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?
Asked
Active
Viewed 110 times
2 Answers
2
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
- 11,450
1
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
- 117,350