Confusion about quantum foam, quantum gravity and singularities

[-Sirius-]

Hi all,

I've just finished reading a book about Black holes (Black holes & time warps, by Kip Thorne) and there's something in particular I'm confused about.

One chapter talks about what can possibly be inside the singularity, specifically what would happen to an astronaut as he falls towards a black hole singularity; now I know this topic can never be completely proven however the author lists two possible theories:

1. As the astronaut reaches the singularity, the tidal forces grow infinitely strong and their chaotic oscillations become infinitely rapid. The astronaut dies and the atoms from which his body is made become infinitely and chaotically distorted and mixed - and then, at the moment when everything becomes infinite, space-time ceases to exist.

2. Quantum gravity prevents the above from happening, and instead ruptures the unification of space and time into space-time. It unglues space and time from each other and then destroys time as a concept and destroys the definiteness of space. Space, the sole remaining remnant of what was once a unified space-time, becomes a random, probabilistic froth, like soapsuds. This random, probabilistic froth, is the thing of which the singularity is made.

Now when people reference this "froth/foam" are they referring to the virtual particles popping in and out of existence at the Planck length? Wouldn't they just appear as random dots?

My understanding is the singularity is no longer part of our universe, it is a hole to "hyperspace" - does this mean that these quantum fluctuations happen both in our space-time universe and whatever exists outside it (in the singularity)?

Apologies if this doesn't make any sense or I'm way off, I'm not technical in the matter, just enjoy reading about it.

 

[eljose79]

Hi there,

Thank you for sharing your thoughts and questions about black holes and the singularity. I can understand your confusion and interest in this topic. Let me try to address your concerns and provide some clarity on the theories presented in the book you read.

Firstly, I would like to clarify that the concept of a singularity is a mathematical prediction, and we do not have concrete evidence to prove its existence. That being said, let's explore the two theories mentioned in the book.

The first theory suggests that as an astronaut falls towards the singularity, the tidal forces (the gravitational pull) become infinitely strong, and the chaotic oscillations (irregular movements) become infinitely rapid. This would result in the astronaut's death and the atoms in their body becoming distorted and mixed. At the moment when everything becomes infinite, space-time ceases to exist. This theory is based on the classical understanding of gravity and does not take into account the effects of quantum mechanics. Therefore, it is not a complete picture of what might happen inside a singularity.

The second theory, on the other hand, takes into consideration the effects of quantum mechanics. According to this theory, quantum gravity would prevent the chaotic distortion of the astronaut's body and instead rupture the unification of space and time into space-time. This would result in the destruction of time as a concept and the randomness of space. The singularity would be made of this random, probabilistic froth or foam. To answer your question, this foam is not referring to virtual particles popping in and out of existence. It is a concept that attempts to explain the behavior of space and time at the singularity, where our current understanding of physics breaks down.

You are correct in saying that the singularity is not a part of our universe. It is a hypothetical point where the laws of physics, as we know them, do not apply. As for your question about quantum fluctuations happening both in our universe and outside it, the answer is yes. Quantum fluctuations occur at the subatomic level and are a fundamental aspect of the universe, regardless of whether we are talking about our space-time universe or the singularity.

I hope this helps to clarify some of your questions. Keep exploring and learning about black holes and the singularity, as it is a fascinating and ever-evolving field of study. Thank you for your interest and curiosity.