Heh. In response to a ridiculous claim making the rounds (I get comment bombed at WUWT daily with that nonsense) which I debunked here: A misinterpreted claim about a NASA press release, CO2, solar flares, and the thermosphere is making the rounds
Dr. Roy Spencer employs some power visual satire, that has truth in it. He writes:
How Can Home Insulation Keep Your House Warmer, When It Cools Your House?!
<sarc> There is an obvious conspiracy from the HVAC and home repair industry, who for years have been telling us to add more insulation to our homes to keep them warmer in winter.
But we all know, from basic thermodynamics, that since insulation conducts heat from the warm interior to the cold outside, it actually COOLS the house.
Go read his entire essay here. <Sarc> on, Roy!
UPDATE: Even Monckton thinks these ideas promoted by slayers/principia/O’Sullivan are ridiculous:
Reply to John O’Sullivan:
One John O’Sullivan has written me a confused and scientifically illiterate “open letter” in which he describes me as a “greenhouse gas promoter”. I do not promote greenhouse gases.
He says I have “carefully styled [my]self ‘science adviser’ to Margaret Thatcher. Others, not I, have used that term. For four years I advised the Prime Minister on various policy matters, including science.
He says I was wrong to say in 1986 that added CO2 in the air would cause some warming. Since 1986 there has been some warming. Some of it may have been caused by CO2.
He says a paper by me admits the “tell-tale greenhouse-effect ‘hot spot’ in the atmosphere isn’t there”. The “hot spot”, which I named, ought to be there whatever the cause of the warming. The IPCC was wrong to assert that it would only arise from greenhouse warming. Its absence indicates either that there has been no warming (confirming the past two decades’ temperature records) or that tropical surface temperatures are inadequately measured.
He misrepresents Professor Richard Lindzen and Dr. Roy Spencer by a series of crude over-simplifications. If he has concerns about their results, he should address his concerns to them, not to me.
He invites me to “throw out” my “shredded blanket effect” of greenhouse gases that “traps” heat. It is Al Gore, not I, who talks of a “blanket” that “traps” heat. Interaction of greenhouse gases with photons at certain absorption wavelengths induces a quantum resonance in the gas molecules, emitting heat directly. It is more like turning on a tiny radiator than trapping heat with a blanket. Therefore, he is wrong to describe CO2 as a “coolant” with respect to global temperature.
He invites me to explain why Al Gore faked a televised experiment. That is a question for Mr. Gore.
He says I am wrong to assert that blackbodies have albedo. Here, he confuses two distinct methods of radiative transfer at a surface: absorption/emission (in which the Earth is a near-blackbody, displacing incoming radiance to the near-infrared in accordance with Wien’s law), and reflection (by which clouds and ice reflect the Sun’s radiance without displacing its incoming wavelengths).
He implicitly attributes Margaret Thatcher’s 1988 speech to the Royal Society about global warming to me. I had ceased to work with her in 1986.
He says that if I checked my history I should discover that it was not until 1981 that scientists were seriously considering CO2’s impact on climate. However, Joseph Fourier had posited the greenhouse effect some 200 years previously; Tyndale had measured the greenhouse effect of various gases at the Royal Institution in London in 1859; Arrhenius had predicted in 1896 that a doubling of CO2 concentration would cause 4-8 K warming, and had revised this estimate to 1.6 K in 1906; Callender had sounded a strong note of alarm in 1938; and numerous scientists, including Manabe&Wetherald (1976) had attempted to determine climate sensitivity before Hansen’s 1981 paper.
He says, with characteristic snide offensiveness, that I “crassly” attribute the “heat-trapping properties of latent heat to a trace gas that is a perfect energy emitter”. On the contrary: in its absorption bands, CO2 absorbs the energy of a photon and emits heat by quantum resonance.
He says the American Meteorological Society found in 1951 that all the long-wave radiation that might otherwise have been absorbed by CO2 was “already absorbed by water vapor”. It is now known that, though that is largely true for the lower troposphere, it is often false for the upper.
The series of elementary errors he here perpetrates, delivered with an unbecoming, cranky arrogance, indicates the need for considerable elementary education on his part. I refer him to Dr. Spencer’s excellent plain-English account of how we know there is a greenhouse effect.
