Guest Post by Willis Eschenbach
Since at least the days of Da Vinci, people have been fascinated by perpetual motion machines. One such “perpetuum mobile” designed around the time of the civil war is shown below. It wasn’t until the development of the science of thermodynamics that it could be proven that all such mechanisms are impossible. For such machines to work, they’d have to create energy, and energy cannot be either created or destroyed, only transformed.
I bring this up for a curious reason. I was reading the Jelbring hypothesis this afternoon, which claims that greenhouse gases (GHGs) are not the cause of the warming of the earth above the theoretical temperature it would have without an atmosphere. Jelbring’s hypothesis is one of several “gravito-thermal” theories which say the heating of the planet comes from gravity rather than (or in some theories in addition to) the greenhouse effect. His thought experiment is a planet with an atmosphere. The planet is isolated from the universe by an impervious thermally insulating shell that completely surrounds it, and which prevents any energy exchange with the universe outside. Inside the shell, Jelbring says that gravity makes the upper atmosphere colder and the lower atmosphere warmer. Back around 2004, I had a long discussion on the “climateskeptics” mailing list with Hans Jelbring. I said then that his theory was nothing but a perpetual motion machine, but at the time I didn’t understand why his theory was wrong. Now I do.
Dr. Robert Brown has an fascinating post on WUWT called “Earth’s baseline black-body model – a damn hard problem“. On that thread, I had said that I thought that if there was air in a tall container in a gravity field, the temperature of the air would be highest at the bottom, and lowest at the top. I said that I thought it would follow the “dry adiabatic lapse rate”, the rate at which the temperature of dry air drops with altitude in the earth’s atmosphere.
Dr. Brown said no. He said that at equilibrium, a tall container of air in a gravity field would be the same temperature everywhere—in other words, isothermal.
I couldn’t understand why. I asked Dr. Brown the following question:
Thanks, Robert, With great trepidation, I must disagree with you.
Consider a gas in a kilometre-tall sealed container. You say it will have no lapse rate, so suppose (per your assumption) that it starts out at an even temperature top to bottom.
Now, consider a collision between two of the gas molecules that knocks one molecule straight upwards, and the other straight downwards. The molecule going downwards will accelerate due to gravity, while the one going upwards will slow due to gravity. So the upper one will have less kinetic energy, and the lower one will have more kinetic energy.
After a million such collisions, are you really claiming that the average kinetic energy of the molecules at the top and the bottom of the tall container are going to be the same?
I say no. I say after a million collisions the molecules will sort themselves so that the TOTAL energy at the top and bottom of the container will be the same. In other words, it is the action of gravity on the molecules themselves that creates the lapse rate.
Dr. Brown gave an answer that I couldn’t wrap my head around, and he recommended that I study the excellent paper of Caballero for further insight. Caballero discusses the question in Section 2.17. Thanks to Dr. Browns answer plus Caballero, I finally got the answer to my question. I wrote to Dr. Brown on his thread as follows:
Dr. Brown, thank you so much. After following your suggestion and after much beating of my head against Caballero, I finally got it.
At equilibrium, as you stated, the temperature is indeed uniform. I was totally wrong to state it followed the dry adiabatic lapse rate.
I had asked the following question:
Now, consider a collision between two of the gas molecules that knocks one molecule straight upwards, and the other straight downwards. The molecule going downwards will accelerate due to gravity, while the one going upwards will slow due to gravity. So the upper one will have less kinetic energy, and the lower one will have more kinetic energy.
After a million such collisions, are you really claiming that the average kinetic energy of the molecules at the top and the bottom of the tall container are going to be the same?
What I failed to consider is that there are fewer molecules at altitude because the pressure is lower. When the temperature is uniform from top to bottom, the individual molecules at the top have more total energy (KE + PE) than those at the bottom. I said that led to an uneven distribution in the total energy.
But by exactly the same measure, there are fewer molecules at the top than at the bottom. As a result, the isothermal situation does in fact have the energy evenly distributed. More total energy per molecules times fewer molecules at the top exactly equals less energy per molecule times more molecules at the bottom. Very neat.
Finally, before I posted my reply, Dr. Brown had answered a second time and I hadn’t seen it. His answer follows a very different (and interesting) logical argument to arrive at the same answer. He said in part:
Imagine a plane surface in the gas. In a thin slice of the gas right above the surface, the molecules have some temperature. Right below it, they have some other temperature. Let’s imagine the gas to be monoatomic (no loss of generality) and ideal (ditto). In each layer, the gravitational potential energy is constant. Bear in mind that only changes in potential energy are associated with changes in kinetic energy (work energy theorem), and that temperature only describes the average internal kinetic energy in the gas.
