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.
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Gas molecules don’t travel in straight lines very far. They collide. Energy in these molecules is spread in a distribution described by temperature, across various degrees of freedom (1/2 kT).
Thermal conduction in the Earth seems to be very slow. There are temperature gradients below ground. Caves near the surface seem to have a temperature roughly equal to the average yearly temperature. Temperatures under ground increase with greater depth. Could the heat of radioactive decay make much difference at the surface? Perhaps it’s the old chicken and egg dilemma.
It seems a significant contribution to the Earth having an elevated temperature compared to a black body is the delay in reradiating absorbed light from the sun. The surface warms and some of that energy works its way deep into the ground, or into water below the surface. There is heat capacity, heat conduction, and fluid mixing in the oceans all moving absorbed energy to and from the surface where it might be radiated back to space. The Earth is a heat sink with poor thermal conduction characteristics. If the Earth absorbs light more efficiently than it radiates, then the surface temperature must rise before equilibrium is reached. That higher temperature is thermal energy that can be transported deeper into the Earth. It will take time to penetrate, and it will take time to rise back up to the surface after the sun sets.
If some of the daily energy is retained and not radiated at night, then the Earth’s temperature rises. A glacier has similar properties. Eventually all of the snow that falls on a mountain melts, but if some of the snow never melts during the summer, a glacier will form. The length depends on various parameters like snowfall, but eventually all of the snow melts. The glacier length stabilizes when the rate of snowfall balances the rate of melting. If some of the heat absorbed during the day is not reradiated, then the surface the next day will start out warmer. The average surface temperature will rise until the total amount of energy radiated over 24 hours equals the total amount absorbed during the day.
The atmosphere can pick up thermal energy by conduction and move it to cooler places. The atmosphere also has its own heat capacity. However, there is no way in hell that our atmosphere retained excess heat due to some hypothetical compression event over 4 billion years ago.
If you reduce the number of molecules to a fairly small number, you can see that Willis’s argument, beguiling as it is, is wrong. Consider a single-molecule system, for example. Does anyone doubt that the molecule’s translational kinetic energy is greater when it is lower in the gravitational field than when it is higher? Does that reverse relationship disappear when a second molecule is added?
As the number of molecules gets large, the system approaches isothermic. But a (very small) lapse rate persists.
DAMMIT, WILLIS:
PLEASE ADDRESS THE EMPIRICAL EVIDENCE, WHICH WILL ULTIMATELY RESOLVE THIS ARGUMENT! WHY DO YOU REFUSE TO DO THIS?
[Moderator’s suggestion: If you didn’t YELL at him maybe more would be accomplished? Maybe? -REP]
Willis, do you have a rebuttal or reply to my post http://wattsupwiththat.com/2012/01/19/perpetuum-mobile/#comment-870067?
I think that you had it right to begin with – the molecules move faster down low. That means temperature is higher down low. The fact that energy density is constant is a red herring.
I am a semanticist at heart. I read with interest these posts and wonder about two little words: “at equilibrium”. I suspect these theories are thinking about something that doesn’t actually exist in the “Real World”, like so many thought experiments I see from so many very learned and intelligent people.This begs me to ask several questions:
1) Is the atmosphere of the Earth “at equilibrium”?
2)If the atmosphere of the Earth is not “at equilibrium”, does this discussion have any meaning, other than as a diverting thought experiment?
3)If the atmosphere of the Earth is not “at equilibrium”, how will it behave?
Like much climatic, I suspect we are undone by our “Human” view of things.
IMHO,
When, Dr. Robert Brown speaks, people should shut up and listen.
A gentle reminder of the core issue raised by Willis: It seems to me that many posts are injecting unwanted complexities. While it is true that the Earth includes a large body of water, rotates in a 24 hour period, has a core that produces a (small) amount of energy, and so on and so forth, the question to be resolved is the behaviour of a column of “air” – actually any gas – in a gravity field, particularly its change in temperature (if any) with altitude.
