Philosophy *sigh*

I was talking to Karl, who sits next to me, this morning and he just tossed off something which is aparently an old phrase but which i had never heard before - What is more accurate, a clock that is an hour off or a clock that is stopped?

I talked it over with my new email thread buddies and we came to the conclusion that the clock that is stopped is the most accurate because at two times a day it is possible to say that the stopped clock is perfectly accurate where as the clock that is slow, or even a normal clock that is 'on time' you can never with any absolute certainty say that it is perfectly accurate!

This then got me thinking. Can a clock ever be perfectly accurate, even a stopped one? In a terry pratchettesque style of poser we started talking about the nature of time. This question, as posed by Terry Pratchett, popped up - Is time infinitely divisible or is there a smallest fraction of time? If time is inifinitely divisible then how is there a past and a future? If it isn't inifinitely divisible does that mean that the smallest fraction of time is a thing? If it is a thing then what is time?

Now i know that we aren't physicists of the highest order, but we all have the internet and we all have brains so i thought that in this topic we could look into the nature of time, with supporting doccuments OR your own (crackpot) theories (don't worry i was baggin my self out there as well since i have a few) and have a bit of fun with another neutral topic.


Now.... Discuss.

Tom wrote:Can a clock ever be perfectly accurate

I would think yes, because time is our way of measuring a nonspatial continuum in which events occur in apparently irreversible succession from the past through the present to the future and since we define it I would think we can build a clock that works exactly with that system...

I think that works...

I like the point but i would note that time is a measurable phenomenon and not a concept invented by humanity and since a clock is an instrument for measuring said phenomenon surely you can say how accurate a clock is at measuring the phenomenon. Since you can say that it is acurate to the nth degree you can also say that it is not accurate by the nth degree. If a clock can be inacurate at measuring time then I would say that most are because, while time may flow at a constant rate (?) a clock is a product of materials that flux and move at a non-constant rate and is therefore flawed.

Thoughts

Why are you assuming that a clock has to measure discreet time instead of continuous

Explain how!

Then again, revising my statement before - Is time a measurable phenomenon and a concept of humanity, or one or the other?

I know there are concepts of time that are purely human like hours, minutes etc. Even days and nights are names given to changeable and situational phenomena. So a clock measures seconds, minutes and hours. Does this mean that, because it is only made to measure the time of mans making that it can be accurate? I suppose so. But when measuring time itself, chopping time into managable pieces rather a clock is measuring time. The number of hours until lunch time, that's man's time. The number of seconds or hours between one definable point in time and then next definable point in time is not. The way we split time isnot important. For instance a metre is a metre. It is a definable distance. This doesn't mean that a 'metre stick' which isn't actually a metre is acurate simply because we say that it is a metre stick.

I was enjoying observing the discussion, but now it seems to have died. So I'll just add this side response.

Tom wrote:Is time infinitely divisible or is there a smallest fraction of time?

Coincidentally, this exact question caught my eye when I was reading some laymen's physics book (the only kind I can read) a while back and the 'answer' stuck in my head because it really interested me. So, apparently, as I understood it, quantumn theories suggest that there is indeed a smallest unit of time (and length!), the planck time. Which was something that totally blew my mind.
http://www.physlink.com/Education/AskExperts/ae281.cfm?CFID=9504688&CFTOKEN=31425804
Althought, according to wikipedia, some observations today raise doubts as to whether or not this is true.

Ah, since I'm here I'll keep going on this topic. Maybe accuracy in time keeping is in reference to the constancy of the rate of time keeping? I think that's how they compare atomic clocks' accuracy—by how regular they keep their rate, I think. Here's some interesting quotes:

"Today, cesium clocks measure frequency with an accuracy of from 2 to 3 parts in 10 to the 14th, i.e. 0.00000000000002 Hz; this corresponds to a time measurement accuracy of 2 nanoseconds per day or one second in 1,400,000 years. It is the most accurate realization of a unit that mankind has yet achieved."

"In 1967, the 13th General Conference on Weights and Measures first defined the International System (SI) unit of time, the second, in terms of atomic time rather than the motion of the Earth. Specifically, a second was defined as the duration of 9,192,631,770 cycles of microwave light absorbed or emitted by the hyperfine transition of cesium-133 atoms in their ground state undisturbed by external fields."
http://tycho.usno.navy.mil/cesium.html

The second one I thought was interesting because it does seem to suggest, to me at least, that our definition of time (and other units) must be grounded on some physical phenomena (unless they're derived from other units) and, more importantly, our ability to measure those phenomena. So, maybe, our inability to perfectly probe down to the most microscopic levels means that clocks can’t be 100% ‘accurate’, in terms of the rate at which they keep time. ...?

That's what i said! WOOP WOOP WOOP!

Andy you know what this means! We AGREE!!!!!!!

I have taken a screen shot of it, and posted it up, to commemorate it.



What a momentous day this has been.