Here’s the tricky part. In equilibrium, the density of the upper and lower layers, while not equal, cannot vary. Right? Which means that however many molecules move from the lower slice to the upper slice, exactly the same number of molecules must move from the upper slice to the lower slice. They have to have exactly the same velocity distribution moving in either direction. If the molecules below had a higher temperature, they’d have a different MB [Maxwell-Boltzmann] distribution, with more molecules moving faster. Some of those faster moving molecules would have the right trajectory to rise to the interface (slowing, sure) and carry energy from the lower slice to the upper. The upper slice (lower temperature) has fewer molecules moving faster — the entire MB distribution is shifted to the left a bit. There are therefore fewer molecules that move the other way at the speeds that the molecules from the lower slice deliver (allowing for gravity). This increases the number of fast moving molecules in the upper slice and decreases it in the lower slice until the MB distributions are the same in the two slices and one accomplishes detailed balance across the interface. On average, just as many molecules move up, with exactly the same velocity/kinetic energy profile, as move down, with zero energy transport, zero mass transport, and zero alteration of the MB profiles above and below, only when the two slices have the same temperature. Otherwise heat will flow from the hotter (right-shifted MB distribution) to the colder (left-shifted MB distribution) slice until the temperatures are equal.
It’s an interesting argument. Here’s my elevator speech version.
• Suppose we have an isolated container of air which is warmer at the bottom and cooler at the top. Any random movement of air from above to below a horizontal slice through the container must be matched by an equal amount going the other way.
• On average, that exchange equalizes temperature, moving slightly warmer air up and slightly cooler air down.
• Eventually this gradual exchange must lead to an isothermal condition.
I encourage people to read the rest of his comment.
Now, I see where I went wrong. Following the logic of my question to Dr. Brown, I incorrectly thought the final equilibrium arrangement would be where the average energy per molecule was evenly spread out from top to bottom, with the molecules having the same average total energy everywhere. This leads to warmer temperature at the bottom and colder temperature at elevation. Instead, at thermal equilibrium, the average energy per volume is the same from top to bottom, with every cubic metre having the same total energy. To do that, the gas needs to be isothermal, with the same temperature in every part.
Yesterday, I read the Jelbring hypothesis again. As I was reading it, I wondered by what logic Jelbring had come to the conclusion that the atmosphere would not be isothermal. I noticed the following sentence in Section 2.2 C (emphasis mine):
The energy content in the model atmosphere is fixed and constant since no energy can enter or leave the closed space. Nature will redistribute the contained atmospheric energy (using both convective and radiative processes) until each molecule, in an average sense, will have the same total energy. In this situation the atmosphere has reached energetic equilibrium.
He goes on to describe the atmosphere in that situation as taking up the dry adiabatic lapse rate temperature profile, warm on the bottom, cold on top. I had to laugh. Jelbring made the exact same dang mistake I made. He thinks total energy evenly distributed per molecule is the final state of energetic equilibrium, whereas the equilibrium state is when the energy is evenly distributed per volume and not per molecule. This is the isothermal state. In Jelbrings thought experiment, contrary to what he claims, the entire atmosphere of the planet would end up at the same temperature.
In any case, there’s another way to show that the Jelbring hypothesis violates conservation of energy. Again it is a proof by contradiction, and it is the same argument that I presented to Jelbring years ago. At that time, I couldn’t say why his “gravito-thermal” hypothesis didn’t work … but I knew that it couldn’t work. Now, I can see why, for the reasons adduced above. In addition, in his thread Dr. Brown independently used the same argument in his discussion of the Jelbring hypothesis. The proof by contradiction goes like this:
Suppose Jelbring is right, and the temperature in the atmosphere inside the shell is warmer at the bottom and cooler at the top. Then the people living in the stygian darkness inside that impervious shell could use that temperature difference to drive a heat engine. Power from the heat engine could light up the dark, and provide electricity for cities and farms. The good news for perpetual motion fans is that as fast as the operation of the heat engine would warm the upper atmosphere and cool the lower atmosphere, gravity would re-arrange the molecules once again so the prior temperature profile would be restored, warm on the bottom and cold on the top, and the machine would produce light for the good citizens of Stygia … forever.
