Loop quantum gravity and string theory: book recommendation

[DeltaV]

Hi Folks,

Looking for a recent book that covers both of these theories. I've been poking around on Amazon and elsewhere, and have seen books on both subjects from various authors that support one theory or the other. But I don't seem to be able to find a guide that presents a good overview of all the most recent updates/refinements to these theories, and a balanced analysis of the "for and against" for each.

Any suggestions?

 

[tinkerdan]

Loop Quantum Gravity for Everyone: Gambini, Rodolfo, Pullin, Jorge: 9789811211959: Amazon.com: Books

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If you are like me start with these.

Why Does E=mc2? (And Why Should We Care?): Cox, Brian, Forshaw, Jeff: 9780306817588: Amazon.com: Books

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The Quantum Universe (And Why Anything That Can Happen, Does): Cox, Brian, Forshaw, Jeff: 9780306819643: Amazon.com: Books

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to help decide if you want to even try to conquer the maths involved.

 

[DeltaV]

I really liked Why Does E=MC2? and I second your recommendation. Doesn't really go into string
theory or quantum gravity though.

It looks like The Quantum Universe covers a lot of the same ground as Beyond Weird by Philip Ball, which I
also enjoyed.

I've found a couple of older books that look like they give an overview of string theory and quantum gravity, but
both are pre-2010. Hmmm. Based on what I am seeing, it looks like string theory is losing ground. Anyway, if I
find anything, I'll post it here.

 

[DeltaV]

While looking at cosmology books at the local library, I came across The Electric Sky (2006) by Donald E. Scott.

Interesting book that challenges a number of standard theories of cosmology, using electrodynamics to explain many of the observable phenomena of, not just the sun, but of the galaxy and even of the universe.

He points out that 99% of the universe is made up of low density clouds of ions and electrons. This electric plasma, by its very nature, has electromagnetic characteristics, including magnetic fields that generate current. Accordingly, some of the words used in popular science on cosmology are not really exact. For example, in many cases the use of 'gas' in astrophysics is incorrect; it should be 'plasma'. Similarly the so-called 'solar wind' is a stream of plasma emitted by the sun.

The author's main point is that most of the energy of the sun is created by electromagnetic forces, not fusion. Thus there are no "missing" neutrinos that have to be explained away by handwavium. And those same electromagnetic forces explain many of the phenomena of the sun that the standard fusion model cannot.

Finally there is also a chapter that challenges the common explanation of the red-shift of spatial objects, based on the observations of Dr Halton Arp, an astronomer (who I gather is a bit of a black sheep in the US astrophysics community). Intriguing stuff there. Things are not quite what they seem to be.

This got me wondering if there are alternate paths of research that should be looked at, but are not getting the attention or the funding because all the money is being thrown at one or two main stream theories.

I still haven't found a single book that has an overview of all of the main cosmological theories (and I guess the plasma theory could be added to the list). But a copy of Carlo Rovelli's Reality is Not What It Seems has just arrived in the post.

 

[hitmouse]

While looking at cosmology books at the local library, I came across The Electric Sky (2006) by Donald E. Scott.

Interesting book that challenges a number of standard theories of cosmology, using electrodynamics to explain many of the observable phenomena of, not just the sun, but of the galaxy and even of the universe.

He points out that 99% of the universe is made up of low density clouds of ions and electrons. This electric plasma, by its very nature, has electromagnetic characteristics, including magnetic fields that generate current. Accordingly, some of the words used in popular science on cosmology are not really exact. For example, in many cases the use of 'gas' in astrophysics is incorrect; it should be 'plasma'. Similarly the so-called 'solar wind' is a stream of plasma emitted by the sun.

The author's main point is that most of the energy of the sun is created by electromagnetic forces, not fusion. Thus there are no "missing" neutrinos that have to be explained away by handwavium. And those same electromagnetic forces explain many of the phenomena of the sun that the standard fusion model cannot.

Finally there is also a chapter that challenges the common explanation of the red-shift of spatial objects, based on the observations of Dr Halton Arp, an astronomer (who I gather is a bit of a black sheep in the US astrophysics community). Intriguing stuff there. Things are not quite what they seem to be.

This got me wondering if there are alternate paths of research that should be looked at, but are not getting the attention or the funding because all the money is being thrown at one or two main stream theories.