The Viscount Monckton of Brenchley (April 18, 2013)
Myrrh, I’m often mystified by your thoughts. Can I ask a simple, direct question?
If you created a huge, hundred meter diameter focusing lens with a topside coating that reflected all light bandwidths except green (say 500-550nm which pass through unimpeded) and focused all the green light of direct sunlight onto a spot 1-foot-wide and put your hand at that focus, what would happen to your hand? This would be an interesting experiment–I’d be very happy to let you go first.
Gary Hladik and tjfolkerts,
You are both so fundamentally wrong on this issue and at the same time so utterly (and proudly) incapable of seeing it that it’s quite pointless to continue this ‘discussion’. So I won’t. I will only leave you with this:
Repeating the definition of ‘heat’ from Borgnakke & Sonntag (‘Fundamentals of Thermodynamics’ 2009) provided earlier on this thread:
“Heat is defined as the form of energy that is transferred across the boundary of a system at a given temperature to another system (or the surroundings) at a lower temperature by virtue of the temperature difference between the two systems. That is, heat is transferred from the system at the higher temperature to the system at the lower temperature, and the heat transfer occurs solely because of the temperature difference between the two systems. (…) Heat, like work, is a form of energy transfer to or from a system.“
Interesting, don’t you think? HEAT can only be transferred across the boundary of a system. It is never contained WITHIN a system.
So why are you so bent on treating the sphere and the shell as ONE thermodynamic system? When they very obviously are not. If there is a heat transfer occurring between the sphere and the shell, then by thermodynamic definition, the two constitute separate systems.
The first law of thermodynamics only applies to single (isolated) systems. So why on earth are you still insisting on the clearly flawed assumption (and frankly, flawed on an embarrassingly basic level) that one system (the shell) MUST lose as much heat to space as a different system (the sphere) gains from its heat source in order for there to be radiative balance?
No such precondition exists!
http://en.wikipedia.org/wiki/Thermodynamic_system
Of a system and its surroundings: “The system is the part of the universe being studied, while the surroundings is the remainder of the universe that lies outside the boundaries of the system. It is also known as the environment, and the reservoir. Depending on the type of system, it may interact with the system by exchanging mass, energy (including heat and work), momentum, electric charge, or other conserved properties. The environment is ignored in analysis of the system, except in regards to these interactions.”
So, for the surface of the sphere, our first system, the surroundings (its reservoirs) are made up of everything that’s outside or beneath it, in other words: Everything that’s NOT the surface of the sphere.
It’s hot reservoir lies beneath (within). It is the internal heat source, its provider of heat, supplying the surface with a constant flux of 400 W/m^2.
It’s cold reservoir lies outside of it. It is made up of 1) the vacuum between it and the shell, 2) the shell, and 3) space outside the shell.
The surface of the sphere sheds a constant (outgoing) flux of 400 W/m^2 into the vacuum between it and the shell, to balance the incoming flux from the hot reservoir (Qh). This flux is J or Q (Qc).
The surface of the sphere however also gets a flux in return from its surroundings, the inward J1 from the shell. So the final expression for the heat balance between the sphere surface system and its reservoirs (surroundings) is:
J –> || J –> <– J1 || J1 –> or Qh(sphere) = Qc(sphere) = Q’ + Q” = J = (J – J1) + J1 = (400 – 200) + 200 = 400 W/m^2
There is no requirement anywhere for Q” to equal Qc(sphere) at steady state. Q” is merely part of Qc(sphere). Q” is Qc for the shell, not for the sphere.
So, what about the shell, our second system? Its surroundings are made up of … everything outside and inside of it, everything that’s not the shell.
The shell’s hot reservoir is the surface of the central sphere (ultimately, the sphere’s internal heat source).
The flux received from the sphere by the shell is 400 W/m^2. However, at steady state, the shell radiates back 200 W/m^2, so the net transfer of energy (the ‘heat’ transfer) to the shell from the sphere is (400-200=) 200 W/m^2. This is the equilibrated heat gain flux of the shell.
The cold reservoir of the shell is space outside of it. It receives a flux from the outer surface of the shell of 200 W/m^2, balancing exactly the incoming heat flux to the inner surface. The heat balance expression for the shell becomes:
(J – J1 =) J1 –> || J1 –> or Qh(shell) = Qc(shell) = Q’ = Q” = J1 = (400 – 200) = 200 W/m^2
dbstealey says, April 27, 2013 at 6:04 pm:
“Pay no attention to joelshore. He is just miserable because the planet is falsifying his religious belief system.”
