Julian Barbour on Time

Thanks JustinWell I'm 61, (had to retire at 60), and the idea of going to school to learn some of this stuff crossed my mind. The trouble is I have a volunteer job that involves me most of the week and I'm not prepared to give that up, so I'll content myself with reading books and listening to guys like cavediver. I'll only be able to deal with concepts as I don't have the math however.It is amazing how little people know about this stuff, and what really blows me away is how many aren't even interested. Go figure.

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Everybody is entitled to my opinion.

The only reason for time is so everything does not happen at once.

Try telling that to a photon. (If you can get him to sit still long enough to listen. )

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Everybody is entitled to my opinion.

This is an old topic but I thought I'd see if anyone has anything new to add after reading this article about a man who essentially saw time virtually stop. Time is the way we experience or preceive change. The passage of time seems somehow to be tied in with cour consciousness.Personally I have had time slow down by a remarkable amount during a bicycle accident and other times as well. I am also of the belief that we experience the passage of time differently as we age.Here is the BBC article. The Man Who Saw Time Freeze

Really? I can understand why our perception of time is tied up with our consciousness, but time itself? I find that a more difficult thing to accept, and quite frankly I don't accept it.It is far easier to believe that a man who saw time stop actually has a issue with memory that causes him to believe that. How would you ever be able to tell unless you saw him actually take advantage of slowed time in some way? But do you believe that time is actually changing its rate of passage as you age?

I'll go back to what I quoted in the OP.

quote:

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How does the physics community react to such ideas? Physicists who know Barbour's work agree that it shouldn't be dismissed out of hand. At a physics conference in Spain, Barbour conducted an informal poll. He asked how many of the physicists believed that time would not be a part of a final, complete description of the universe. A majority were inclined to agree.

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Don Page, a cosmologist at the University of Alberta in Edmonton who
frequently collaborates with Stephen Hawking, raised his hand that day. "I think Julian's work clears up a lot of misconceptions," says Page. "Physicists might not need time as much as we might have thought before. He is really questioning the basic nature of time, its nonexistence. You can't make technical advances if you're stuck in a conceptual muddle." Strangely enough, Page feels that Barbour might actually be too conservative. When physicists finally iron out a new theory of the universe, Page suspects that time won't be the only
casualty. "I think space will go too," he says cryptically.

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We know that time varies with speed and gravity. But again time is the way we measure change but we know that depending on those two factors we don't perceive that change simultaneously. Our perceptions are different as to when something happened. But it isn't just a case of memory. His claim is that he could view individual droplets, whereas if time was passing normally it would just look like a normal stream from a shower.I have a clear memory of coming off my bike when the pedal snapped off. I had considerable time to think as I rolled over backwards and the bike went over top me. I remember clearly thinking that I was wearing a white jacket that was going to get dirty and then I casually thought that I'd better put me chin on my chest so that I wouldn't crack my head on the pavement. I have no doubt that in some sense time slowed down for me. Virtually everyone seems to think that as the get older time passes more quickly. I'm inclined to believe that our perceptions do cause a more rapid passage of time as we age. We don't notice in short intervals but we do over longer periods of time. I agree that this is only conjecture but after having read a few books designed for the layman it seems to make sense.Incidentally here is a quote of something that I wrote in this thread in 2005.

quote:

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There is a young girl in our church that just about to start university with the goal of being a research physicist. She has scholarships coming out here ears and has already completed several university courses while still in high school. She just loves the stuff. If she can stick with it I think that she is going into this field at a an incredible time.

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This young woman has now been awarded a full scholarship to study theoretical physics at the The Perimeter Institute. I take credit for it all as I gave her Brian Greene's "The Fabric of the Cosmos" when she was still in high school.

