Physics question pertinent to global warming

[Crick]

Having to do with radiative heat transfer

Let's start with Wikipedia:

Radiation
Thermal radiation occurs through a vacuum or any transparentmedium (solid orfluid). It is the transfer of energy by means of photons inelectromagnetic wavesgoverned by the same laws.[14]Earth's radiation balance depends on the incoming and the outgoing thermal radiation, Earth's energy budget. Anthropogenicperturbations in the climate system, are responsible for a positive radiative forcingwhich reduces the net longwave radiation loss out to Space.

Thermal radiation is energy emitted by matter as electromagnetic waves, due to the pool of thermal energy in all matter with a temperature above absolute zero. Thermal radiation propagates without the presence of matter through the vacuum of space.[15]

Thermal radiation is a direct result of the random movements of atoms and molecules in matter. Since these atoms and molecules are composed of charged particles (protons and electrons), their movement results in the emission ofelectromagnetic radiation, which carries energy away from the surface.

The Stefan-Boltzmann equation, which describes the rate of transfer of radiant energy, is as follows for an object in a vacuum :

For radiative transfer between two objects, the equation is as follows:

where Q is the rate of heat transfer, ε is the emissivity (unity for a black body), σ is the Stefan-Boltzmann constant, and T is the absolute temperature (in Kelvin or Rankine). Radiation is typically only important for very hot objects, or for objects with a large temperature difference.

Radiation from the sun, or solar radiation, can be harvested for heat and power.[16]Unlike conductive and convective forms of heat transfer, thermal radiation can be concentrated in a small spot by using reflecting mirrors, which is exploited inconcentrating solar power generation.[17] For example, the sunlight reflected from mirrors heats the PS10 solar power tower and during the day it can heat water to 285 °C (545 °F).
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I know Todd had these equations up here before. I'm just curious how you explain the TWO TEMPERATURES in the equation for heat transfer between two objects. I would have thought that in your world, the difference between the two temperatures would simply act as some sort of gate. Like: If Ta>Tb then [Q=sigma deltaTa] else [Q=0]. Right? But that's NOT what they've got there. What they have there shows that the heat transfer actually taking place is the net, the algebraic sum, of the heat being transferred from hot to cold and from cold to hot.

I believe Todd pointed this one out to you as well. Let's say I have three cannonballs. One is 100C, the next is 50C. The last one is 0C. I have an insulated chamber in which I can place two of these at a time and monitor what their temperatures do. I first put the 100C in with the 50C. The first ball cools while the second ball warms up. I take them out and bring the 100C ball back up to temperature and then put it in with the 0C ball. Again, the hot ball cools and the cool ball warms.

What's the difference? Ta^4-Tb^4 is larger in the second case than in the first. So Q, the rate of exchange, the rate of heat transfer is much faster in the second case than in the first. The RATE at which heat is transferred is dependent on the magnitude of the temperature DIFFERENCE. The total transfer is the NET result of transfer taking place in BOTH DIRECTIONS. What you have been suggesting is that the hot ball will radiate as single-body Stefen-Boltzman says 100C will radiate and the second ball will not radiate at all. There would be no difference in the heat transfer rate in the two cases.


Do you disagree?

 

[SSDD]

Note the equation for radiation between two objects depicts a one way gross flow of energy...not a two way flow...just like the second law says. How wild is that?

An equation depicting two way energy flow would look like this:

 

[Crick]

If you're going to change and add variables, you might want to define them. However, it's good to see you seem to remember how to use the Distributive Law you learned in the seventh grade.

Be that as it may, your equation has nonzero terms for flows in both directions. How does that happen if, as you contend, it is impossible to radiate towards a warmer object?

 

[SSDD]

If you're going to change and add variables, you might want to define them. However, it's good to see you seem to remember how to use the Distributive Law you learned in the seventh grade.

Be that as it may, your equation has nonzero terms for flows in both directions. How does that happen if, as you contend, it is impossible to radiate towards a warmer object?

The actual SB equation describes a one way energy flow...sorry that you can't see that. That's one of the problems with attempting to pose as someone who should know such things...

The actual SB equation describes energy flow from a radiator being determined by the difference between its own temperature and the other object....it is a one way process. As I pointed out, if it depicted a two way flow the equation would look different.

