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So I want to start with a thought experiment imagine one observer moving at a speed of 299 792 457,9999..9 (twenty 9s) assuming c=299 792 458,0 and he emmits a ray of xrays to the moving direction so blue shift equation 10^-10(0,00..1/299 792 458) becomes smaller than the planck length. Our stationary observer should calculate the electro magnetic radiation emmited from our moving observer to have a smaller wavelength than planck length and what quantum physics says a black hole forms but in the moving frame there is no cause for a blackhole to form.What should happen next a blackhole forms or not? If it does what is the speed of the blackhole that is formed what should the moving guy see as the cause of this event?

dababy amogus
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    There is no such thing as a plank length in special relativity. Relativity and quantum mechanics are different theories that are not compatible with each other – silverrahul May 17 '21 at 09:00
  • but like just simple question what happens when we do this experiment – dababy amogus May 17 '21 at 09:55
  • @silverrahul That's not correct. You're thinking of GR. – BioPhysicist May 17 '21 at 11:40
  • ...and what quantum physics says a black hole forms can you give a reference to this? – BioPhysicist May 17 '21 at 12:09
  • @BioPhysicist Sir first of all I am just a 16 yo physics enthusiast sorry if I miss anything :) but I have read and heard a lot about when the wavelength of the light is shorter than the planck length it becomes a "kugelblitz" – dababy amogus May 17 '21 at 15:09
  • A single particle does not become a black hole just because there are inertial frames in which it has arbitrarily large energy. – G. Smith May 17 '21 at 17:17
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    Please specify units for all dimensional quantities. 299792458 is not a speed and 10^-10(0,00..1/299 792 458) is not a length. – G. Smith May 17 '21 at 17:20
  • Related questions: https://physics.stackexchange.com/questions/62390/does-non-mass-energy-generate-a-gravitational-field, https://physics.stackexchange.com/questions/37839/can-a-single-particle-create-a-black-hole – G. Smith May 17 '21 at 17:28
  • @G. Smith so if it does not form a black hole what happens to the particle it keeps on going with its shorter than planck length wavelength? Also if in moving frame the x rays (in stationary frame our "impossible" light) are concentrated to a single point that would not form a blackhole in moving frame but it would in stationary frame. What would be the cause for this effect in the moving frame. – dababy amogus May 17 '21 at 17:51
  • Isn't this how general relativity works "if I am stationary why this light curves that way? Yeah yeah of course there is a gravitational field that causes the time to change flow speed and the space to curve that curve in space causes the light to bend that way." – dababy amogus May 17 '21 at 17:54
  • Comments are not the place to ask new questions. – G. Smith May 17 '21 at 17:56
  • "Wait if I am not in motion and they are the moving boys why that black hole appeared there for no reason!? Oh yeah dark matter?" - the guy who moves at near light speed and shines a light – dababy amogus May 17 '21 at 17:56

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No, quantum physics does not say a black hole forms. Black hole formation is described by general relativity, not quantum physics, and general relativity has no notion of the planck length. Black holes are not expected to form because of any frame dependent notion like the frequency of a photon: if a black hole is to form, it must be observed as such by all observers regardless of their relative velocities.

For that matter, while the planck length is a "natural length", we have no real evidence that there's anything special about it. There are speculative ideas that suggest new physics at the planck scale, but these are just speculation. It's entirely possible that the planck length is just another length like any other.

Eric Smith
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Our stationary observer should calculate the electro magnetic radiation emmited from our moving observer to have a smaller wavelength than planck length and what quantum physics says a black hole forms

Neither quantum physics nor general relativity say this.

There is currently no quantum theory of gravity so quantum physics is silent on gravitational phenomena like the formation of black holes. The most you can do is a semi-classical approximation where the quantum phenomena unfold on a non-dynamic background metric.

For general relativity the appropriate solution for a high energy pulse of light would be an Aichelburg Sexl Ultraboost. This is not a black hole and does not have an event horizon regardless of how high energy the pulse of light has. Even if the energy density is very high, the momentum density is similarly very high and thus the solution is not a black hole.

in the moving frame there is no cause for a blackhole to form

Yes, and there is no cause for a black hole to form in the stationary frame either. Nor any other frame.

Dale
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