Comments about the News in focus article in Nature: Physicists split by Hawking paper

Following is a discussion about the News in focus article in Nature Vol 529 28 January 2016, by David Castelvecchi
In the last paragraph I explain my own opinion.


Almost a month after Stephen Hawking and his colleages posted a paper about black holes online, physicists still cannot agree on what it means.
For the article see
Some support the preprint claim - that it provides a promising way to tackle a conundrum known as the black hole information paradox, which Hawking identified more than 40 years ago.
This sentence does not sound very convincing.
A little further we read:
Hawking discovered that black holes are not truly black and in fact emit some radiation.
Black holes are black by definition only that they do not emit photons i.e. are invisible from the human point of view. That does not exclude that they can not be detected by other means.
According to quantum physics pairs of particles must appear out of quantum fluctuations just outside the event horizon - the BH's point of no return.
The evolution of physical processes is not controlled by any law. Laws are descriptions of these processes.
As such the evolution of BH's has nothing to do with quantum mechanics or an event horizon.
Accordingly to quantum physics, pairs of particles must appear out of quantum fluctuations just outside the event horizon - black holes point of no return.
Suppose this is true. Why should these pairs not spontaneous appear inside our Solar system?
Some of these particles escape the pull of the BH but take a portion of its mass with them, causing the BH to slowly shrink and eventual disappear.
When a BH shrinks slowly it will become vissible?. This whole scenario is rather unlikely
In a paper published in 1976, Hawking pointed out that the outflowing particles - now known as Hawking radiation - would have completely random properties.
The question is what he means. Immediate after something falls and merges with the BH it becomes completely random. The specific physical information is lost. The same as when an object collides with our Sun and melts.
But this result clashes with the laws of physics that say that information like energy is conserved, creating a paradox.
When something collides with our Sun the energy conservation law is maintained. When photons are emitted by our Sun the energy conservation law is maintained.
The same for a BH, assuming something can escape.
The mistake etc.
he and Hawking etc turn to soft particles. These are low-energy versions of photons, hypothetical particles known as particles and other particles.
Gravitons are the same particles we need in order to describe the movements of the planets in Our Solar system. See also Reflection
It follows, they write, that anything falling into a black hole would leave an imprint on these particles.
That is correct. The same when anything falls into the Sun i.e. its mass, its gravitational field increases.
The paper goes on to suggest a mechanism for transferring that information to the BH - which would have to happen for the paradox to be solved.
There is a real issue if there is a paradox in the first place.

"Trick Transfer"

Still, the work is incomplete, A. Ashtekar, says that he finds the way that the authors , transfer the information to the BH - which they call 'soft hair'- unconvincing.
I do not know if he/they mean the no-hair theorem.
Anyway you can not transfer information to the BH. There can be a flow of mass or radiation to the BH, but not something which you call information.
And the authors acknowledge that they do not know how the information would subsequently transfer to the Hawking radiation, a futher necessary step.
Again the word information should be completely skipped.


A blackhole is in a certain sense nothing more of a collection of 1000 sun sized stars combined in one object. The most important physical parameter is that such an object does not emit radiation in the form of photons. As such an hugh object is not visible from human point of view and we call it a black hole.
This name is rather misleading, because it is not a hole. A much better name would be an invisible object or dark object.

According to current accepted understanding such an hugh object has collapsed under its own gravity into one "point" i.e. it is small object.
A BH is not directly visible but that does not mean that their existance can not be inferred. Around the center of our own galaxy there are stars circulating. All these stars indicate the same large mass at the center, which is invisible. i.e. a BH
What this means that a BH is not truely invisible, but can be detected. It can be detected by means of gravitons. This implies that the laws which describe the behaviour of Black Holes should not be based on photons but much more on gravitons.

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Created: 30 March 2014

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