, 2014 at 15:02
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    $\begingroup$ @HritikNarayan: This is certainly not "beginner stuff". I would love to provide you with a link, but I have not seen a paper like that. Did you try a literature search? $\endgroup$
    – CuriousOne
    Dec 21, 2014 at 15:09
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    $\begingroup$ Thought experiment time: Say there's an object travelling along at high enough velocity to make it a "black hole" ala your intuition. If I fire a light pulse at this object such that it is perpendicular to the object's trajectory and strikes the object at the point of closest approach (I have good timing), what happens? There is no doppler shifting of the light pulse; shouldn't it merely reflect off the side of the object and return to me? If so, how can this be a black hole? $\endgroup$
    – Jim
    Dec 21, 2014 at 15:16
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    $\begingroup$ @Jim: What makes you believe that the light will be reflected? You state implicitly that it will be, but what's the evidence for that? $\endgroup$
    – CuriousOne
    Dec 21, 2014 at 15:21
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    $\begingroup$ @Jim: I am an experimentalist: my only evidence for this case comes from the equivalence principle and thermodynamics. If you can make microscopic black holes and bounce light off of them, good for you. I can't, and if I can't do experiments, I am not using my intuition to guesstimate what the result should be. All I know about equivalence tells me that an outside observer can't tell one form of energy from another. All the theorists that I have heard talking about it seem to think the same. I will go with that. $\endgroup$
    – CuriousOne
    Dec 21, 2014 at 15:29

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