What Are the Limitations and Possibilities of Measuring Time?

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Discussion Overview

The discussion revolves around the limitations and possibilities of measuring time, exploring concepts such as the Planck time and length, the quantization of time, and the nature of time in relation to physical theories like relativity and quantum mechanics. Participants share various perspectives on whether time can be considered quantized and the implications of current scientific theories.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant suggests that time is only measurable relative to a progression or regression of something, proposing that the shortest measurable time is the Planck time, derived from the Planck length and the speed of light.
  • Another participant questions the validity of the Planck length as the shortest possible length, noting that without a theory of quantum gravity, the existence of a minimum length remains uncertain.
  • A different viewpoint argues against the quantization of time, suggesting that time is a human construct based on the observation of repetitive events, and that it does not necessarily follow the quantization seen in energy.
  • Some participants discuss the implications of Einstein's relativity, proposing that time may be perceived differently based on relative motion, and that time could be an illusion separate from energy and measurement.
  • There is mention of Julian Barbour's work on timelessness, indicating that some scientists are considering the idea that time itself may not be fundamental.
  • One participant emphasizes the importance of mathematics in discussing physics, particularly in relation to concepts like the quantization of angular momentum and the nature of time in relativity.

Areas of Agreement / Disagreement

Participants express a range of views on the nature of time, with no consensus on whether time is quantized or if the Planck length is the shortest possible length. The discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

Participants acknowledge the lack of a theory of quantum gravity, which limits definitive conclusions about the nature of time and its measurement. There are also references to the complexity of concepts like global time in relativity and the relationship between time and physical processes.

  • #31
Meselwulf said:
Energy and temperatures are related... what about the background TEMPERATURES OF SPACE?

This is made up of quantized photon energy.

The interaction is quantized through photons. The temperature itself is not quantized.

Meselwulf said:
The BASIC temperature of a system vibrates at

1/2 \hbar \omega

And how does that support your claim that temperature is quantized?
 
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  • #32
Drakkith said:
The interaction is quantized through photons. The temperature itself is not quantized.



And how does that support your claim that temperature is quantized?

The background temperature was given this name for a reason. You want to talk about background temperatures, then you must understand this is the least minimal action of energy a system can take AND IS A TEMPERATURE.
 
  • #33
Meselwulf said:
The background temperature was given this name for a reason. You want to talk about background temperatures, then you must understand this is the least minimal action of energy a system can take AND IS A TEMPERATURE.

That's nice, but I don't see how this answers or explains anything. It might help if you actually attempted to explain yourself a bit more.
 
  • #34
Drakkith said:
That's nice, but I don't see how this answers or explains anything. It might help if you actually attempted to explain yourself a bit more.

The background temperature can take a minimal value of 1/2 hbar omega. All systems can take this lowest energy at the quantized level, it is known as zero point energy.
 
  • #35
Meselwulf said:
The background temperature can take a minimal value of 1/2 hbar omega. All systems can take this lowest energy at the quantized level, it is known as zero point energy.

Let's say I have an object in thermal equilibrium with the background. The object emits a photon and loses that energy. Is it not in a lower energy state before it absorbs one from the background?
 
  • #36
Drakkith said:
Let's say I have an object in thermal equilibrium with the background. The object emits a photon and loses that energy. Is it not in a lower energy state before it absorbs one from the background?

Never will.
 
  • #37
Meselwulf said:
Never will.

It never will what?
 
  • #38
Not when we are talking about the least action of a particle. The zero point energy means it cannot go below that temperature, it is simply a kinetic term.
 
  • #39
Meselwulf said:
Not when we are talking about the least action of a particle. The zero point energy means it cannot go below that temperature, it is simply a kinetic term.

I'm talking about an object in equilibrium with the background emitting a photon and then absorbing one. Will that object be in a less energetic state between the emission and absorption or not?
 
  • #40
Drakkith said:
I'm talking about an object in equilibrium with the background emitting a photon and then absorbing one. Will that object be in a less energetic state between the emission and absorption or not?

No, as I said, it will never be less or more, it will always vibrate at the same frequency, regardless of your set-up.
 
  • #41
Meselwulf said:
No, as I said, it will never be less or more, it will always vibrate at the same frequency, regardless of your set-up.

And if that object is something like a brick, not a single particle?
 
  • #42
Your least temperature will always be a zero point. If you add energy then obviously it is not your least action. In that case... we are not talking about zero point any more.
 
