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Poll

Is time part of space, is time part of the mind, is time non-existent ?

Time is part of space
2 (28.6%)
Time is part of the mind.
5 (71.4%)
Time is non-existent.
0 (0%)

Total Members Voted: 7

Author Topic: Where is time?  (Read 9642 times)

Offline yor_on

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Where is time?
« Reply #25 on: 11/06/2010 16:47:49 »
 

Offline Geezer

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« Reply #26 on: 11/06/2010 19:09:50 »
Ha ha! Thanks Yoron.

I may have to put the Atmos on Ebay. It may work better as a barometer than is does as a clock.  :D
 

Offline yor_on

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« Reply #27 on: 22/06/2010 03:38:46 »
Don your idea may be more of a semantic one than a logical.
You assume that time actually can have different temporal 'directions'.

We don't know that, we have no experimental proofs of it, the only thing we have is our 'reversible math' that makes sense in a mathematical fashion. I agree with your concept of 'motion' though as the uncontroversial experimental proof of what we know. That time have one arrow, pointing the same way no matter what frame of reference you exist in.  If time were to stop no thoughts would be there, without those where would that inquisitive mind be? And how would we come to a separation of matter and 'nothing' that we experience. ´Without time there would be nothing to measure and no experimental proofs either.
 

Offline Geezer

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« Reply #28 on: 22/06/2010 04:05:16 »
Don your idea may be more of a semantic one than a logical.
You assume that time actually can have different temporal 'directions'.

We don't know that, we have no experimental proofs of it, the only thing we have is our 'reversible math' that makes sense in a mathematical fashion. I agree with your concept of 'motion' though as the uncontroversial experimental proof of what we know. That time have one arrow, pointing the same way no matter what frame of reference you exist in.  If time were to stop no thoughts would be there, without those where would that inquisitive mind be? And how would we come to a separation of matter and 'nothing' that we experience. ´Without time there would be nothing to measure and no experimental proofs either.

Hi Yoron,

I have a nasty suspicion that entropy ultimately prevents us from reversing time. A lot of the other things might be (conceptually) reversible, but entropy is very difficult to reverse.
 

Offline syhprum

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« Reply #29 on: 22/06/2010 06:40:17 »
Geezer as a technician I am intrigued by the experiment you describe, does your pulse generator, photo transistor and LED have sufficiently rapid rise times to work in the sub nano second region.
 

Offline Geezer

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« Reply #30 on: 22/06/2010 17:48:07 »
Geezer as a technician I am intrigued by the experiment you describe, does your pulse generator, photo transistor and LED have sufficiently rapid rise times to work in the sub nano second region.

Hi Syhprum:

I've never actually done this experiment, but I think it should work. I was extrapolating from observations of digital circuits many years ago where the delays produced by the PCB traces were quite easy to observe and quantify with garden variety scopes of the time. Admittedly, the propagation is on PCBs is only about a third of C.

The pulse width can be large. You just need a sufficient repetition rate to build up a decent image on the scope. Even if the LED and phototransistor are a bit on the slow side, it should be possible to clearly see the delay produced by the greater distance.

The biggest problem might be columnating the light from the LED (an infrared emitter might be better) so that the waveforms were very similar at the two distances. I suppose a way around that would be to use a powerful emitter and do the tests at 900 mm and 1000 mm. Of course, if we used a laser, we could also measure the delay over much greater distances.


 

Offline syhprum

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« Reply #31 on: 22/06/2010 19:07:54 »
Geezer

May I suggest if you ever setup the experiment you use a laser diode and a photo multiplier tube.
To measure the time delay accurately you need a fairly steep rise on the oscilloscope display
 

Offline Geezer

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« Reply #32 on: 22/06/2010 20:04:33 »
Geezer

May I suggest if you ever setup the experiment you use a laser diode and a photo multiplier tube.
To measure the time delay accurately you need a fairly steep rise on the oscilloscope display

Well, yes. The steeper the better, but as long as the slope was not too horribly slow, you could make a reasonable estimate - within maybe 10% or so?

My proposed experiment was a "super economy" version that anyone might set up in their basement. The idea was to demonstrate that light "takes time" to travel distance more than anything else. I would not recommend it as a method for precisely evaluating C  :D
 

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Where is time?
« Reply #32 on: 22/06/2010 20:04:33 »

 

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