And here I though time was just a guide-line to let us know roughly how much sunlight is left in the day

The heading is "philosophy" so chew on this....

"Everything is in our reach, yet out of our control"

i like to think this ties fate and luck together, rather than trying to seperate the two. We have all heard "Do you believe in luck or fate?" but i say both!

your fate is, if you try to reach, and your luck is when what your reaching for is either gained, lost or left staring you in the face till you try again....

ps i am not an english professor

Hey, Skyman, way to bust out with some more philosophy. I love it. Is all that what you’ve collected throughout your forays into various Eastern mystic/martial arts sects? What was that one... Heart of the Ocean, or something? That is the most awesome name ever. Or is all that philosophy a Skyman original?

I am going to go for an original.

I would tend to agree, mostly because it's Skyman, but partially because of this!

You know, they're called fingers, but I've never seen 'em fing...

Glenjamin wrote: because of this!

Well, Skyman, now you have your avatar. Get to work!

Damn right!

Going back - back - back - back

to an earlier Andy post of 30/09/08.

I was sending this to a mate of mine via email when i realised that i didn't agree with this concept of planck time.

Here is what i wrote

"Remember a while back when we were discussing whether or not there was a smallest fraction of time?

"Here is an interesting answer

"Unfortunately, like much of physics it is only true for physical anomalies (including energy). Which is to say that, although it is true in one sense, that doesn't necessarily make it the absolute truth.

"This is the smallest amount of time for anything to happen, in our universe. They say that everything smaller is irrelevant but that is gibberish to me since, even though nothing can be classed as moving in those moments between one planck time and another, doesn't mean that there isn't the infinite potential for the beginning of movement at any point along that finitely small scale.

http://www.physlink.com/Education/AskExperts/ae281.cfm?CFID=9504688&CFTOKEN=31425804

Andy and diverse others, please shout me down.

Awesome, I love the call-back.

Yeah, the idea of Planck length/time is indeed counterintuitive, like most of physics (i.e. the world). And I certainly don't understand it completely. I, too, thought it didn't make sense (and it may not) when thinking about how if time/space is infinitely divisible then you should always be able to go smaller. But maybe space/time aren't—I don't know if that's what they're arguing, but I'll try say what I understand the proposition to be from when I first encountered it in Brian Greene's book, The Elegant Universe: When you get to a small enough distance, say r, you would think that you could easily get to a smaller distance by simply dividing by 2, namely r/2. BUT, what this particular theory says is that when you operate on such equations (some fancy ones, I imagine) r/2 and 2r operate in exactly the same way! (Which fricken blew my mind!) So that there is no difference between the inverse of any distance of space/time, relative to the Planck measures... I think.

You mention something about "infinite potential" which I didn't really understand and so maybe I missed your point. You might need to clarify, if what I said wasn't appropriate.

Ponder no more... yes that was a Skyman original, thank you Tom.

As for the Avatar! thank you Glen, again.

As for Andy's is any one else getting tired of looking at george cantstandya...?
that face and nipples are too distracting sorry andy..

I believe, and i may be wrong, but that the entire thing comes back to 'limits'. In maths when something gets so small that the, when considered spacially there is practically no difference between the amount and zero then it can be considered zero. It's like touching your fingers together. There is actually a miniscule space between the two fingers, no matter how hard you press them together, yet the distance between, in real terms, can be considered zero.

However i have always thought that is a cop out.

What i meant by infinite potential is this. Lets say you are in the ocean, you are swimming around, having a great time and then you dive down and look horizontally and all you say is blue. Now, at the moment there is nothing there... but due to visibility issues you know that, just beyond the blue there is, potentially, something there. Since it could be anything there is the infinite potential for there to be something there.

In terms of planck time they are saying that, since light speed is the absolute highest speed in the universe (which i don't believe), and since planck space (10 to the minus 20 times the size of a proton) is the smallest thing (which is only cause that is the smallest we can see) then a proton, travelling at the speed of light and traveling one planck unit of space is the smallest amount of time because, and this is the kicker, no other action can happen in that smaller amount of time. In other words any smaller amount of time and the proton cannot be considered moving.

But what about starting to move. If there is planck time then that piece of time has to have a begining and an end. If we create a graph to give that time a visual reference, and then size it up until its, say, the size of a milimeter, then what if another proton, somewhere else, begins its lightspeed journey at the half a milimetre mark?

This is my problem. If something else can happen within that time, even if the specific thing you are measuring (thing not time) cannot move within that piece of time then that piece of time must be further divisible.

Skyman wrote:is any one else getting tired of looking at george cantstandya...?

You don't have to look Skyman. Besides, you're just lucky I cut the picture off above the waist, just because I thought some people would be squeamish.

Tom wrote:However i have always thought that is a cop out.