To resolve this requires the question to be formulated as simply as possible. So to understand how gravity affects temperature distribution we ignore – for the time being – anything extraneous. No sun, no rotation of the Earth, no surface or sub-surface effects. Simply a column of gas in a gravity field. Nothing more.
I appreciate the effort many have put into their posts, and many are very interesting. But first let us understand how this works in the simplest manner possible.
David says:
January 19, 2012 at 5:21 pm
“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.”
I agree with this. Respectfully, Willis is wrong.
Gravity fields are not acceleration fields. In uniform acceleration fields the temperatures are indeed uniform. For a column of material In a gravity field to be of uniform temperature the column would need to be walled radially from the gravity point source.
Dear Mr Willis Eschenbach;
As you have [SNIP: Markus, sorry, but this sort of stuff contributes nothing to the discussion. You can make this sort of comment AFTER a cogent debunking. Please. -REP]
If we had a single pane of glass and the temperature outside was 10 degrees and it was 20 degrees inside, then the temperature within the pane would vary linearly from 10 to 20 degrees across the width of the pane. Right? Now let us pretend we had a 10 kilometre long solid copper tube in the form of a vertical pole that was totally insulated except that the bottom 10 metres was in asphalt at 30 degrees C and the top 10 metres and was exposed to air at -50 degrees C. Then you would automatically have a temperature gradient of 8 degrees C per kilometre. How is this fundamentally different from what really happens with air? If the sun heats the surface and outer space is cold, you automatically get a temperature gradient without resorting to work done by increasing pressures.
I take your kilometer’s tall cylinder of atmosphere in thermal equilibrium and flip it over, like flipping an hour glass. It involved no input of work as its height did not change, so the column’s energy remains constant. But now the gas at temp T that was at the top has been wildly compressed, making it much, much hotter, while the gas at temp T that was at the bottom has been expanded, making it much, much colder. If you let it get anywhere close to thermal equilibrium I’m going to flip it over again, and since I’m not putting in any work, I can do this all day, continuously forcing your air column back to the dry adiabatic lapse rate as I sip a margarita.
I love doing jobs that don’t involve an input of work and constantly overturn an idealized thermal equilibrium, because it’s just that easy.
Willis, thanks, that is a beautiful picture of a perpetual motion machine.
When I was a lad with a crude workshop I did play for a while with the PM notion. My version was powering an air turbine with the exhaust from a compressed gas source. Of course the the turbine was going to compress even MORE gas and the turbine would produce lots of free energy.
Then I went to engineering school…..
One thing I learned in school was that if something works there will be tens or hundreds of people using it. For example the IC engine, the airplane, the integrated circuit, and (not for much longer sadly, see the recent news about Kodak) photographic emulsions on flexible roll film.
So I ask myself, if the Greenhouse Gas Effect is REAL (still in question it seems after these many decades) WHY is it that NOBODY has figured out how to apply it to any practical problem and solve, or at least ameliorate said problem ?????
Think about it for a second, there are lots of very obscure physical effects that have practical applications. For example, the Bernoulli effect is what makes a plane fly (although there is still some debate; does the effect “suck” the plane upwards, or does it “push” the plane upwards, this one seems like tomato .vs. thamato to me). The Peltier effect has been used for decades to cool electronic devices and has lately been applied to drink coolers.
It sure seems that once a physical effect is observed and characterized some sharp engineers find a way to apply it to solve a problem.
So why is it that after decades no sharp engineer has figured out how to apply the Greenhouse Effect to solve any problem, like maybe using the effect to create “net energy gains” in the insulation surrounding a building, that would sure reduce energy usage ???
I see a few possibilities;
1) Engineers are dumber than climate scientists, seems unlikely, some are probably dumber, but I bet at least a few are smarter.
2) There are a dearth of practical problems to be solved, seems unlikely, there always seems to be lots of problems to be solved, like how do we feed everybody and keep them warm. Or how do we allow folks to have fun on a floating cruise ship without letting an incompetent skipper rip a hole in the side by driving it over rocks and “catching” one in the hull, OK we have some more work to do there….