Heh. Yes, I’m not sure if he’s only comical or if we should somehow feel sorry for him … 😉
joeldshore says, April 27, 2013 at 6:22 pm:
“Kristian,
Just for the sake of curiosity, is it your belief that what you are arguing for in this thread is in agreement with what is said in widely-used and respected introductory physics textbooks (…)”
Yup. Of course. Not ‘belief’ though …
joeldshore says, April 27, 2013 at 6:46 pm:
“This is kind of fascinating from a PER (Physics Education Research) point of view. PER has found that students, even once they have learned Newton’s Laws, still tend to fall back on an Aristotlean viewpoint, which includes notions that a force must be supplied to keep an object moving.
Our friend Kristian has come up with an analogous view with energy: Energy must in net be supplied just to keep an object at a certain temperature. And, energy can just sort of get used up and disappear…It doesn’t have to be conserved.”
Riiight …
Can anyone here provide me with a single physics textbook example (or better yet, an actual account of a controlled experiment conducted in a vacuum chamber) where it is shown, or even remotely discussed, that supplied with a constant energy input, the central sphere will heat up beyond the original input energy temperature with the shell in place around it? A single one where this is even considered as a topic. Shouldn’t this phenomenon after all be a highly interesting subject to delve into, especially seen from an engineer’s point of view, giving us a tool to create incredibly high temperatures from a small original input simply by applying layers/shells of radiative insulation like that around the source. If this phenomenon is so natural and real and important, why won’t any physics or engineering textbooks let their students learn anything about it? Why are all such examples (and by that, I mean ALL) only concerned with the equilibrated temperature of the shell and the reduction of heat loss to space? Why is this adding back of energy to create even higher source temperatures only a topic in the realm of the radiative GHE?
“How many perfectly absorptive shells, separated by vacuums, must we put around a sphere (or a satellite) in space with a constant input of say 400 W/m^2 for it to reach a steady state surface temperature of say 10,000 Kelvin? And how many fewer such shells do we need if their reflectivity is say 0,9?”
Why can’t we find any such questions or problems being posed in any physics or engineering textbooks …?
Kristian says:
Okay, then let me ask you a few questions:
(1) Why do you think that both Robert Brown (rgbatduke) and I, two people who teach physics at the university level and who have very different views on whether AGW is a big concern, both say that you are wrong (along with a lot of other people here, of course)?
(2) Why do you think that the algebra-based physics textbook that we use here at RIT (and is used at many schools around the country) http://www.amazon.com/College-Physics-Strategic-Technology-MasteringPhysics/dp/0321815114/ have a whole page discussing the greenhouse effect and global warming in which they say, among other things: “Because it’s easier for visible radiant energy to get in than for infrared to get out, the earth is warmer than it would be without the atmosphere. The additional warming of the earth’s surface because of the atmosphere is called the greenhouse effect…Carbon dioxide is a powerful absorber of infrared radiation. Adding more carbon dioxide makes it even harder for emitted thermal radiation to escape, increasing the average temperature of the earth. The net result is global warming…Global warming is one of the most serious challenges facing scientists, engineers, and all citizens in the 21st century”?
(3) Just in case you think it is a fluke, why do you think that the calculus-based physics textbook that we use here at RIT (and is used at many schools around the country) http://www.amazon.com/University-Physics-Modern-MasteringPhysics-Package/dp/0321675460 have a discussion of the greenhouse effect and global warming in which they say among other things: “Molecules of CO2 in our atmosphere have the property that they absorb some of the infrared radiation coming upward from the surface. They then re-radiate some of the absorbed energy but some of the re-radiated energy is directed back down toward the surface instead of escaping into space. In order to maintain thermal equilibrium, the earth’s surface must compensate for this by increasing its temperature T and hence its total rate of radiating energy (which is proportional to T^4).”? It then goes on to discuss the increase in CO2 so far and the projected increase and resulting warming expected and the consequences of this, concluding with the statement, “Coping with these threats is one of the greatest challenges facing 21st-century civilization.”
Kristian …
Yes, that is obvious.
