From what I understand of your book, a white hole is like a black hole in reverse – or as you describe it – like a movie running backwards. Can you explain why they are significant?
We’ve seen black holes and taken pictures of them colliding. We see matter swirling around them and falling into them. But then what? If we fall into them we will be squeezed and writhed but if we say that we have resisted then what will happen next? Do monsters eat what falls into it and do they go to another universe? One can speculate in every way. What I describe in my book is that something very simple happens. Things fall and then they rise again. Like a ball that bounces up from the ground, it follows the same path as it bounces back up, but with less speed. What interested me and my colleagues was that jumping is also predicted by Einstein’s theories. The possibility of things coming out is what we call a white hole. Einstein’s theories did not accommodate a hopping potential, but quantum mechanics [The science and laws governing the subatomic world] will do So we use the 'loop quantum gravity’ equation – the theory of quantum mechanics and gravity – This suggests that the black hole itself jumps and turns into a white hole. If this is true, it implies that space and time undergo 'quantum jumps’ and suggests that we need to change our understanding of what space-time is. Electrons undergo quantum jumps, which make all our electronic devices possible. These are quantum jumps of matter and do nothing to space or time. But here, the shape of space itself is a quantum jump. This indicates that time is no longer this uniform, local thing and makes little 'jumps’. – Like a stretchy rubber band.
Is it possible that our universe emerged from a white hole, one that was previously swallowed by a black hole?
Well, it is the same but there are some differences. A ball going up after bouncing is slower and has less speed and energy. Where did the energy go? It dissipates heat to the ground. Black hole-white-hole transition is similar, which is why studying the transition is complicated. The dissipated energy of a white hole was studied by Stephen Hawking; This is his major contribution to physics. Black holes emit heat or 'Hawking radiation’, and this information is not lost, but can emerge from the 'white hole’. There is an interesting theory that a universe collapsing into a black hole would collapse and create something similar to the Big Bang. We don’t know if that’s the case, but it’s possible. The equations predicting a black and white and a bounce are very similar. So you and I in this universe may have come out of a 'big jump’ from what seems to us like a big bang 14 billion years ago. Towards the end of his life, Stephen Hawking used to say that if you feel like you’re in a black hole, you’re stuck in it forever. Even black holes are not permanent.
How should one understand time in 2023? Is it an abstract but persistent entity—like a marker between two events? Or is it something made of particles, stretchable and compressible, and affected by forces such as gravity?
We have discovered something very real; That time does not go the same for everyone. It seems unusual only because we are not used to it or do not experience it often. If we could travel close to the speed of light, it would be common for us to go on a long journey (at that speed) and come back to find that a younger sibling is now older than you. This is as true as the earth being round. Albert Einstein was the first to suggest that time is not as static as the ticking of a clock, but as flexible as a rubber band. What we need to know is what causes time to stretch randomly in this way.? Is it something like an electric field? Electric and magnetic fields are always around us but we don’t feel them. Similarly, there is a 'time field’ that Einstein called the gravitational field. Einstein imagined us trapped in a giant jellyfish, which is 'time’. In Einstein’s theory, there are no particles of time, but rather a substance called 'spacetime’. Mass distorts spacetime and larger ones are more. Near a black hole, time goes very fast. A person on the edge of one, looking at the Earth, can see a year pass by in a minute. But from Earth, everything moves very, very slowly, and that’s the distortion of time. It is easy to think of space and time as a single entity. It was all Einstein, 110 years ago. But we know that it is finite, and we must also account for quantum effects; Even if they are small. They are important in black holes near the big bang. If we count quantum effects, space is granular. Not continuous and smooth, and this granular aspect of space is time. However this is speculation and the result of what we think should happen when we combine quantum mechanics and gravity. That’s what I’ve been working on all these years. There are (we think) 'time-steps’. Atoms may exist in space but they do not move in space. They are space.