Will all objects in the Universe transform into black holes through quantum tunneling?

[Suekdccia]

TL;DR Summary

Considering extremely large timescales, will all objects in the universe transform into black holes?

If I understood it correctly, at enormous timescales into the future, it is theoretically expected that eventually stable massive structures (like white/black dwarfs) will suffer quantum tunneling events that would make small pieces of them slowly turn into black holes that would rapidly decay into photons that would escape [1] [2] [3].

I have two questions:

If this can indeed happen, the black hole would almost immediately evaporate. At that size and Hawking temperature, wouldn't it evaporate into a massive particle? Would it emit the same massive particles as before turning into a micro black hole? [4]

Is it expected that this will be happening to individual particles (e.g. a neutrino)?



[1]: https://en.wikipedia.org/wiki/Future_of_an_expanding_universe

[2]: https://physics.stackexchange.com/q...r-that-could-avoid-matter-decay/819476#819476

[3]: https://math.ucr.edu/home/baez/end.html

[4]: https://astronomy.stackexchange.com/questions/57424/a-couple-of-questions-on-hawking-radiation

 

[PeterDonis]

If this can indeed happen

Which is all speculation since we don't have a good theory of quantum gravity, which is what we would need in order to actually predict (instead of just speculating about) quantum tunnelling of anything into a black hole.

wouldn't it evaporate into a massive particle?

Not just one unless the massive particle were electrically neutral; otherwise it would have to be a particle-antiparticle pair. In either case, the massive particle(s) would not be stable; they would end up decaying to lighter particles and ultimately into radiation, on time scales astronomically shorter than the time scale for Hawking radiation.

 

[Suekdccia]

Not just one unless the massive particle were electrically neutral; otherwise it would have to be a particle-antiparticle pair. In either case, the massive particle(s) would not be stable; they would end up decaying to lighter particles and ultimately into radiation, on time scales astronomically shorter than the time scale for Hawking radiation.

If the particle is a neutrino (which is electrically neutral and does not have any lighter particle to decay into) and tunnels into a black hole, wouldn't that black hole evaporate back into a neutrino? Also considering that according to the Hawking temperarure formula, as the black hole would have a very small mass (the neutrino mass), the temperature would be very high, so wouldn't that mean that it would instantly evaporate into a massive particle with that mass (i.e. a neutrino)?

 

[PeterDonis]

If the particle is a neutrino

Then it can't be produced by itself, it has to be produced as a neutrino-antineutrino pair. I should have said the massive particle can't have any conserved quantum numbers; a neutrino has nonzero lepton number. But actually there are no massive particles I'm aware of that don't have any conserved quantum numbers.

(which is electrically neutral and does not have any lighter particle to decay into)

A neutrino-antineutrino pair can decay into photons.

 

[Suekdccia]

Then it can't be produced by itself, it has to be produced as a neutrino-antineutrino pair.

So if a single neutrino tunnels into a black hole it would evaporate into a neutrino and a anti-neutrino pair? But wouldn't that violate the principle of conservation of energy (as the black hole was formed by the mass of a single neutrino but now it would need twice the energy to form the masses of the neutrino and the anti-neutrino)?

Also, even if objects in extremely long timescales would quantum tunnel into black holes by quantum fluctuations, could there be also some quantum fluctuations that would make new particles to form (using the energy "leftovers" of the universe after heat death)? Or because energy (like electromsgnetic radiation) will be redshifted, there will be a point where this would be impossible?

 

[Nugatory]

Would it emit the same massive particles as before turning into a micro black hole?....
If the particle is a neutrino (which is electrically neutral and does not have any lighter particle to decay into) and tunnels into a black hole, wouldn't that black hole evaporate back into a neutrino?.....
So if a single neutrino tunnels into a black hole it would evaporate into a neutrino and a anti-neutrino pair? But wouldn't that violate the principle of conservation of energy (as the black hole was formed by the mass of a single neutrino but now it would need twice the energy to form the masses of the neutrino and the anti-neutrino)?

If we're going to base our thinking on what is now understood about Hawking radiation (which is far from complete so we're just speculating here), there's no reason why the particles out should be the same as the particles in. Photons can have arbitrarily small energies, so it will always be possible to emit photons without violating violating energy conservation.

 

[Vanadium 50]

We're really piling speculation on top of speculation on top of speculation here. Not only is there no experimental evidence for any of this, there isn't even theory - just guesses about what a theory might say if we actually had one.

 

[PeterDonis]

We're really piling speculation on top of speculation on top of speculation here. Not only is there no experimental evidence for any of this, there isn't even theory - just guesses about what a theory might say if we actually had one.

Indeed. Thread closed.