We aren’t. And we never have.
We are simply assuming conservation of energy for the shell. The only loss of energy for the shell is radiation to space. The only gain of energy for the shell is thermal IR from the sphere. Since the energy of the shell is staying the same (ie the temperature is staying the same), then the loss must equal the gain. (This, of course, is after the system has come to its steady-state conditions.)
Let’s be more careful with definitions, because frankly I am having a hard time following your nomenclature. Let’s use “Q” for “heat flux” = “net rate that thermal energy is being transferred across each square meter of a boundary”. Fortunately in our case, there are no non-thermal energy exchanges (eg no work, no chemicals moved …). Let’s use “J” for the flux of photons, which can go both ways. (This seems to be pretty close to the way you are using the letters, and pretty close to the way they are used in many other places.)
FOR THE SPHERE
Qh(sphere) enters the sphere from below. Qc(sphere) leaves from above. I believe this would be
Qh(sphere) –> || Qc(sphere) –>
in your nomenclature, where clearly Qh(sphere) = Qc(sphere) , by conservation of energy for a steady-state situation.
At the outer surface of the planet, Qc(sphere) consists only photons. In your notation, we could summarize the situation at the outer surface of the planet as
| J –> <– J1
We have an outward flux of “J” and an inward flux of “J1”, which gives a net flux of J-J1. From this we can immediately deduce Qc(sphere) = J-J1.
So we have found your error:
Qh(sphere) = Qc(sphere) = J [Kristian]
Qh(sphere) = Qc(sphere) = J-J1 [Correct]
FOR THE SHELL
(J – J1 =) J1 –> || J1 –> or Qh(shell) = Qc(shell)
This I agree with. (J-J1) enters the shell from below and J1 leaves from above. (J-J1) = J1, or J1 = ½ J. (Assuming the shell is “close” to the sphere).
Put it all together and we have
Qh(sphere) = Qc(sphere) = J-J1 = ½ J = J1 = Qh(shell) = Qc(shell)
The net flow is 400 W/m^2 enters the sphere and 400 W/m^2 leaves the sphere and 400 W/m^2 enters the shell and 400 W/m^2 leaves the shell. (When said that way it almost seems too obvious.) Between the sphere and shell, the flow is J = 800 W/m^2 of photons up and J1 = 400 W/m^2 of photons down = 400 W/m^2 net.
Conservation of energy and simple algebra once again lead us to the correct answer. Physics works. 🙂
DANG! Missed a formatting tag above. About 8 lines down that should be …
Conservation of energy applies everywhere at all times. The First Law is conservation of energy applied to thermodynamics. But for this problem, it is useful to apply the First Law to the sphere and the shell separately.
We are simply assuming conservation of energy for the shell. …
Kristian
Have you read the recent post on pyrgeometers on tallblokes?
It verifies earlier points we both made there.
Its rather uncomfortable reading for backradiation warmers.
http://tallbloke.wordpress.com/2013/04/26/pyrgeometers-untangled/
Kristian says:
I’ll do you one better and give you two very popular introductory physics textbooks (the ones we use at RIT) that talk about the greenhouse effect and global warming in particular:
Knight, Jones, and Field, “College Physics: A Strategic Approach”, 2nd edition has a whole page discussing the greenhouse effect and global warming in which they say, among other things: “Because it’s easier for visible radiant energy to get in than for infrared to get out, the earth is warmer than it would be without the atmosphere. The additional warming of the earth’s surface because of the atmosphere is called the greenhouse effect…Carbon dioxide is a powerful absorber of infrared radiation. Adding more carbon dioxide makes it even harder for emitted thermal radiation to escape, increasing the average temperature of the earth. The net result is global warming…Global warming is one of the most serious challenges facing scientists, engineers, and all citizens in the 21st century.”
Young and Freedman, University Physics, 13th edition has a discussion of the greenhouse effect and global warming in which they say among other things: “Molecules of CO2 in our atmosphere have the property that they absorb some of the infrared radiation coming upward from the surface. They then re-radiate some of the absorbed energy but some of the re-radiated energy is directed back down toward the surface instead of escaping into space. In order to maintain thermal equilibrium, the earth’s surface must compensate for this by increasing its temperature T and hence its total rate of radiating energy (which is proportional to T^4).”? It then goes on to discuss the increase in CO2 so far and the projected increase and resulting warming expected and the consequences of this, concluding with the statement, “Coping with these threats is one of the greatest challenges facing 21st-century civilization.”