As this is a clear violation of conservation of energy, the proof by contradiction that the Jelbring hypothesis violates the conservation of energy is complete.
Let me close by giving my elevator speech about the Jelbring hypothesis. Hans vigorously argues that no such speech is possible, saying
There certainly are no “Elevator version” of my paper which is based on first principal physics. It means that what I have written is either true or false. There is nothing inbetween.
Another “gravito-thermal” theorist, Ned Nikolov, says the same thing:
About the ‘elevator speech’ – that was given in our first paper! However, you apparently did not get it. So, it will take far more explanation to convey the basic idea, which we will try to do in Part 2 of our reply.
I don’t have an elevator speech for the Nikolov & Zeller theory (here, rebuttal here) yet, because I can’t understand it. My elevator speech for the Jelbring hypothesis, however, goes like this:
• If left undisturbed in a gravity field, a tall container of air will stratify vertically, with the coolest air at the top and the warmest air at the bottom.
• This also is happening with the Earth’s atmosphere.
• Since the top of the atmosphere cannot be below a certain temperature, and the lower atmosphere must be a certain amount warmer than the upper, this warms the lower atmosphere and thus the planetary surface to a much higher temperature than it would be in the absence of the atmosphere.
• This is the cause of what we erroneously refer to as the “greenhouse effect”
Now, was that so hard? It may not be the best, I’m happy to have someone improve on it, but it covers all the main points. The claim that “gravito-thermal” theories are too complex for a simple “elevator speech” explanation doesn’t hold water.
But you can see why such an elevator speech is like garlic to a vampire, it is anathema to the “gravito-thermal” theorists—it makes spotting their mistakes far too easy.
w.
Willis Eschenbach says:
January 20, 2012 at 11:56 pm
Joe Born says:
January 20, 2012 at 12:35 pm
… I have to confess that two weeks ago I was arguing over at tallbloke’s place for the same position you’re taking now: http://tallbloke.wordpress.com/2012/01/01/hans-jelbring-the-greenhouse-effect-as-a-function-of-atmospheric-mass/#comment-12926. Currently I think I was wrong then and that you’re wrong now. Maybe by tomorrow you and Dr. Brown will have convinced me otherwise.
Joe, all considerations about the mechanism go nowhere. Consider the outcome. If it’s true that gravity can separate molecules by temperature, then we can pull energy out of tall insulated cylinders of air, Jelbring is right and we never have to worry about energy again.
Do you believe that we can do that? Really?
Willis, the rules for falsifying a proposition by appeal to the consequent theoretical constructability of a perpetual motion machine of the second kind are very clear. You have to specify the machine and demonstrate that it will produce work.
Armwaving is insufficient.
I made this point a lot earlier in this thread and you ignored it. Just as I pointed out to Robert brown why his appeal to “the zero’th law failed and he ignored that too.
Unresponsiveness speaks volumes.
A Physicist:
Multi layer insulation – Never knew that!
http://www.technifab.com/cryogenic-resource-library/cryogenic-insulation.html
==
RADIATION FROM THE SKY
From the excellent source of info:
Pat Arnott – thank you!
http://www.patarnott.com/atms749/pdf/LongWaveIrradianceMeas.pdf
Atmospheric longwave irradiance uncertainty: Pyrgeometers compared to an absolute sky-scanning radiometer, atmospheric emitted radiance interferometer, and radiative transfer model calculations Rolf Philipona, etal.
Please check out fig 3:
Figure 3. Longwave downward irradiance measured with all
pyrgeometers and the absolute sky-scanning radiometer from
September 22 to 29, 1999, at SGP. Field calibration and Albrecht
et al. formula with C, k2, and K is used for all pyrgeometers.
Nighttime and daytime slots are used for the analysis
of nighttime and daytime measurements.
If I read this correctly there is not much difference in LW IR between day and night.
Around 20 to 50%
Now note that this is LW IR so most of the solar sw input is not present. and solar IR is small
We know(?) that N2 and O2 and Argon do not emit much (zero mainly) IR..
But obviously the sw solar hits the ground gets re-emitted as cool LW ir. this gets reflected (re-emitted actually) back down by IR (or magic depending on your point of view). So this would explain the daytime level. Some of the GHGs will transfer warmth to the non ghgs by collision some will be radiated upwards.
At night there is NO source of solar input, and only a warm atmosphere. So where is the night time IR coming from? The system measures radiation not temperature, The non GHGs cannot emit radiation. So we are left with magic or GHGs.
