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Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by nabla9 on Sunday January 13, 2019 @01:42PM (#18897998)
If I understood the article correctly:

1. Black hole gradually evaporates (Hawking radiation) until it's Plank size.

2. Quantum transition and Plank star.

3. White hole is formed and "the collapsed star is bouncing back".

I Always thought that black hole evaporating energy as Hawking radiation contains all the energy that went into the black hole when the evaporation is complete. This theory assumes that there is energy left.

How is the total energy that went in is distributed between the Hawking radiation and the white hole that follows the evaporation?

Are all white holes equal in size and does Hawking radiation account for the black hole size difference?

Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by enkid on Sunday January 13, 2019 @02:15PM (#18898162)
My understanding is the transition to a white hole exists instead of a singularity at the interior of the black hole, and is therefore hidden by the event horizon. When the event horizon shrinks to the Planck length, the white hole is exposed.
Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by nabla9 on Sunday January 13, 2019 @03:26PM (#18898481)
Yes, but the event horizon shrinks by emitting Hawking radiation, right?

When the white hole is exposed, what it looks like? Is it just hole in the space that does not emit anything? Nothing exits (because Hawking radiation already emitted all of the energy) and nothing can enter.

What is the radius of the white hole?

Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by ianai on Sunday January 13, 2019 @04:46PM (#18898925)
I think Roger Penrose’s explanation here is appropriate, but I don’t know if the similarity between a black holes evaporation and the eventual entropy death of the universe are similar enough: https://youtube.com/watch?v=z2_6h15UCMg.

If so, I think it would mean a Plankt scale black hole would have a significant probability of spontaneously evolving a white hole?

Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by nabla9 on Sunday January 13, 2019 @05:49PM (#18899221)
I just listened Sean Carrol's podcast interview wit Penrose and I think they are different. https://www.preposterousuniverse.com/podcast/2019/01/07/epis...

In the loop quantum gravity there is a bounce because at the lowest level spacetime is discrete and can't be compressed. The big bounce theory of relating to big bang in the loop quantum theory might be similar to the black hole/white hole theory.

In Penrose's theory it's the gravity/mass that is creating time and clumping things together between the big bang and the heat death of the universe (you need mass to create clock and time).

At the beginning of the universe temperature was so high that masses did not matter, at the end of the universe there is no mass, just massless particles (after googol or so when the biggest black holes have evaporated). Massless particles (photon, gluon, graviton) don't experience time so they in a sense fly into the the end of the eternity instantly.

Then there is something geometrical I don't understand and the ends meet and the new universe matches the end of the previous across timeless eon.

Penrose thinks you could perceive the ripples caused by the massive black holes from the last universe in the background radiation of our universe.

Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by ianai on Sunday January 13, 2019 @06:46PM (#18899478)
I think it’s like a duality or equivalence through asymptotic states. Ie old universe becomes timeless energy and new univese.
Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by nabla9 on Sunday January 13, 2019 @07:17PM (#18899611)
LQG and big bounce requires big bang and expansion being followed with contraction of the universe ending with big crunch at the end.

Pernroses CCC (conformal cyclic cosmology) is a big bang followed by an infinite future expansion and timelike infinity.

Re:Black Hole Evolution Traced Out with Loop Quantum Gravity by tylerjwilk00 on Sunday January 13, 2019 @09:52PM (#18900260)
Agreed.

It's seems like it must be either Hawking radiation OR white hole bounce not both.

If Hawking radiation evaporates the black hole then there should be no matter or energy left for white hole to ouput in the future.