I seem to recall that the common perception is that time seems to pass faster as you get older. It does for me, although it doesn't seem to be a "time of the moment" thing, rather it's a "the last 10 years seemed to go by fast" thing.Hypothesis of why I have this perception:1) When you are 50 (to use a round number), 10 years is 20% of your life, relatively short compared to the 50% of your life at 20 years old.2) It's not so much the "time of your life" as it is the "life of your time". My most recent 10 or so years haven't been particularly productive for me ("haven't done that much"). So, I have the perception that I've lived (say) 2 years worth of life in the last 10 years. Thus it feels like 10 years have passed in what feels like only 2 years. Time is passing fast as life is passing slow.The number 2 perception seems to run counter to the "time flies when you're having fun" concept. I seem to maybe be living some sort of psychological paradox. And I must say, or something like that.Moose

In other word your perception of the passage of time has changed, which begs the question of whether the perception represents a reality specific to you.Hypothesis 1) 10 years is till ten years regardless of how many decades have gone before. I can see the logic but we still measure time by our spatial relation to the sun so I don't see on that basis why our first ten years of life seems to take so much longer than or 5th or 6th ten years.Hypothesis 2) I agree with you "psychological paradox" comment. I don't have any answers but I think that guys like Barbour, Page (from the OP) and others are on the right track.

It's fascinating as far as psychology goes, but I don't know if it tells us anything about physics. To take a parallel case, if a bang to the head in the right (wrong) place can make someone go blind, does that tell us anything about light that we didn't already know?

Yes. And that information did reach his brain through his eyes. I am suggesting a trick of the brain where he has a false memory of actually experiencing time at a slower rate based on this information. Or alternatively even the memory of the droplets being bogus. Those things actually happened. I'm suggesting that this part could be a trick of memory generated after the event and based on the information collected during the event. Perhaps the "slowing" is actually based on biology and not physics.

Nope. Consider the Twin Paradox, where one goes flying in a spaceship near the speed of light while the other stays home. When they get back together, they are not the same age anymore.Your perceived change in the passage of time only affects you, everybody else keeps on keepin' on.Just to share my slow motion story: I was riding a 4-wheeler doing some sick drift turns. I kept going harder and faster until one turn the quad caught traction and flipped. I went flying through the air. Time totally slowed down. I remember right when I went airborne and everything got real slow and I even had time to appreciate the fact that I wasn't on the quad anymore and that I was, in fact, flying through the air. I thought: "Man, this is gonna suck when I hit the ground, I better tuck a bit but don't tense up too tight." Then BAM, I hit the ground and everything speeds back up to normal as I'm rolling down the track.Oh, I got in a head on car crash once too. Saw it coming. That got slowed down as well. I remember feeling my back and butt start to lift up off the seat only for me to go smashing into seat belt I was wearing. I was cognizant enough to notice the weight being lifted off my ass, and then again, BAM, I hit the seat belt and everything speeds back up. It actually took me a few moments to get my wits about me to realize what had just happened, but while I was in the middle of the crash being lifted off the seat, everything was crystal clear... and really really slow.But just because I was seeing everything slow down, doesn't mean that physical reality actually slowed down. It was just my perception of it. Everyone else around me didn't even notice that I have felt time slow, because it didn't actually slow down, itself, it just looked that way to me.

I obviously don't know if it tells us anything about physics or not. I'd suggest that no one knows definitively and it is all a matter of opinion which of course does not mean that all opinions are equally valid.If you google time, physics and consciousness there are a wide variety of opinions. It does seem to me though that we do perceive the world in a particular fashion and physics has told us that in many cases, including time, our perceptions aren't exactly in tune with discoveries made by our scientists.Many of the sites go so far to claim that time is an illusion, and as Don Page says in the OP quote he believes that we will find that both time and space are illusions.With all that in mind it is my highly unqualified belief that ultimately there is a necessary connection between physics and consciousness.

It may be a trick of the brain, but it was his perception unless of course, as you say, it is bogus. However the article does indicate that he is a credible individual. Sure, but it was what happened afterwards in terms of the passage of time that is interesting. Sure, or even both.

It seems to me that you made my point. In the twins paradox they aren't the same age anymore. They have perceived time differently between the time the spaceship left and the time it returned home. Their individual perception of time created their own individual reality.Both of us have experienced situations where time appears to have slowed for us. We perceived time differently than those around us. If we had twinsthen maybe we are now a second or two younger than our twin in the same way that it is explained by the twins paradox.

No, it wasn't their perception of time that created their own individual reality.What changed the spaceship twin's time was how fast he was traveling, but he wouldn't even perceive it as passing at a different rate. It'd seem the same as any other time to him.And the other twin's reality was just like everyone else who wasn't traveling that fast, so it wasn't individual. Nah, you gotta go really fast for that to happen. Our perceptions don't change reality.