Why do you think that both Robert Brown (rgbatduke), myself, and TJ Folkerts, three people who teach physics at the university level and who have a range of views on whether AGW is a big concern, all say that you are wrong (along with a lot of other people here, of course)?
RACookPE1978 says:
April 27, 2013 at 2:44 am
From above:
“So sunlight is 1360 watts per square meter at top of atmosphere and by time reaches earth surface it’s around 1000 watts per square meter- losing about 360 watts per square meter.
For simplicity, let’s assume those values are correct.”
Now. If every second of every day, 360 of Trenberth’s 1360 watts DON’T penetrate a supposedly “completely transparent” atmosphere, but since their energy does arrive at top-of-atmosphere but doesn’t arrive at bottom-of-atmosphere, then how do those 360 watts get “lost” from the earth’s overall system?
The problem is with this incorrect assertion, the 1360 watts/m^2 which arrives at the top of the atmosphere is only capable of arriving at the bottom of the “completely transparent” atmosphere at a very limited location for a very limited time. This can only occur at the equator and only at the local noon, every where else and at all other times it will be less than that because of the difference in the angle of incidence at the location. So that 1360 will actually be:
1360*cos(dlat)* cos(dlon) which when integrated over the whole illuminated hemisphere accounts for the division by 4.
Clearly, they ARE absorbed by the oxygen, nitrogen and argon and dust and aerosols, and ARE re-radiated by those same gasses and dusts and solids. However, just as clearly, they ARE also ignored by the CAGW community because their theory does not allow such inconsistent, inconvenient maths.
They are not absorbed by oxygen, nitrogen and argon, except by oxygen above the troposphere in the UV, absorption by water in the near IR occurs in the troposphere, as well as elastic scattering by particulates and aerosols. Contrary to your assertion, that loss is taken into account, it’s in the Trenberth diagram for instance. 77/342 is scattered some of which is from clouds and 67/342 is absorption, which amounts to 225/1360 and 196/1360 which more than covers your 360/1360. Absorption by the water in the troposphere isn’t lost to the system since in the most part is transferred to the atmosphere as heat. Absorption by ozone and oxygen in the stratosphere doesn’t make it to the troposphere and will be lost via radiation as will elastic scattering.
tjfolkerts says, April 28, 2013 at 7:42 am:
“So we have found your error:
Qh(sphere) = Qc(sphere) = J [Kristian]
Qh(sphere) = Qc(sphere) = J-J1 [Correct]”
Tim, this is not treating the sphere and the shell as two separate systems. This is treating them as one. The error is yours and yours alone. You’re ignoring the outward J1 from the shell, the other part of J. As I showed you in the very post you’re flailingly trying to refute.
You’re wrong and you know it.
Regarding that, did you read my post right above yours?
Care to answer?
And why not calculate the effect of multiple shells/layers on the sphere surface temperature while you’re at it?
Satellites often have MLIs with 20 highly reflective, vacuum separated insulating layers covering the craft. According to your logic with the back-adding of energy and the need for the heat loss from the outermost layer to space to exactly match the original input to the instruments inside, ideally, if you let the energy input run constantly (let’s say 400 W/m^2 from within to the surface of the instruments), then 4-5 such layers only would be enough to melt the device long before equilibration. With 20 such layers, the steady input to maintain the interior instrument temperature of 290K (400 W/m^2) would only need to be 3,8 x 10^-24 W/m^2! Fantastic, isn’t it?! Why do we never hear of such amazing real-world facts? And of how to utilize them?
joeldshore says, April 28, 2013 at 9:41 am
That’s very much NOT what I was asking for. Read my post (all of it) again, then you might find out.
What you’re giving me here is just the same tired old arguments from assertion and assumption from the specific realm of the radiative GHE. No real-world back-up whatsoever. And theoretically, exceedingly sloppy. I sure hope you’re not teaching thermodynamics.
“Why do you think that both Robert Brown (rgbatduke), myself, and TJ Folkerts, three people who teach physics at the university level and who have a range of views on whether AGW is a big concern, all say that you are wrong (along with a lot of other people here, of course)?”
