Quantum fluctuations and Spacetime

[DonSmith]

Hi there. I am a layman, and I have a question.

As far as I have gathered, the prevalent view in cosmology is that the universe appeared as a result of the Big Bang, which in turn occurred due to expansion of singularity. Ok.

Some go further and propose that singularity appeared through quantum fluctuation. Herein lies my question. Assuming there was no spacetime 'before' the Big Bang, where did these quantum fluctuations happen? In a vacuum that preceded spacetime? I always thought that even vacuum had to be in space.

PS: since we're on the topic, I'd also appreciate if you could throw in some recommendation of a pop-physics book which deals with these questions. I have read brief history of time, long ago, but that's about it.

 

[mathman]

Present day theory has a pretty good idea of what happened after the big bang. The big bang itself is still open to many theories.

 

[edgepflow]

For the origin of the quantum fluctuation universe, see Edward Tryon, "Is the Universe a Vacuum Fluctuation?" written in 1973.

For a good pop-physics book, try Alex Vilenkin's book "Many Worlds in One"

 

[DonSmith]

Thanks a lot.

 

[sardar]

Hello there. Your question is a very interesting one, and it touches on some complex and fascinating theories in cosmology and quantum physics. Let me try to address it as best I can.

First, let's talk about quantum fluctuations. These are tiny, random fluctuations in energy that occur at the quantum level. In the early universe, these fluctuations were likely extremely small, but as the universe expanded and cooled, they became more significant and eventually led to the formation of matter and the structure of the universe as we know it.

Now, as for where these fluctuations happened, that's where things get a bit tricky. The concept of spacetime as we understand it breaks down at the singularity of the Big Bang. This means that our current understanding of space and time may not apply in that extreme environment. Some theories suggest that the singularity may have existed in a state of quantum foam, where the laws of physics as we know them may not have been applicable. This is where the quantum fluctuations may have occurred, outside of our traditional understanding of spacetime.

As for a recommendation for a pop-physics book that delves into these concepts, I would suggest "The Elegant Universe" by Brian Greene. It covers a wide range of topics in modern physics, including quantum mechanics, general relativity, and the concept of spacetime. It's a great read for anyone interested in these complex and mind-bending ideas.

I hope this helps to answer your question. The origins of the universe and the nature of space and time are still areas of ongoing research and debate, so it's natural to have questions and curiosity about them. Keep exploring and learning, and who knows, maybe someday you'll contribute to our understanding of these fascinating concepts.