You can't win this crick because you are wrong to begin with....you believe in two way energy flow even though it is nothing but a mathematical construct and has never been observed in the natural world....

 

[Crick]

I was referring to YOUR version which you introduced thusly:

An equation depicting two way energy flow would look like this:

which, as I stated, has nonzero terms for radiation in BOTH directions.

 

[Crick]

What hasn't been observed is your magic.

 

[SSDD]

I was referring to YOUR version which you introduced thusly:

An equation depicting two way energy flow would look like this:

which, as I stated, has nonzero terms for radiation in BOTH directions.

That is not my formula...it is, as I stated what an equation that describes a two way flow would look like...that is not the SB equation which describes a one way energy flow.

 

[SSDD]

What hasn't been observed is your magic.

What hasn't been observed...or measured is energy moving spontaneously from a cool object to a warm object.

 

[SSDD]

What hasn't been observed is your magic.

What hasn't been observed...or measured is energy moving spontaneously from a cool object to a warm object.

Tell me crick...do you think science knows precisely what is going on at the sub atomic level?...Do you think that as science advances, that what will be found is precisely what we imagine today is what is happening or do you think that as with most science, new observation tends to simply overturn and render useless what we thought we knew?

 

[IanC]

The change from classical physics to QM added a new layer of complexity, it did not radically change the macroscopic details of low speed non instantaneous conditions. There may well be another layer that replaces QM but it will give results that approximate QM very closely.

 

[IanC]

Planck curves are simply histograms of the type of energy being radiated from an object. The range is dependent on the temperature. Two objects that vary by only 100C will have nearly identical ranges. At any one instant of time the cooler one may emit a higher energy photon than the warmer one, giving a transient period where the energy flow is against the temp gradient. Because the warmer object on average emits higher energy photons, and more of them, this scenario is rare but not impossible. Over any time frames larger than nanoseconds the law of large numbers enforces the SLoD. Statistics rule the macroscopic world.

 

[Crick]

"Statistics rule the macroscopic world"... sounds vaguely familiar.

 

[SSDD]

The change from classical physics to QM added a new layer of complexity, it did not radically change the macroscopic details of low speed non instantaneous conditions. There may well be another layer that replaces QM but it will give results that approximate QM very closely.

So you say, but QM is in a mess today....do you really think that in the end, if we ever do get a real glimpse into the microscopic that it will bear much resemblance to what we think today? If you really believe that, then you haven't looked at the long history of science...rarely does furthered knowledge actually support what we thought we knew.

 

[SSDD]

Planck curves are simply histograms of the type of energy being radiated from an object. The range is dependent on the temperature. Two objects that vary by only 100C will have nearly identical ranges. At any one instant of time the cooler one may emit a higher energy photon than the warmer one, giving a transient period where the energy flow is against the temp gradient. Because the warmer object on average emits higher energy photons, and more of them, this scenario is rare but not impossible. Over any time frames larger than nanoseconds the law of large numbers enforces the SLoD. Statistics rule the macroscopic world.

Again...talking as if you were stating fact. That is one of your more boorish traits Ian...when you go into one of your predictable spiels about what photons are doing and what this or that is doing, would it be so much trouble to qualify the statement with "science thinks" this or that is what is happening rather than speaking as if you were repeating observed, measured fact?

Even if in the end we find that as you say, that every once in a long while, the cooler object may emit a higher energy photon (although how that happens one must wonder) than the warmer object and that one photon every once in a long while may be absorbed by the warmer object, it still doesn't support the AGW hypothesis...Are you claiming that a single photon every once in a long while can actually cause warming? Even if what you say is true, CO2 would still be irrelevant...

 

[SSDD]

"Statistics rule the macroscopic world"... sounds vaguely familiar.

You think statistics rule the microscopic world...that is what the mathematical models based on what we think say...but what is actually going on there is unknown. Claiming that we know is just dishonest.

By the way...statistics is a means to attempt to explain what is going on in the microscopic world...not the actual physical mechanism...

 

[IanC]

The change from classical physics to QM added a new layer of complexity, it did not radically change the macroscopic details of low speed non instantaneous conditions. There may well be another layer that replaces QM but it will give results that approximate QM very closely.

So you say, but QM is in a mess today....do you really think that in the end, if we ever do get a real glimpse into the microscopic that it will bear much resemblance to what we think today? If you really believe that, then you haven't looked at the long history of science...rarely does furthered knowledge actually support what we thought we knew.