Now combine this info with the down and up spectra shown in slide 9 of:
http://www.patarnott.com/atms749/powerpoint/ch6_GP.ppt
Where the GHG emissions are obvious.
they are reduced in TOA flux and increased in down welling flux.
Someone said but why is it miss from TOA if it goes down it must also go out. But of course some gets absorbed by the sea/land and provides heat which will be spread thinly over the BB radiation spectrum.
Can anyone explain these OBSERVED an recorde effects without GHGs?
The air moving up and down exchanges potential energy (PE) for kinetic energy (KE). The air moving down loses PE but gains KE, and vice versa for the air moving up. A higher KE means a higher temperature, a lower KE means a lower temperature. So the air moving down increases in temperature (KE), while the air moving up decreases in temperature (KE). This will maintain the adiabatic lapse rate, warmer air at the bottom of the column and cooler air at the top.
Your second point is wrong, there is no equalisation of temperature. Therefore, your conclusion in the third point of your elevator speech is also wrong.
Ah, so the air is moving, is it? What part of equilibrium is escaping you?
Now try again where the air is not moving in bulk because there is no differential heating or cooling of the air, which is trapped in an adiabatic container with no heat flow in or out. It quickly — for all practical purposes instantaneously — develops a pressure gradient and (in response to its bulk compressibility) density gradient, so that there is no bulk transport up or down the air column. At that point, heat moves from higher temperature to lower temperature within the gas because that is what heat does. In order for heat not to flow, the gas would have to not conduct, not thermally mix, not be a physical gas at all.
As you note, the temperature of the gas is directly proportional to its kinetic energy, but molecules of gas are not on average moving up and down the gas column so there is no net conversion of kinetic energy to potential or vice versa. They are however, colliding and exchanging kinetic energy. Those collisions, on average, share the kinetic energy equally among all of the molecules. Any time a molecule has more than the average, it is likely to (on average) lose it in collisions to others, any time one has less it is likely to gain it.
What maintains the adiabatic lapse rate is convection caused by differential heating of the gas column, specifically more heat being delivered to the bottom. Why is it so very difficult for you to see how having a spontaneous separation of temperature in a gas column due to gravity enables a perpetual motion machine of the second kind to be built, and thus is absolutely impossible?
rgb
DavidB says:
January 21, 2012 at 7:34 am
Tallbloke:
Your last argument in response to my ‘tennis ball’ model seems to prove too much. Using this argument you could prove that heat can never be conducted along a metal rod. Suppose one end of the rod is in a fire, and the other end in a bowl of ice water. There is a continuous gradient of temperature along the rod. But if we conceptualise the rod as a collection of infinitely thin ‘slices’, each slice will be at the same temperature as the next one. Therefore, by your argument, ‘no heat will flow’. And yet it does!
Hi David. My argument was assuming an energy equilibrium with a consequent thermal gradient as in Jelbring’s hypothesis. Clearly, if you start stacking extra energy in at one end, heat will flow. This doesn’t affect my argument.
Cheers
Rog
If we wanted gravity derived concepts for heat, we should look at the temperature profiles of planets like Jupiter to see if there is a corresponding gravity induced effect. A quick look at the temperature profile here:
Not the best choice of examples. Jupiter is radiating more heat than it receives because it is still slowly collapsing at the center. What you want is a planet that is in (near) thermal equilibrium, with an atmosphere too thick for the center to be differentially heated by sunlight. The other problem is that the figure you post only goes to the base of the troposphere. The troposphere is by definition the part of the atmosphere that is differentially warmed at the bottom and cooled at the top and exhibits (approximately) an adiabatic lapse rate maintained by vertical convection.
The interesting question is — what is the thermal profile inside the troposphere? The atmospheres of the gas giants do not stop at the bottom of the troposphere. It is difficult to maintain convection (of any depth) while heating from the top. It is not at all unreasonable that the interior atmosphere of the gas giants resembles nothing more than the oceans of the Earth, with a more or less constant temperature and very little convection.
Nobody argues that the troposphere isn’t warmer at the bottom and cooler at the top. That’s what a troposphere is — the part of the atmosphere that is warmer at the bottom and cooler at the top. If you look at the very same figures for Jupiter (and for that matter Uranus or other planets) you can also see the layering and composition of the greenhouse gases in those atmospheres that seem to establish the thermal gradient that drives the convection that establishes the adiabatic lapse rate that perpetuates the greenhouse effect and makes the troposphere’s thermal distribution dynamically stable.
rgb
Robert Brown says:
January 21, 2012 at 7:24 am
Here’s a shorter elevator speech:
If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part. If there is net heat flow within the system, it is not in equilibrium.