3) Maybe the Greenhouse Effect does not exist, or it exists, but does not provide any “net energy gains” or produce a “higher equilibrium temperature” as claimed ?
Personally, I’m betting on choice #3 and giving odds of several Million to One.
I have not yet evaluated any of the “gravity caused” theories others have suggested and you are discussing, and they may in fact have some merit. But I am convinced that the ”Greenhouse Effect” hypothesis is a modern version of the Perpetual Motion Machine. BTW you are not supposed to be granted a patent on PM machines, and I see nobody trying to patent the “Greenhouse Effect” or applications of if, surely somebody would have tried to lock up all the potential business opportunities if the “effect” really existed as promised ???
Cheers, Kevin.
Somewhat off topic, has anyone built up an error budget for the AGW hypothesis? Not just how skill(less) the models are, but from a mearsurement perspective.
Our understanding of the historic record has error bars that dwarf the analysis. Our recent data has significant error. The spatial error is enormous.
What is all of this hysteria actually saying? We think a 2° rise is too fast, but the historic record can’t be resolved to that fine a point; and that 2° rise is based on models that don’t replicate the record fed with data widely dispersed, inconsistent measurements of fluctuating weather.
Gravity has NO AFFECT ON TEMPERATURE.
How many times must it be said.
You people are reading science fiction.
You have to do WORK to create a change in temperature – this is basic thermodynamics!!!!
If an object falls in a gravitational field then potential energy will be converted to kinetic energy which will create heat. However a stable column of air in equilibrium does not create any energy or heat.
This is so so so basic that I am afraid I may have to give up this website altogether in disgust.
Imagine you have a tube of air 1km long. Now instead of being a tube, you basically turn it onto a cone. Lets say the bottom of the tube represents 1/10,000 of the surface of the Earth, and the top represents 1/10,000 of the “surface” of an imaginary sphere at 1km altitude. This is why I said I would model the atmosphere as a series of concentric spheres representing conditions at the altitude of each sphere. Now, temperature and heat. At molecule at the ground might be 100F and a molecule at 40km might be 100F but there are far fewer of them at 40km. So if you stick your thermometer out the window of the bazillionth floor at 40km altitude, far fewer molecules will strike your thermometer and transfer heat to it. So your thermometer will cool until it reaches an equilibrium where the heat it is radiating is equal to the heat it is receiving. So the temperature of the molecules can be the same (100F) but there is less heat per given amount of space because there are fewer molecules.
Equilibrium of the atmosphere doesn’t exist. As can be seen in this thread, just trying to understand the climate in even the simplest terms is a daunting task.
Topologists long ago proved that the wind will always blow somewhere…
right after they mistook their donuts for their coffee cups.
@ur momisugly David says:
January 19, 2012 at 7:20 pm
From what I’m understanding, I agree.
However, I can’t help but wondering what would happen, keeping the extraneous items out as you said – “no sun, no rotation of the Earth, no surface or sub-surface effects. Simply a column of gas in a gravity field. Nothing more” out, except in a situation where the gravity isn’t constant. Wouldn’t, in that case, we have a continuously moving gas due to the changing gravity? Would we then see heat, energy, or work being “created” by the fluctuating gravity?
Just wondering.
Willis,
You keep asking for an elevator speach supporting the N&Z analysis.
Here is my attempt.
(1) any worthwhile theory should describe reality or it is worthless and should be discarded.
(2) When you make due allowance for differences in their distances from the sun, the temperature of Mercury, relative to Venus, is too low to be explained by the greenhouse theory.
(3) However this is very closely explained by their different atmospheric pressures at the surface.
(4) That is also true for other bodies in the solar system.
(5) That in turn suggests that the various laws on physics mentioned in this thread, while themselves highly likely to be true, do not interact in the manner that has been outlined by people critical of the two unpublished N&Z (20110, 2012) papers.
I really do not think that this arguement will be settled using theoretical “thought” experiments. These remind me in so many ways of the best work of the IPCC.