I still haven't found a single book that has an overview of all of the main cosmological theories (and I guess the plasma theory could be added to the list). But a copy of Carlo Rovelli's Reality is Not What It Seems has just arrived in the post.

Plasma Cosmology is a bit fringe, to say the least.

 

[Venusian Broon]

Plasma Cosmology is a bit fringe, to say the least.

Yeah some of it's predictions are fundamentally at odds with what we've observed, the Cosmic Background Radation, for example - data collected by WMAP and the Planck Satellite over the period 2000-2013 were sensitive enough to show that Plasma Cosmology can't (yet?) explain it. Thus to be fair, a book written in 2006 about it would not have access to this data, so perhaps there was some wiggle room when the author was writing it.

However there are other glaring issues, such as light nuclei genesis in the early universe and a bunch of others.

So I agree, pretty fringe at the moment. There are other alternatives that deserve more scrutiny I'm sure.

 

[DeltaV]

I came across a point by point rebuttal of most of the main ideas of The Electric Sky, complete with supporting references. And as Venusian Broon points out, we've learned a lot more over the last 15 years or so. Still, it was interesting. I know a lot more about the sun now than I did a week or so ago, which is a good thing! Now, after that little detour, time to turn my attention to quantum gravity...

 

[Matteo]

Michio Kaku has written some books on string theory but think they pre-date 2010.

 

[Brian G Turner]

I came across a point by point rebuttal of most of the main ideas of The Electric Sky, complete with supporting references.

Would be interesting if there's a link to that.

 

[DeltaV]

Would be interesting if there's a link to that.

Here you go:

On the "Electric Sun" Hypothesis

This dates from 2001, and is a rebuttal to the points on Scott's website at the time. The book Electric Sky dates from 2006. I didn't look for counter counter-arguments from the electric sun folks.


I've also just finished reading Astrophysics for People in a Hurry 2017 Nell de Grasse Tyson

Easy-to-read general overview of astrophysics today. The author is a firm believer that dark matter and dark energy explain some of the apparent mysteries of astrophysics. This book doesn't discuss quantum physics or get into the theories of quantum gravity or string theory.

Two interesting tidbits: I tip my hat to Mr Grote Reber, who in 1938 built a thirty-foot metal-dish radio in his backyard and spent five years making low-resolution radio wave maps of the sky. Mr Reber was an amateur radio operator, and for years he was the only radio astronomer in the world.

I was also interested to learn that approximately one thousand tons of rocks from Mars land on Earth every year. These were ejected eons ago by asteroid impacts on Mars. I had no idea the quantity was that high.

I have on my to-read pile Reality is Not What it Seems by Carlo Rovelli and Three Roads to Quantum Gravity by Lee Smolin (which dates from 2001 unfortunately). I see that Smolin has since written other books on the string theory controversy. Has anybody read any of his later books?

I also saw that the annual Economist book review for 2020 lists The End of Everything (Astrophysically Speaking) by Katie Mack. Any opinions on this book?

 

[DeltaV]

Just finished Three Roads to Quantum Gravity by Lee Smolin. The three roads are 1) black hole thermodynamics (which is more of a stepping stone), 2) loop quantum gravity and 3) string theory. The author does a reasonable job of describing the development of each theory, and their respective problems. Although he states the book is for the layman, some knowledge of quantum mechanics will come in handy.

What is interesting is that all three 'roads' have as a foundation that space is made up of discrete units (on the Planck scale, so extremely small). The author believes that loop quantum gravity and string theory are each part of a single theory; both have been used to accurately describe the behavior of black hole thermodynamics (although at the time this book was written, the methods applied to different types of black holes).

For the basics of black hole thermodynamics, I would recommend A Brief History of Time as there are two good chapters that explain the subject quite well. The author finishes up with a commentary on the M String Theory, which is further elaborated by Michio Kaku in his book Parallel Worlds.

I can't say that every part of Three Roads is an easy read; there are certainly a couple of challenging chapters. As well, I made a mistake when I bought this book (from a used book seller). Somehow I managed to get the date wrong of a book I was looking for. Three Roads was published in 2001, and I was looking for a later book. But, overall, it does give a good snapshot at that time period, and I liked the fact that it compared the two leading theories (at least at that time).