Wow, so perfectly correct! Two laws of thermodynamics (0 and 2). Done.
I’ll add it to my collection of potentially conflicting formulations of the thermodynamics laws – thanks for endorsing it.
Tallbloke, your statement is wrong-on-the-facts: Willis (and I) did describe a perpetual motion of the second kind, namely a thermopile column, said column having its warm end at ground-level and its cold end at altitude.
And the mistake in “gravito-thermal” theories is evident too: these theories include a thermodynamic potential (namely the temperature) together with a gravitational potential, and yet they (wrongly) neglecting the chemical potential.
Just to mention, ideal gases do have a chemical potential, whose effects must be included in any thermodynamically consistent theory that involves particle exchange (in this case, the exchange of molecules between layers of the atmosphere). Because “gravito-thermal” theories mistakenly omit the ideal gas chemical potential, it is unsurprising that the predictions of “gravito-thermal” theory violate basic thermodynamical principles (precisely as Willis asserted at the beginning of this post).
Hopefully, further study of the theory of chemical potentials will clarify these issues for the authors and fans of “gravito-thermal” theories. Wikipedia’s article on chemical potentials is a good start, and includes many further references.
Joel Shore;
Great…Now all I have to do if I perform a fit of y vs. x with 100 free parameters is break it into two equations>>>
Stop Joel. You are making a fool of yourself. Their final equation is Equation 8 and it has two variables in it. Two. count ’em. Two.
Joel Shore;
The above is the exact argument made by Alan Siddons, one of the “Slaying the Skydragon” crew. It is an extremely silly argument. >>>
Unable to refute it you instead try to equate it to something else. Is it right or isn’t it?
Joel Shore;
The radiative greenhouse effect is the only thing that can explain how the surface of the Earth can be at an average temperature so high that it emits ~390 W/m^2 while the Earth as seen from space only emits ~240 W/m^2 and is thus still in radiative balance with what it receives from the sun.>>>
Really Joel? Really? You cling to math so ridiculously wrong that your attempt to justify it is just pathetic. You have no idea what the theoretical black body temperature of the earth is, you have no idea what the practical black body temperature of the earth is, and thus you have no idea what the difference between the two is, let alone what causes it. But do read BenAW’s comment upthread where he has a nice explanation of EXACTLY how it works. You insist on not only ignoring the falacies introduced into your conclusions by the misaplication of SB Law, you insist also on ignoring the heat capacity of the planet, a point that I have made to you many times and which you continue to ignore.
You earned my respect in a variety of threads a while back, you have now lost it entirely and I think it tragic that someone as supposedly intelligent as Willis Eschenbach has somehow been duped by your duplicity.
Robert Brown says:
January 21, 2012 at 7:50 am
Why is it so very difficult for you to see how having a spontaneous separation of temperature in a gas column due to gravity enables a perpetual motion machine of the second kind to be built, and thus is absolutely impossible
As I said to Willis, armwaving is insufficient.
The rules for falsifying a proposition by appeal to the consequent theoretical constructability of a perpetual motion machine of the second kind are very clear. You have to specify the machine and demonstrate that it will produce work continually forever.
I have become convinced that the isothermal hypothesis, although correct as an approximation, is theoretically true only in the limit….
(referring to the following from tallbloke):
It is from the thus-obtained Velasco et al. Equations 5 and 6 that they claim to obtain their Equation 8 for temperature as a function of altitude, and it is that equation that seems to me not to jibe with any significant lapse rate: although it does have temperature fall with altitude, the drop, if my calculations are correct, is negligible.
Does anyone see where the authors or I went wrong here?
Sure. You and the authors seem to fail to appreciate the fact that any lapse rate in equilibrium violates the second law of thermodynamics.
You obviously understand thermo and some stat mech, so surely you understand Willis (and my own, independent) argument. In your imagined atmosphere, with hotter temperatures anywhere that are maintained by e.g. gravity as a steady state, if you run a thermally insulated conductor from the hot to the cold, what will happen, Joe? How long will it happen?