Actually QM has a rather amazing history of explaining paradoxes, and making predictions that turned out to be correct. Van der Wahl's or Casimir?

Planck curves are simply histograms of the type of energy being radiated from an object. The range is dependent on the temperature. Two objects that vary by only 100C will have nearly identical ranges. At any one instant of time the cooler one may emit a higher energy photon than the warmer one, giving a transient period where the energy flow is against the temp gradient. Because the warmer object on average emits higher energy photons, and more of them, this scenario is rare but not impossible. Over any time frames larger than nanoseconds the law of large numbers enforces the SLoD. Statistics rule the macroscopic world.

Again...talking as if you were stating fact. That is one of your more boorish traits Ian...when you go into one of your predictable spiels about what photons are doing and what this or that is doing, would it be so much trouble to qualify the statement with "science thinks" this or that is what is happening rather than speaking as if you were repeating observed, measured fact?

Even if in the end we find that as you say, that every once in a long while, the cooler object may emit a higher energy photon (although how that happens one must wonder) than the warmer object and that one photon every once in a long while may be absorbed by the warmer object, it still doesn't support the AGW hypothesis...Are you claiming that a single photon every once in a long while can actually cause warming? Even if what you say is true, CO2 would still be irrelevant...

yes, it would be too much trouble.

I bring this stuff up to counter your bizarre interpretation of the SLoT.

I am saying that all objects radiate according to their temps, all the time, not just when you say they can. there is no Maxwell's Daemon keeping track of a clockwork universe. until you can find some mechanism that turns radiation on and off, I will go with the accepted and logical idea that everything radiates all the time. photons are not like matter, they do not cancel each other out and they can occupy the same space without transfering energy.

 

[SSDD]

Actually QM has a rather amazing history of explaining paradoxes, and making predictions that turned out to be correct. Van der Wahl's or Casimir?

All sorts of completely wrong hypotheses have made accurate predictions...Hell, look at AGW...it made accurate predictions till it didn't.

, it would be too much trouble.

Figures...says a lot when it is to much trouble to qualify what you are saying with the truth.

bring this stuff up to counter your bizarre interpretation of the SLoT.

I don't have any interpretation. I would never try to interpret... The second law says that energy won't spontaneously move from a cool object to a warm object. I can no more explain how or why than you can explain the mechanism of gravity. The law says that energy moves in a certain direction...every observation ever made confirms it...what is there for me to interpret. You are the one saying that it isn't true....you are the one trying to find some way around the law...you are the one looking for some words to convince me, or whoever that the second law doesn't really mean what it says. You want to convince me, show me an observed measured example of energy moving from a cool object to a warm object.

I am saying that all objects radiate according to their temps, all the time, not just when you say they can. there is no Maxwell's Daemon keeping track of a clockwork universe. until you can find some mechanism that turns radiation on and off, I will go with the accepted and logical idea that everything radiates all the time. photons are not like matter, they do not cancel each other out and they can occupy the same space without transfering energy.

I never said that they couldn't... When you start making up arguments for your opposition, you know that you have lost. I have said that energy doesn't radiate from cool to warm...that's what the second law says. How or why it happens no one knows....every observation however, bears out the statement. You believe what you want, but when you start claiming that your beliefs are facts then you cross the line and become a religious zealot.

 

[Crick]

SSDD, we CAN explain how all matter radiates energy based solely on its temperature. What can NOT be explained is how your idea of restricted radiation takes place.

 

[IanC]

Actually QM has a rather amazing history of explaining paradoxes, and making predictions that turned out to be correct. Van der Wahl's or Casimir?

All sorts of completely wrong hypotheses have made accurate predictions...Hell, look at AGW...it made accurate predictions till it didn't.

, it would be too much trouble.

Figures...says a lot when it is to much trouble to qualify what you are saying with the truth.

bring this stuff up to counter your bizarre interpretation of the SLoT.

I don't have any interpretation. I would never try to interpret... The second law says that energy won't spontaneously move from a cool object to a warm object. I can no more explain how or why than you can explain the mechanism of gravity. The law says that energy moves in a certain direction...every observation ever made confirms it...what is there for me to interpret. You are the one saying that it isn't true....you are the one trying to find some way around the law...you are the one looking for some words to convince me, or whoever that the second law doesn't really mean what it says. You want to convince me, show me an observed measured example of energy moving from a cool object to a warm object.