We need a theory to explain why the surface temperature of the various solar bodies can be derived as a function of distance from the sun (solar radiance) plus near surface atmospheric pressure.
N&Z have provided their theory.
The task of critics is now to come up with better, more economical (Occham’s Razor) theories.
As Lucy Skywalker has said – this is a game changer.
the game HAS changed.
We must now all respond to the new paradigm.
Jeremy says:
January 19, 2012 at 7:52 pm
///////////////////
Jeremy
Just three quick questions.
1. How much work is involved in the creation of the diurnal/atmospheric bulge?
2. How much work is involved in the moving of the tides?
3. Are not the same processes that are involved in moving the tides also at work on the atmosphere but not so readily apparent to an Earth boud observer since he cannot see the ebb and flow of the atmosphere as it is sublected to the gravitaional forces of the celestrial bodies?
The gravitational forces being exerted on the atmosphere are not constant. The atmosphere is never in equalibrium.
Perhaps you will answer my questions before departing this web site.
In the absence of an external energy source the column would indeed become isothermal.
Temperature at both top and bottom would be the same despite the higher energy content per unit volume at the bottom.
Mass is simply a form of energy so a denser mass per unit volume contains more energy but it does not follow that it has a higher temperature than a less dense unit of volumre.
Temperature is simply a measure of kinetic or vibrational energy and molecules can have the same averaged kinetic energy in both a dense and a less dense unit of volume.
Gravity just primes the system by placing greater density of molecules at the bottom of the column. It does not provide any heat or kinetic energy in itself.
If an external energy source is then switched on then the kinetic response to that energy input is density dependent and so the temperature gradient with density then appears.
More molecules per unit volume will convert a larger proportion of the incoming radiative energy into kinetic form and it is kinetic energy that is refected in a higher temperature.
Furthermore higher density involves more collisional activity due to closer packing of the molecules so that kinetic energy stays in kinetic form for longer whilst it is bounced to and fro between molecules before eventually being released in the form of outgoing longwave.
The more incoming radiation that is converted to kinetic energy per unit volume AND the longer it stays in kinetic form the higher the temperature will become.
The adiabatic temperature gradient is therefore a consequence of gravity induced pressure PLUS uneven energy distribution (more molecules per unit volume) PLUS incoming radiation.
ALL the components must be in place at the same time to produce the temperature gradient.
THEN the entire structure of the planetary atmosphere is effectively forced to adjust itself to provide the most efficient mix of energy transfer mechanisms both radiative and non radiative so as to maintain that adiabatic temperature gradient.
Radiative processes only perform a mopping up function. In so far as non radiative processes fail to return the system to that adiabatic lapse rate then radiative processes step in to make up the difference.
The S – B equations do not deal with the non radiative processes.
The final oucome in terms of atmospheric structure can become highly complex and that is where composition becomes relevant and why no planet with an atmosphere matches the S – B equations.
Imagine a glass tube 100 miles tall reaching from the surface of the earth to outer space. Insert the base of the tube in concrete and then fill it with Coca-Cola or some other carbonated beverage. Now add peanuts at the top and watch what happens. At first the peanuts sink but as the fall, they gather bubbles which slows their descent until …..
LOL.
Sorry. But Jeremy is right. This discussion is almost totally nuts.
KevinK says:
January 19, 2012 at 7:42 pm
////////////////////
Kevin
I have made this point to Willis on a number of occassions and it has always been met with deadly silence.
Why are we seeking to exploit solar energy by way of PV cells when this has obvious drawbacks such as sunlight is not received at night or when cloudy. Trenberth suggests that on average solar power is just 184 w per sq m. Why are we not exploiting backradiation or at any rate researching its use when it is claimed to be in the order of 333 w per sq m come rain or shine 24/7? If this was truly a souce of energy capable of doing sensible work, we would be exploiting it since it would cure over night the world’s energy needs. Something is amiss here and it is probably that physists employed by energy companies or at the cutting edge of research do not consider it a source of sensible work.