Time Travel discussion

Parallel Worlds: A Journey through Creation, Higher Dimensions, and the Future of the Cosmos by Michio Kaku is our non-fiction choice. We'll be reading and discussing it in June, 2023. It is available in paper, as ebook, and as audiobook.

I'd better go make sure there's no wait list for the ebook....

There's not. And the sample I read, preface and first chapter, are wonderfully engaging. I'm looking forward to the more thorough discussions and then, especially, to the speculations.

I am a little disappointed to realize that the book is relatively 'old.' The author is very excited about WMAP, and is looking forward to Planck...

(Planck was a space observatory operated by the European Space Agency (ESA) from 2009 to 2013. It was an ambitious project that aimed to map the anisotropies of the cosmic microwave background (CMB) at microwave and infrared frequencies, with high sensitivity and small angular resolution. The mission was highly successful and substantially improved upon observations made by the NASA Wilkinson Microwave Anisotropy Probe (WMAP).")

But I am sure that there will still be plenty of interest to try to understand, and to look for more information about.

(Oh, and a few minutes with Google makes it seem to me that the M-theory the author explains is still the best candidate for the explanation of the underlying basis for how things work. But I'm no scientist so if any of you see differently, let us know!)

(Ok, see you back here in a week or so!)

And it's June! I've actually got BotM reads in several other groups, too, so I'm not sure which I'll read first. Probably not this, so feel free to start without me.

First question:

Time Travel means so many different things. Travel to past, or future. A window into past, or future. Observing the past, or changing it. Resiliency of the timeline, or alterations. Etc. What have you heard about what science irl is looking at, and what do you hope that this book deals with?

I really want to read this book but I have been super busy and haven’t had time to read much lately. It might not be until the end of the month until I can get to it.

Fair enough!

I've started it. Just finished chapter one. The author mentions how billions of years from now when the universe is nearly dead if mankind is still around they might use time travel to escape this universe. This is a concept being studied by scientist, as you say, IRL!

I have this checked out from the library, but haven't started it yet.

Chapter 2
I especially like the analogy of the ant who walks across crumpled paper as if drunk. The ant thinks 'mysterious forces pulling me around' but the observer sees 'space-time being warped.'

I'm glad the author is starting back in this relatively 'easy' history of astronomy and cosmology, because even though I've read a lot of popular science books on the topic I still get confused. Too much math underlies what we know, and so we have to just take their word for so much!

I'm making progress. It's still focused on giving the reader a grounding in astrophysics, astronomy, cosmology. I hope to make significantly more progress tomorrow.

"... the artist Bob Miller has asked the riddle: 'how would you suspend 500,000 pounds of water in the air with no visible means of support?' The answer: '(view spoiler)[build a cloud (hide spoiler)].'

OK, so my ebook edition has 333 'pages.' But the text goes only to 284, and the rest is notes, recommended reading, glossary. On p. 84, we're already starting to explore multiverses and alternative universes.

This is not a page-turner. I'm trying to process everything. So far I think I 'get' it, but I can see that changing because I have no idea what is meant by the different designations for different symmetries. The number, sure, but what's the difference between O(3) and SU(3)? What do O and SU mean?

More updates since the book has been published:

First the good news, progress made:

"Physicists have concluded that the detected gravitational waves were produced during the final fraction of a second of the merger of two black holes to produce a single, more massive spinning black hole. This collision of two black holes had been predicted but never observed. Feb 11, 2016, Caltech."

The rest of the stuff they're still working on:

"Gravity is the only force still unexplainable at the quantum level. Its effects on big objects, such as planets or stars, are relatively easy to see, but things get complicated when one tries to understand gravity in the small world of elementary particles. Feb 7, 2020, scitechdaily"

Also, there's new stuff about the cosmological constant, Omega, Lambda, and Einstein's "blunder." Do not bother to try to understand theories older than this book because it's very likely they've been demonstrated to be wrong or at least significantly incomplete with our better imaging technology, advanced math, etc. Wikipedia currently explains:

"However, the cosmological constant remained a subject of theoretical and empirical interest. Empirically, the cosmological data of recent decades strongly suggests that our universe has a positive cosmological constant.[5] The explanation of this small but positive value is a remaining theoretical challenge, the so-called cosmological constant problem."

Onwards to Part Two!

Oh, and the symmetries, my college graduate son says don't worry about the nomenclature.

Been trying to read this one over the last couple weeks, but my interest just isn't there and so I keep wandering back to books I'd rather be reading instead.

I think I would need 6 months to casually work through it. Sorry, but I'm dropping out of this one.

Yeah, I quit too.