I would prefer it if you just provided me with what I’m asking for in the post you’re quoting rather than this huffing and puffing with arguments from authority.
Kristian: Let me remind you how this transpired.
I said:
You replied:
Now that I have provided conclusive evidence that your “not ‘belief'” was completely wrong, you’ve decided these are “the same tired old arguments from assertion” or “arguments from authority”.
So, basically, you won’t accept our attempts to explain to you the basic concept of conservation of energy and you won’t accept authorities on the subject even though you claimed to be quite sure that the authorities would agree with you. Clearly, you just want to wallow in your own ignorance. Have fun!
Bryan says, April 28, 2013 at 9:40 am:
“Kristian
Have you read the recent post on pyrgeometers on tallblokes?
It verifies earlier points we both made there.
Its rather uncomfortable reading for backradiation warmers.
http://tallbloke.wordpress.com/2013/04/26/pyrgeometers-untangled/“
Yes, I have. Funny how these old ‘truths’ that have been allowed to proliferate without questioning just proves plain wrong and silly as soon as someone simply care to try and find out what actual science they rest upon.
Problem is, most of the time, the proponents need to find out for themselves. They can’t simply be told. As we both know …
Myrrh says:
April 28, 2013 at 3:15 am
Myrrh,
Only one question: as no visible light reaches the ocean depths below a few hundred meters, what happens with the energy contained in that light between zero and 200 meter depth were it all is absorbed by water and/or suspended matter?
Kristian says: “I would prefer it if you just provided me with what I’m asking …”
The problem, Kristian, is that even when I *do* provide exactly what you are asking for and walk you through the steps, you invent objections like “you are treating it as one system” even though I was following exactly your arguments (often evening using your notation).
Point to ONE SPECIFIC equation that you object to in my post. Explain why you think it is wrong.
Kristian
Joel Shore says
“Young and Freedman, University Physics, 13th edition has a discussion of the greenhouse effect and global warming in which they say among other things: “Molecules of CO2 in our atmosphere have the property that they absorb some of the infrared radiation coming upward from the surface.”
Interestingly Joel and i had an exchange about this about two years ago at WUWT.
I have the 9th edition of the same book (1996).
No mention of the Greenhouse Effect.
Apparently this theory is very new or has been included to sell books to Climate ‘Science’ students.
During the posts then several people (from all sides) pointed out that the textbook had made several mistakes in the Greenhouse entries
It was a real ‘cut and paste job’ which ruined an otherwise good textbook..
It is surely shameful that a good textbook is ruined by including passages of second rate pseudoscience to suit the AGW faith inquisition
Ferdinand Engelbeen says:
“I do disagree with Joel Shore on the real effect of a CO2 doubling, but that doesn’t mean that I should disagree with him on every other item. In fact, the skeptic community is its own enemy and lacks credibility due to attacking those items where the science is rock solid: that CO2 levels increased due to human emissions and that an increase of CO2 in the atmosphere induces some increase in temperature, all other things being equal.”
Ferdinand, I agree completely with what you wrote here.
• CO2 causes some warming. We do not know how much, but it is too small to be measured independent of natural warming
• The excess CO2 in the atmosphere is the result of fossil fuel burning
• About 4 ppm per year is added to the atmosphere, and 2 ppm is retained; the rest is absorbed by the biosphere
• Excess CO2 is also emitted due to natural global warming. There is plenty of empirical evidence proving that fact
Regarding Joel Shore, his physics is fine — as far as it goes. But obviously there is something missing, something he is not aware of, because after a ≈40% rise in CO2, global temperatures have stopped rising for the past decade and a half. The universal prediction was that rising CO2 would cause global warming. In the ’90’s there were endless predictions stating that rising CO2 would trigger runaway global warming. Skeptics were scoffed at.
But those predictions were completely wrong. All of them. Therefore, something major is missing from the analysis. I think there is a different effect between radiative physics in a closed laboratory container, and radiative physics in a convecting atmosphere. There are also negative feedbacks, both known and unknown. Clouds are not properly accounted for, etc.
When a conjecture such as rising CO2 = runaway global warming is found to be totally wrong, per empirical observations over many years, honest scientists will admit they got it wrong and try to figure out why. But many mainstream climate scientists still try to defend their failed predictions instead of working with skeptical scientists to find out where they went wrong.