I am saying that all objects radiate according to their temps, all the time, not just when you say they can. there is no Maxwell's Daemon keeping track of a clockwork universe. until you can find some mechanism that turns radiation on and off, I will go with the accepted and logical idea that everything radiates all the time. photons are not like matter, they do not cancel each other out and they can occupy the same space without transfering energy.

I never said that they couldn't... When you start making up arguments for your opposition, you know that you have lost. I have said that energy doesn't radiate from cool to warm...that's what the second law says. How or why it happens no one knows....every observation however, bears out the statement. You believe what you want, but when you start claiming that your beliefs are facts then you cross the line and become a religious zealot.

of course you are interpreting, poorly I might add.

your vision of the SLoT is the equivalent of saying that every year a casino makes money from its gaming tables therefore no one can ever win even a single bet. you are absurd.

you scoff at QM and even the reality of photons but I bet you have no problems believing the results of the MRI done on your tweeked knee. you are absurd.

you give wildly inappropriate examples, like air leaking out of a tire or a rock falling down (ignoring the earth falling up?), when you are discussing energy exchange by photon (radiation). you are absurd.

you bring 'appeal to authority' to new heights. the statements laid down over a hundred years ago describing thermodynamics are so perfect that they even describe the microscopic world which the scientists knew next to nothing about then. you are absurd.



I feel a little bit sorry for you. it is a pity that you seem incapable of synthesizing a logical worldview out of admittedly incomplete evidence but you would rather grab one statement to use as a lifeboat in a sea of uncertainty, keeping your eyes tightly closed. if you opened your eyes you might find that you are floating in a lagoon just steps away from land.

 

[SSDD]

your vision of the SLoT is the equivalent of saying that every year a casino makes money from its gaming tables therefore no one can ever win even a single bet. you are absurd.

I don't have a version of the second law...any claim that I do exhibits a level of dishonesty on par with crick.

you scoff at QM and even the reality of photons but I bet you have no problems believing the results of the MRI done on your tweeked knee. you are absurd.

QM is in its infancy and is rife with contradictions...and photons??..have you seen one?...has anyone seen one?...photons are a construct that attempt to describe a process we don't yet understand...nothing more. The fact that you believe them to be real and just like you describe is moderately laughable. I used to work with a guy back in the early days of computers...guy was crazy smart with regard to computers...talked about computer processes as if they were a community in the computer and he knew everyone....of course it was all bullshit, but he believed it....and it worked for him even though it was bullshit.

give wildly inappropriate examples, like air leaking out of a tire or a rock falling down (ignoring the earth falling up?), when you are discussing energy exchange by photon (radiation). you are absurd.

All observations of energy moving towards the direction of more entropy are wildly inappropriate?...interesting. Got any evidence that the earth is falling anywhere?

bring 'appeal to authority' to new heights. the statements laid down over a hundred years ago describing thermodynamics are so perfect that they even describe the microscopic world which the scientists knew next to nothing about then. you are absurd.

So ONCE AGAIN...lets see the observed, measured example of energy spontaneously moving from a cool object to a warm object....lets see the actual measured example that proves that that quaint old statement is out of date and due to be rewritten....lets see the hard evidence, not a mathematical model proving that the minds that laid down the second law were wrong.

Or not.

I feel a little bit sorry for you. it is a pity that you seem incapable of synthesizing a logical worldview out of admittedly incomplete evidence but you would rather grab one statement to use as a lifeboat in a sea of uncertainty, keeping your eyes tightly closed. if you opened your eyes you might find that you are floating in a lagoon just steps away from land.

Misplaced pity is symptomatic among zealots...You believe that you know the truth and those who don't beleve what you believe must be wrong...Verbally expressing that misplaced pity in lieu of simply providing the hard evidence to support your beliefs is also symptomatic among religious zealots. If you have hard evidence, that proves that the second law is incorrect and should be rewritten to include two way energy flow between objects of different temperatures, then lets see it..otherwise, you are just stating your belief based on your acceptance of someone else's belief.

And don't pretend that QM is settled and there is no hot dispute over the topic between physicists because that would just be a lie...you have chosen your side based on what you believe, not on a complete knowledge of the topic and undeniable physical evidence.[/QUOTE]