Chapter 5 was very readable, interesting (even if not exactly engaging). Fascinating talk about Many Worlds, Quantum Entanglement, Einstein being stubborn, etc. Chapter 6, which I hope to read tomorrow, is about M-theory, which should intrigue if one was intrigued by the popular talk about string theory some years ago.

I think it works better if one can concentrate on it for chunks of time... if I were to casually read it over time I'd have to do too much looking back and rereading. I am making progress by sitting down with it instead of dipping into it.

Part of me wants to give up though, if nobody else is still planning to finish?

Cheryl wrote: "Chapter 5 was very readable, interesting (even if not exactly engaging). Fascinating talk about Many Worlds, Quantum Entanglement, Einstein being stubborn, etc. Chapter 6, which I hope to read tomo..."

I am only on chapter 3, reading about some colorful characters in the land of Astronomy. I have been fascinated by astronomy from when I was a little kid so I can finish this book. Just might take a while. So far not a lot about "time travel" except that when we look at the stars we are actually travelling back in time.

And now I'm losing track. Once he got to the section called 'supersymmetry' there was so much math & jargon I just couldn't untangle it. Skimming carefully I'm now at 'mini black holes' which still have not been found.

The author keeps talking about experimental evidence, but to me it still looks like math explaining math. M-theory can work if we can find something that creates a result that would fit the theory... but the 'thing' wouldn't really be a thing, nor even a phenomenon, at least how he's explaining it.

Ok, other reviewers say the final chapters are going to be more speculative, exploring what we can actually do with what we're learning. They should be more interesting and accessible, I expect.

Cheryl wrote: "And now I'm losing track. Once he got to the section called 'supersymmetry' there was so much math & jargon I just couldn't untangle it. Skimming carefully I'm now at 'mini black holes' which still..."

I'm just about finished with Chapter 7. On pg 226, Kaku mentions LISA (the Laser Interferometer Space Detector) , scheduled to launch in 2020, which might detect gravity waves and rule out a "slow collision between universes" but I see on the NASA website that LISA is now scheduled for 2037.

Ok, I need to push myself. Not tomorrow, probably, big day planned. But soon!

Yeah, poor LISA. ~

I see in my news feed that there's a possibility that a lot of the book could indeed be talking about stuff that's not real, but just math explaining math (my interpretation of arcane physics). I mean, probably not, but I hope they're taking this guy seriously and thinking about reframing the picture from another pov, as he does:

https://www.livescience.com/physics-m...
News
By Robert Lea published about 14 hours ago
New research looking at the cosmological constant problem suggests the expansion of the universe could be an illusion.
...
A blue nebula looks like an eye in this NASA image
...
Astronomers use the light from distant stars, such as the Helix Nebula seen here, to measure the apparent expansion of the universe. New resaerch suggests there may be more to the pictue that we're not seeing. (Image credit: NASA/JPL-Caltech/SSC)
The expansion of the universe could be a mirage, a potentially controversial new study suggests. This rethinking of the cosmos also suggests solutions for the puzzles of dark energy and dark matter, which scientists believe account for around 95% of the universe's total energy and matter but remain shrouded in mystery.

The novel new approach is detailed in a paper published June 2 in the journal Classical and Quantum Gravity, by University of Geneva professor of theoretical physics Lucas Lombriser. ... ...

(... do read further at the link. It's interesting, almost comprehensible to the layperson, short, and not behind a paywall.)

Chapter 8 included 'Goldilocks' and related theories. Not my bag, not TT. Chapter 9 introduces the neutralino, which in 2023 is still hypothetical according to a quick online search. I'm at p. 214 of the 284 in my edition of the main body of text. It's so theoretical and weird that I'm no longer worrying about understanding it all carefully, but trying to get the gist. Chapter 10, The End of Everything, is the first of part 3, Escape into Hyperspace.

I started it three times and gave up.

Thanks for trying!

So, Chapter Ten is indeed about the end of the universe, and Eleven is about what very much more advanced intelligent races might do to escape to other universes. So very speculative it's hardly worth reading, imo. Onwards... I'm almost done now.

Whew. Done. I do indeed think I would have liked it better if I'd read it in the format I find more comfortable, in paper. I'd've followed along better if I'd taken the time to refer to the glossary, too... even though some of the definitions use unfamiliar terms.!

But the conclusion, though it seems to be intended to say something about 'what's the point of all this,' doesn't really say anything.

The main thing that I get out of the book is that vibrating strings, instead of myriad weird particles, might be the foundation of matter and energy. That's the only bit that makes any actual sense to me. The other theories make sense to each other, I can see, but to work out to something we can see outside the theory, well, I'm not convinced.