  • #43
Drakkith said:
And if that object is something like a brick, not a single particle?

Do you know anything about the difference between... quantized states and those which are macroscopic?
 
  • #44
Hold on I think we had a misunderstanding. Are you saying the CMB is a zero point? Or are you saying that the background temperature, any background temperature, can have a minimal energy level? I thought you were saying the former.
 
  • #45
Drakkith said:
Hold on I think we had a misunderstanding. Are you saying the CMB is a zero point? Or are you saying that the background temperature, any background temperature, can have a minimal energy level? I thought you were saying the former.

The latter.
 
  • #46
However, the CMB is a background temperature... It can reach a minimal temperature, hence... the ZPEF.
 
  • #47
Meselwulf said:
The latter.

Ok, I agree with that. But I don't see how that means that temperature is quantized. Perhaps we have a different idea of what that means. I take it to mean that the energy values can only be certain numbers. AKA you can move between 5.001 and 5.002 k, but not 5.001 and 5.0011 k. (Just an example) What exactly do you mean?
 
  • #48
Because, again... the back ground temperature is basically... radiation, which may reach the minimal state, a zero point.
 
  • #49
when quantized
 
  • #50
Meselwulf, please explain exactly what you mean when you say temperature is quantized.
 
  • #51
Drakkith said:
Meselwulf, please explain exactly what you mean when you say temperature is quantized.

What is the simplest vibration of energy? What makes temperatures? Can a system be a simple vibration?
 
  • #52
Temperatures in macroscopic systems are measured by how fast kinetic fluctuations are moving in that system. If ZPEF is your lowest state, how much more quantized can a temperature be?
 
  • #53
We aren't talking about a Planck Temperature here, this is something completely different.
 
  • #54
That is a very very high temperature, I don't even see how that can be considered ''quantized.''
 
  • #55
However, there is one exception, and that is a Planck Particle which does have a Planck Temperature which ... is arguably a quantized black hole. But that's a whole new ball game.
 
  • #56
I will continue this tomorrow, I need to go.
 
  • #57
Meselwulf said:
What is the simplest vibration of energy?

Energy cannot vibrate, it is not an object.

What makes temperatures?

Temperature is a measure of the average kinetic, rotational, and vibrational energy of a material. In cases such as the CMB, we say it has a temperature but in reality we mean that an object at 2.725 k emitting radiation will emit an identical spectrum. An object in thermal equilibrium with the CMB would remain at 2.725 k.

Can a system be a simple vibration?

A system can HAVE a simple vibration, but the vibration itself is not a system.
 
  • #58
Drakkith said:
Energy cannot vibrate, it is not an object.



Temperature is a measure of the average kinetic, rotational, and vibrational energy of a material. In cases such as the CMB, we say it has a temperature but in reality we mean that an object at 2.725 k emitting radiation will emit an identical spectrum. An object in thermal equilibrium with the CMB would remain at 2.725 k.



A system can HAVE a simple vibration, but the vibration itself is not a system.

A quantum system, a zero point fluctuation is a vibration of energy.

Go read wiki because I am tired of discussing this with you. Nothing I have said is wrong, a fluctuation is a vibrational energy.
 
  • #59
Meselwulf said:
A quantum system, a zero point fluctuation is a vibration of energy.

Go read wiki because I am tired of discussing this with you. Nothing I have said is wrong, a fluctuation is a vibrational energy.

No, that is incorrect. Unfortunately popular descriptions of many things in science are grossly misleading. Nothing is actually fluctuating when a system is in its ground state. Read the following quote from here: http://van.physics.illinois.edu/qa/listing.php?id=1256
It's misleading to say that large fluctuations 'are occurring' in that lowest state, although scientists often use sloppy phrases like that. The system is just sitting in a state, which happens not to have definite values of position and momentum. It's not true, however, to say that its position and momentum are changing in any way. That language comes from inconsistent attempts to force quantum facts into classical descriptions.

Energy is not something physical, it is not tangible, and it cannot undergo fluctuations. Energy is simply the ability to do work. Even a photon is not energy, it is an interaction of an electromagnetic wave with matter. The wave can do work, thus it carries energy with it, but it is not energy itself. Such a phrase doesn't even have any meaning, much like saying a moving electron is "velocity itself".
 
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  • #60
Meselwulf said:
Sure... time may have existed before man
If time may have existed before man then obviously time cannot be man made.
 
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