Quantum Gravity and time's arrow

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SUMMARY

The discussion centers on the implications of recent findings in quantum gravity, specifically the concept that space-time may behave as if it has two dimensions at small scales, allowing for a distinction between one-dimensional space and time. The participant reflects on Brian Greene's "The Fabric of the Cosmos," questioning the assumption that time behaves the same in both directions. They highlight the complexity of time's behavior in contrast to space, suggesting that classical physics oversimplifies these concepts. The conversation also references Horava's gravity theory, indicating its relevance to the topic.

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  • Understanding of quantum gravity principles
  • Familiarity with space-time concepts
  • Knowledge of Brian Greene's theories in physics
  • Basic grasp of Horava's gravity theory
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  • Research the implications of space-time having two dimensions in quantum gravity
  • Study Brian Greene's "The Fabric of the Cosmos" for deeper insights on time's behavior
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  • Investigate experimental observations related to time's directionality in physics
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Students of physics, researchers in quantum gravity, and anyone interested in the philosophical implications of time and space in modern physics.

hatfarm
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So, a couple weeks ago I read this article. I came here, expecting that someone would probably talk about it (I've been viewing posts here for a while, but became a member only recently). No one, that I could find, has actually talked about it, so I though it would be a good first post for me :). Here's the actual http://arstechnica.com/science/news...-everything-by-ditching-tenet-of-physics.ars" to the article which talks about two papers that utilize the recent finding of space-time behaving as if it has two dimensions at small scales. This allows space to be 1 dimension and time is the other. When you do this, space is the same along all paths, but time isn't (I don't know why, and can't read the actual papers).

This got me thinking about what I was thinking when I first read Brian Greene's "The Fabric of the Cosmos," why does anyone assume that time should be the same forward and backward? Have we ever observed it to be so? I will agree that there are times when it is possible to take a small slice of space-time and not be able to tell the difference forward or backward in time. Like watching a fan move, you wouldn't necessarily know which way time was pointing initially. But this isn't true of all of space-time, space is, but it certainly isn't the same when you put time in there. It seems to me like a way of sticking to classical physics where everything is just a bit easier.

I'm no physicist, actually really just getting started in my physics education, and I'm only going to minor in it, so I don't really know how many people assume that time should be the same both ways. That is something that Brian Greene posited in that book though, and it just struck me as odd, since science is supposed to be used to explain observations and I've never heard of anyone observing that. Perhaps I just misunderstood what he was trying to say, but I just had to ask to make sure.
 
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Wow, can't believe I missed that... sorry. Thanks!
 

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