That’s right, heat will flow (to equalize the temperature difference) because that’s what heat does — it flows from hot to cold through any material that can conduct heat. It doesn’t matter if the gas parcels in thermal contact with the ends of the “heat pipe” are at the top or bottom of a vertical column of air or running between two adiabatically isolated containers of air at different temperatures and pressures, heat will flow from the hot side to the cold side. If Velasco is predicting that the gas will spontaneously separate into hot and cold reservoirs, well, I don’t think it is possible to imagine a more pure example of a violation of the second law, can you?
The beauty of the laws of thermodynamics is that it no longer matters if one can find the precise error made by Velasco in a complicated stat mech analysis. In all probability it involves including momentum or failing to achieve local equilibrium in the first place — ultimately what he is asserting is that there is a failure of detailed balance (because detailed balance leads to isothermal equilibrium). But no matter — heat will not flow forever in an isolated system, will it? And yet, if the top and the bottom of the container maintain themselves at different temperatures, it will, the instant you provide an alternative pathway for heat to flow in the still isolated system.
If Velasco has somehow proven that gravity acts as Maxwell’s Demon — which is precisely what this is — then either he deserves a Nobel Prize, for proving that the second law is openly violated in the Universe and at the same time solving our energy crisis as we can start building 100% efficient perpetual motion machine of the second kind heat engines, engines that just recycle heat into work indefinitely, or he deserves to be instantly ignored until he goes back and finds his own mistake. Personally, I wouldn’t dare to publish a paper that asserted that the second law is violated, that gravity acts like Maxwell’s Demon in any atmosphere ideal or real, because I know that if I somehow got that as a conclusion, my work would almost certainly be incorrect. I’d be just as leery of publishing something with an error in units, or that violated energy conservation.
rgb
Richard M;
This was the same argument Joel tried to use against me back in Ira’s thread. It’s unfortunate that they are willing to discard what may very well be a valid correlation by simply waving their hands.>>>
Frankly I am disgusted. Equation 8 in N&Z’s article has two variables, and anyone who can read can see that. All their results are calculated using THAT equation. Trying to represent it as having four variables by pointing to an intermediate step is an outright lie.
Willis, please. Read the effing Equation 8 for yourself and set the record straight.
Robert Brown says:
January 21, 2012 at 7:24 am
“Here’s a shorter elevator speech:
If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part. If there is net heat flow within the system, it is not in equilibrium.
Wow, so perfectly correct! Two laws of thermodynamics (0 and 2). Done./rgb”
Perfectly wrong since you refuse to include gravity in the system you are treating. Since you now are informed that the Zeroth Law doesn´t work in this situation it seems that you are practising “willful ignorance” which does not belong to scientific methods.
Best
Hans Jelbring
tallbloke says:
January 21, 2012 at 7:10 am
“Assuming your A and B have at least some dimension, then a thermal gradient across them would mean that the top surface of A will be at the same temperature as the bottom surface of B where they contact. Therefore no heat will flow. Even so, the average temperature of the whole of body A will be higher than that of B. QED.”
Tallbloke, please bear in mind that for any parcel that leaves an air layer, another parcel must enter to conserve mass, and the parcel that enters has an equal likelihood of expanding on entry as compressing. Thus on balance the number of parcels that expand when entering the layer must equal the number of parcels that compress when entering, leaving no net change in the energy content of the layer, and no opportunity for perpetual motion on account of the adiabatic process. However, there is still conduction, which will eventually remove any temperature gradient that exists in the absence of an external source of power. It should be clear that an external source of power is required to develop the adiabatic temperature profile and in our neighborhood the sun does the trick.
Can somebody please conceive this fact; Energy cabn be also employed, not just conserved.
Add kinetic energy to matter and the E does not equal mc/2.
OK, once again we have a case of “get an intro physics textbook and read it before stating things that you don’t understand and that are in any event incorrect”.
First of all, energy cannot be “employed”. Free energy can be employed, then it turns into heat. Heat cannot be employed to make work unless there are two thermal reservoirs at different temperatures. If you want to discuss this, please learn the laws of thermodynamics. If you want to assert that the laws of thermodynamics are incorrect, all I can say is don’t be silly! That may not stop you from being silly, but it should.
Second, E = \gamma m c^2 (for an isolated massive particle moving at constant speed in an inertial frame). This includes the kinetic energy. In fact, the low-velocity “usual” form of the KE is the first non-constant term in a binomial/Taylor series expansion of \gamma m c^2. A common way of asserting this is to include the \gamma in the m and say that particles with kinetic energy are more massive. This is, in fact, the case — a hot object is indeed more massive than the same object when cold.
rgb
Extend the column or cylinder to TOA and you have a mechanism to lose the top layer to space fairly rapidly, and by logical extension, the whole atmosphere.. Some disconnect with reality here?
