The Fabric of the Cosmos

fabric of the cosmosThe Fabric of the Cosmos, Brian Greene

Even if you don’t know who Brian Greene is, you’ve probably seen or heard him around. He’s done two miniseries for NOVA, and two TED talks. He’s been on NPR’s Science Friday a couple of times. He did a cameo on the Big Bang Theory. And earlier this year he was on Stephen Colbert’s show with a world-record-setting Galilean Cannon. He’s also a professor at Columbia University’s Center of Theoretical Physics. While he talks repeatedly in his book about how time travel is impossible, I assume he’s found some way of developing a time turner in order to accomplish all of this.

Greene’s also written a couple of books, and this was my second time reading his second book, The Fabric of the Cosmos: Space, Time and the Texture of Reality. The Fabric of the Cosmos centers around the fundamental questions of where does everything come from, why does time move in one direction, and just what is everything made of anyway? He’s a patient author, and while I don’t think any layperson reading this will have a deep understanding of all of the different pieces of string theory and why we have all these extra dimensions lying about, I do think he does the best he can without teaching us complex mathematics. Greene also builds up to these theories, starting with Newton and moving through the history of physics and what has brought us to the current theoretical framework.

This book did make me contemplate time quite a bit and, specifically, the changes that occur as one gets older. The first time I read this book, and The Elegant Universe, I remember being fairly blown away by the ideas they contained. The second time around I found myself thinking, “Well, none of this is actually possible. Obviously quantum physics is witchcraft.” I exaggerate slightly, but at a certain point in theoretical physics its hard to see it as pure science anymore. When we’re trying to explain the world in ways that can’t be observed or experimented on, with math that isn’t completed yet and in fact has to be changed up constantly, that one can just add an extra dimension to (string theory had 9 space dimensions and 1 time dimension, then someone united the different theories with M-Theory but to do this you need 10 space dimensions and 1 of time) without substantively altering the theories, and theories predict all sorts of things that by all accounts don’t exist, it’s hard to accept this as the final descriptor. Maybe all off our math is wrong and can only work for classical physics, maybe there’s an as yet unidentified way of truly describing the universe. Maybe we’ve been headed down the wrong path for decades. Maybe we are all holograms?* Now I need to go lie down for a while and watch some House Hunters International until I can purge all of these mind-splitting questions.

In all seriousness, the book is fascinating, but the questions it raises are mind-boggling. I also found myself with a lot of additional questions that I assume there are answers to, or at least have been contemplated since they seem obvious, but the book didn’t address.  I’d love to attend a seminar on all this.  My questions are:

  • How is it possible that particles only ‘decide’ where they are when they are observed, as is the case in quantum physics. I know we’ve shown it’s the case, but don’t they interact with the world constantly? The question Einstein raised about quantum mechanics is, would anyone argue the moon isn’t there when we’re not observing it? But surely even if no human was looking at the moon, it’s being ‘observed’ by birds, gravitons, dark matter, solar radiation, etc. What does the interaction of the rest of the world have to do with quantum mechanics? This must have an answer, but I haven’t seen it.
  • Greene, and other physics explainers I’ve seen, make much of the fact that physics equations work the same forwards in time and backwards in time. Basically, there is no reason, based on the laws of physics, that your egg couldn’t put itself back together and jump back on the counter. Which seems to indicate a basic flaw in the laws of physics to me, but never seems to bother scientists. Greene explains that the big bang caused us to begin with a highly ordered universe, and that the entropy is constantly building, and that’s why we have the arrow of time. But 1) he explained earlier that entropy is just as likely to *have been* than to *be in the future*, so that still doesn’t seem to explain the arrow of time, and 2) even if that explains it for the universe as a whole which is moving to a more disordered state, that still doesn’t explain why it is the case for every single piece of the universe constantly and forever. TL;DR What’s up with time, anyway?
  • Dark matter? Seriously, what is up with that? And now there’s extra unexplained stuff besides dark matter? I’m going back to House Hunters.
  • Greene goes into detail about the potential shapes of the universe (spheres, saddles, or flat) before detailing that it may not matter because the universe is so big, possibly infinite, that it’s more or less flat where we are. Nope, you’ve gotta do better, physicists. We’re trying to determine the shape of dimensions smaller than a Planck length (1.616229 x 10-35 m), an inconceivably small distance, but so-big-it-may-as-well-be-flat is the best we can do for the universe? That doesn’t cut it for me.
  • Despite what I just said, though, that criticism only works if the universe is finite. If its infinite, doesn’t it actually have to be flat? Otherwise, where is the ‘middle’ where it starts to curve for either a saddle shape or a sphere? Is this something that can be answered mathematically, but not pictured? Or does infinite mean flat?

 

I have a lot more questions, too, but they’re more along the lines of how all these extra dimensions fit in, questions I think are still somewhat unanswered, and even if there is an explanation, its only one that exists in theoretical maths^, not anything that can be translated to our world.

Green’s book won’t turn you into a theoretical physicist overnight, but I do think his work is some of the most interesting and accessible on modern physics. Even if it does leave me with more questions and answers. His most recent book, Hidden Reality, explores other dimensions more seriously, so I may have to pick that up. Even if I still think it’s all impossible.

 

*Briefly, the strength of the gravity of a black hole and the amount of entropy don’t correlate with the volume of a black hole, but only with the surface area. Which shouldn’t be the case! But it suggests that at a certain point it’s the ‘projected’ part of the hole that has an effect on its surroundings. This alongside some suggestions that we may actually be a three-dimensional brane wrapped around other dimensions makes it possible that we interact more as holograms than solid beings, a theory Greene thinks has legs. I think the obvious explanation is Elon Musk is right and we’re in a simulation.

^Not an error. I’ve been listening to a lot of British podcasts lately.

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3 Responses

  1. […] The Fabric of the Cosmos, Brian Greene—Greene traces the history of the scientific quest to determine reality and its beginnings from Galileo and Newton and on through modern string theory. It’s fascinating. Also, the difference between discussions at physics conferences and weed intensive college dorms is apparently just how many math equations are used. […]

  2. […] rereading The Fabric of the Cosmos last year I decided I should go back and reread Brian Green’s first book, The Elegant Universe: […]

  3. […] Even Wrong, Peter Woit. I’m fascinated by physics and the search for a theory of everything, as I’ve written about before. And, having just read some critiques of string theory and how it […]

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