Yeah, I think I know what you mean. Is it kinda like when you measure the area under a curve via integration, which is essentially cutting the curved space into finer and finer rectangles and adding them up. In high school (and maybe a little still) I was always ‘there’s no way that can be 100% accurate—there’s still a little space left!) But, nevertheless, I’ve been told (I think) that it does indeed = the total volume exactly. And yeah, to do with limits and infinitesimals, I think.

Tom wrote:since light speed is the absolute highest speed in the universe (which i don't believe),

That is interesting. After we’ve finished this discussion maybe we could start a new one on that topic.

Tom wrote:and since planck space (10 to the minus 20 times the size of a proton) is the smallest thing (which is only cause that is the smallest we can see)

Perhaps, I’m not sure. It may be the smallest we can see because it is the smallest unit of space, which is what I think those equations were getting at.

Tom wrote:then a proton, travelling at the speed of light and traveling one planck unit of space is the smallest amount of time because, and this is the kicker, no other action can happen in that smaller amount of time.

Yes, I like how you’ve brought the definition of planck time to depend on planck length; that’s how I understood it.

Tom wrote:then what if another proton, somewhere else, begins its lightspeed journey at the half a milimetre mark?

Hmm. I guess. I’m not really sure. How bout this? What if we drag in special relativity, you know, just so we can add more things that we don’t understand into the mix. So, does your proposal depend on being able to identify clearly when these two separate events occur? Because, and correct me if I’m wrong, does that not conflict with special relativity, in the sense that S.R. tells us that there is no universal instant known as ‘now’.

This doesn’t prove that the planck length works, but I think it would mean we need to come up with another method of going against it.

That is part of this argument that kind of goes against planck time. They are basically saying in planck time that everything started on that one planck moment, then, since then everything works in planck moments, they all work on the same planck moments. As Terry Pratchett put it (and probably various others as well) we are talking about the universal 'tick'. Every 'tick' i.e. planck moment moves everything in the universe forward (spacially) one planck space (if its moving at all... which everything is relatively to everything else)...

But if there is no such thing as 'now' then, first of all how can there be a 'before' and an 'after' (i am sure they explain that Andy, now i am asking you to) and therefore this universal 'tick' thing couldn't work. For the planck thing to work there would have to be a moment where there wasn't a planck time and then there was. If there is no such thing as 'now' then you are saying that there was never any time when this finite piece of time existed, therefore time is inifinitely divisible, so infinite that you can never properly define a single time as 'now'.

wow.. sorry guys that reads like a train wreck but i am writing in concepts for which i am making up my own terminology having never studied them before... I can't make it any better than that.

Tom wrote:i am making up my own terminology

ha! Nah, it’s good.

Tom wrote:They are basically saying in planck time that everything started on that one planck moment

Hmm, yes, that does seem like a good point. In fact, intuitively, even if there wasn’t a smallest unit of time and the universe started at time 0, then it would still seem that the concept of a universal ‘now’ should exist e.g. ~13.5 billion years after t = 0.

BUT, all I can say to that is that if physics has taught us one lesson repeatedly it’s to never trust your common sense, because it is always wrong. So, to continue and address your query about the ‘past’ and ‘future’, I believe, but have never really fully understood, that relativity dictates that there is no universal ‘now’ i.e. we cannot ask the question ‘what is happening on mars right now.’ This is because it makes no sense, and it makes no sense because of the finite speed of light. Previously, when people imagined light (or information, or whatever) could travel with infinite speed (i.e instantly) then the question about ‘now’ could make sense, but no longer. The actual reason behind why it doesn’t make sense I’m a little hazy about, but I believe it is to do with the fact that different observers (which will have different velocities relative to mars, for example, and to each other) will give different results for what they report as happening on mars. I don’t think this is just to do with our limited ability (or lag) to ‘discover’ what is occurring—I think it is an intrinsic property of the universe— but that is beyond this post and beyond my understanding.

So, in terms of a ‘before’ and ‘after’, they still exist in terms of any one observer, but, I think, you are right in suggesting that these terms as having precise universal value are now brought into some doubt. Two observers may differ in their opinions as to whether an event occurred before or after another event provided those interpretations don’t violate the law of cause and effect. I’ll have to check up on that last sentence to make sure.

I don't like that at all. Relativity... yurk. I'll relative yo' mamma!

Why is it that everything in physics is so homocentric! Just because two people see something at different 'times' relative to the actual incident doesn't mean that there isn't a now. Light is a phenomenon that lets us see, time is a phenomenon that lets us move, at one point in time you can say that this happened, then you can say that the people on earth saw it first, then the people on mars (presuming it is coming from the Sun). Light is not the be all and end all of all scientific thought people! Give it up!

"It's like 'the sopranos'.. The sopranos is over dude... get a new show!"

That's another of my favourite quotes of the Pratchmeister - "If its four there, and eight here, does that mean that when 'now' here its not 'now' there?" "It's always now everywhere miss".

(heavily paraphrased because i couldn't find the quote on the net but if you want to look it up it is in the first 50 pages of the thief of time)