Not at all. Learn about “escape velocity”. This is how the Earth does, gradually, lose atmosphere. It just takes a long, long time for the heavier molecules at the average temperature of the Earth.
rgb
In the event that anyone read my previous post, I should point out the following: Stygia is a perpetual motion machine. It was defined as such by Willis himself. A perfectly insulating, perfectly reflective shell defines a closed, perfectly lossless system: the very definition of a perpetual motion machine.
The average temperature of Stygia must drop as light is generated but there will be a point where the energy reabsorption (and heating) of the planet will exactly balance the energy extracted by the heat engine. Stygia will be light but colder than if it was dark.
In answer to the charge that we could build energy sources that extract energy from a temperature gradient in the atmosphere. The energy drained from the atmosphere is replenished by insolation. Well known parallels would be the photovoltaic cell or wind turbine. Extracting energy directly or indirectly from the energy of insolation. Not very efficient I grant you but that’s why we don’t want to rely on renewables.
BenAW;
What both approaches are neglecting is that the earths surface consist mostly of oceans,
70% area, minimum 3 km deep and a temperature on average of +2C, already 20K higher
than the blackbody temperature the GHE uses when the sun has heated the blackbody.>>>>
I recommend BenAW’s comment upthread to everyone who demands an explanation of surface temperature that is higher than blackbody via a means other that back radiation. The earth surface is ALREADY above the blackbody temp, all the sun has to do is MAINTAIN it, and there is sufficient energy from the sun to do that while also satisfying the laws of thermodynamics. you cannot arrive at that conclusion however unless you first properly apply SB Law instead of starting off with mind bogglingly WRONG averages of a set of variables that CANNOT be compared via averages.
BenAW, the one quibble I have with your comment is that N&Z missed this. My reading of N&Z is that it is founded upon this (amongst several other things).
Robert Brown says:
January 21, 2012 at 7:39 am
The problem is that GHGs and back radiation does not explain the vertical temperature of the atmosphere. The inescapable conclusion of this is that the GHG model is not capable of explaining our atmosphere and that there is more at ‘play’ than the GHG model would suggest.
Why not?
Since there is nothing more unphysical than 390 W/m^2 backradiation. Such an effect can easily be felt by the skin. IR radiation in dífferent directions are no vector quantities that can cancel each other. If you have two suns shining from opposite directions you will fell the heat from both directions. The same is true about any electromagnetic radiation and IR is of that type.
Since you don´t feel any heat fromn any direction during night time it is all bull. I would glacly examine all påredtended measurements if I get information of the instrument and their constructions. This fraud is just passing any limits and is degrading science to superstition.
It is good to know that you and willis are great IPCC supporters.
Robert Brown says:
January 21, 2012 at 8:28 am
This is starting to look like a bit like a battle between 19th century physics and 20th century physics.
The concept of heat doesn’t not rise superior to the concept of atoms. If the movement of atoms under the influence of gravity shows they lose kinetic energy as they rise then some heat disappears and becomes gravitational potential energy. What heat remains still flows, but that heat lost cannot flow.
Bart says:
January 21, 2012 at 2:43 am
Not plausible. The thermal conductivity of air is low. You need a very large temperature gradient to get rapid conductance. That sounds like the same argument that Bill Illis made on the other thread that the short time between molecular collisions could somehow prevent an excited molecule from radiating. But collisional energy transfer must be orders of magnitude faster than radiative transfer for LTE to apply. Emission is determined by the number of molecules or surface states that are excited. That number is a constant in any small volume where LTE applies. For every excited state that is de-excited by collision, another is created by another collision. That’s the how Maxwell-Boltzmann statistics work. LTE only breaks down at very high altitudes in the atmosphere.
You can hand wave all you want about non-equilibrium thermodynamics, but you have yet to demonstrate that they actually apply and give a better fit to observations. The observed emission spectra of surfaces and the atmosphere and spectra calculated assuming that LTE applies are the same within the experimental error of the measured (and calculated ab initio) line parameters and the experimental error of the observing spectrometer.
pochas says:
January 21, 2012 at 8:32 am
Tallbloke, please bear in mind that for any parcel that leaves an air layer, another parcel must enter to conserve mass, and the parcel that enters has an equal likelihood of expanding on entry as compressing. Thus on balance the number of parcels that expand when entering the layer must equal the number of parcels that compress when entering, leaving no net change in the energy content of the layer, and no opportunity for perpetual motion on account of the adiabatic process. However, there is still conduction, which will eventually remove any temperature gradient that exists in the absence of an external source of power.
Hi Pochas, my two line proof which Robert Brown continues to ignore shows that the thermal gradient in a gravitationally forced gas column which is at energy equilibrium will not conduct heat (KE).
As Trick put it:
[Any claim that] the column will be isothermal, meaning all at the same temperature top to bottom…. violates the 2nd law; KE + PE = constant at each h in the presence of an inexplicable gravity field in the gaseous cv of interest, namely an adiabatic (no gain or loss of heat from CV) GHG-free air column.
The proof again incase Robert wants to respond:
tallbloke says:
January 21, 2012 at 7:10 am
“Assuming your A and B have at least some dimension, then a thermal gradient across them would mean that the top surface of A will be at the same temperature as the bottom surface of B where they contact. Therefore no heat will flow. Even so, the average temperature of the whole of body A will be higher than that of B. QED.”
Robert Brown says:
January 21, 2012 at 7:50 am
“What maintains the adiabatic lapse rate is convection caused by differential heating of the gas column, specifically more heat being delivered to the bottom. Why is it so very difficult for you to see how having a spontaneous separation of temperature in a gas column due to gravity enables a perpetual motion machine of the second kind to be built, and thus is absolutely impossible?
What I prove in my E&E paper is that “dynamic” DALR is equal to the “static” DALR so convecting is not needed to reach the maximum entropy situation. All available processes will act to reach taht process. It is the content of the 2:nd law of thermodynamics applied in an insulated atmosphere.
I am interested how you are going to construct your perpetuum mobile out of ideal gases. You or anybody else has alread disingrated and your bound energy belongs to the total inclosed energy from start of the thought experiment.
Joe Born,
Quick and dirty. Meteorologists use a concept called potential temperature to look at atmospheric temperature profiles. It’s the temperature that would result if a packet of air were moved back to the surface adiabatically. Obviously an atmosphere with an adiabatic lapse rate has a potential temperature gradient of zero. Potential temperature is, in fact, a measure of entropy. An adiabatic lapse rate is isentropic. So now lets make the atmosphere isothermal. Potential temperature now increases with altitude so the average potential temperature, and therefore the entropy of the system, has increased. The entropy of the atmosphere could be increased even more by making the temperature increase with altitude. But that’s not stable. Heat would be conducted back to the surface because of the temperature gradient. Therefore, an isothermal atmosphere has the maximum stable entropy.
jelbring:
“If there is a temperature gradient between two parts of a system, net heat flows from the warmer part to the cooler part. If there is net heat flow within the system, it is not in equilibrium.”
this is a definition. it is not wrong. get literate – then you can get logical – then you can get scientific. you aren’t close yet.
Robert Brown says
“What maintains the adiabatic lapse rate is convection caused by differential heating of the gas column, specifically more heat being delivered to the bottom. Why is it so very difficult for you to see how having a spontaneous separation of temperature in a gas column due to gravity enables a perpetual motion machine of the second kind to be built, and thus is absolutely impossible?”
Robert it seems that some within the Climate Science define convection as an UNSTABLE vigorous vertical exchange of air. .
See bottom of page 13.
The stable condition (hydrostatic approximation) is used to derive the DALR. See page 12
Air parcels moving up and down at constant speed (no unbalanced force) will track the DALR.
These air parcels are assumed not to exchange heat with their surroundings.
On going up expansion work PdV is stored by the surroundings(temperature dropping by 9.8K/km)
At TOA there will be a loss of heat by radiation to space causing the down phase
On going down the surroundings do work on the parcel (PdV) (temperature increasing by 9.8K/km)
Stationary parcels will not change temperature.
This atmospheric condition is known as the neutral atmosphere and can be stable particularly at night.
See the near neutral RESIDUAL LAYER page 31
These two idealised adiabatic processes (like the adiabatic stages in the Carnot Cycle) will result in the parcel returning to Earth with nearly the same temperature as leaving (the slight drop being accounted for by radiation at TOA).
Energy supply is from Sun heating the Earth surface and atmosphere during daylight and the Earth surface at night