Finally, there is no scientific evidence demonstrating that rising CO2 is harmful, but there is a lot of real world evidence showing that the added CO2 is beneficial. But when the government hands out more than $100 BILLION in federal grants since 2001, plenty of scientists get the message: demonize “carbon”! Because no one will get much of that money if they tell the truth: that at current and projected concentrations, CO2 is globally harmless, and it is beneficial to the biosphere. More is very likely better.
I am always ready to change my mind. But if I do, it will be based on empirical measurements, not on the current narrative. It is a real shame that alarmist scientists like Michael Mann and lots of others refuse to acknowledge that rising CO2 has not had the predicted effect, and therefore their conjecture has been falsified.
Kristian says: “Satellites often have MLIs with 20 highly reflective, vacuum separated insulating layers covering the craft.”
And why do they do that? Exactly for the reason we are talking about! The heat loss is decreased dramatically!
“With 20 such layers, the steady input to maintain the interior instrument temperature of 290K (400 W/m^2) would only need to be 3,8 x 10^-24 W/m^2!”
Wherever you got “3,8 x 10^-24 W/m^2”, it is not even close to right. For blackbody shells
1 layer = 1/2 as much heat loss
2 layers = 1/3 as much heat loss (not 1/4)
3 layers = 1/4 as much heat loss (not 1/8)
…
20 layers = 1/21 as much heat (not 1/ 2^21) So 20 blackbody shells would result in about 5% as much heat loss.
Of course, no one would use black body surface for such a thing, since reflective coatings are MUCH more efficient. 20 layers of highly reflecting shells (emissivity = 0.01) would lower the heat output by a factor of ~ 0.00025, or ~ 0.1 W/m^2. That is certainly quite an improvement (about 100x better than the black body shells) , but now where near the 0.00000000000000000000000001 times better that you claim.
(Real efficiency would be a little less, but still quite impressive for such thin, light-weight insulation.)
Details at http://en.wikipedia.org/wiki/Multi-layer_insulation
Kristian says:
April 28, 2013 at 5:28 am
The surface of the sphere however also gets a flux in return from its surroundings, the inward J1 from the shell. So the final expression for the heat balance between the sphere surface system and its reservoirs (surroundings) is:
J –> || J –> or Qh(sphere) = Qc(sphere) = Q’ + Q” = J = (J – J1) + J1 = (400 – 200) + 200 = 400 W/m^2
Kristian,
I am just trying to follow your reasoning, but I think something goes wrong in the first part of the equation where you insist that the outgoing radiation of the sphere = J.
The incoming energy for the sphere is J + J1. The outgoing energy is J (=Qc, or call it Jsphere). Thus the sphere is not in energy balance. That means that the sphere must heat up. With as result an increase of the outgoing radiation from the sphere to the shell, until Jsphere (Qc) = J + J1. But that also increases J1, as the shell receives more energy from Jsphere, thus the shell heats up too. At the moment that J1 = 400 W/m^2 (and thus Jsphere = 800 W/m^2), every part of the system (sphere, shell) and the whole system (from heat source within the sphere to space) is in steady state equilibrium.
Kristian says:
Not sure how you got your result…But, you just motivated me to work out the formula one finds using the correct laws of radiative physics and conservation of energy for N opaque shells having a reflectance R and an absorbance [and emittance] (1-R) surrounding a perfect blackbody emitter (and neglecting issues of differences in radii, i.e., assuming the radii of the shells are essentially the same as the radius of the object at the center) . [Yes…I guess I really don’t have anything better to do this afternoon!]
The result is that the temperature T_0 of the blackbody object at the center and the temperature T_N of the outer shell are related by
T_0^4 = [2*N/(1-R) – (N-1)] * (T_N)^4.
Hence, the input sigma*T_N^4 necessary to maintain a temperature of T_0 = 290 K for N = 20 would be ~19 W/m^2 for 20 blackbody (R = 0) shells and ~0.512 W/m^2 for 20 shells with a very good reflectance R = 0.95. Even if you had 20 shells with a really fantastic reflectance of R = 0.99, the necessary input would still be ~0.100 W/m^2.
So, your calculation is not even close to correct.
tjfolkert says:
Damn…I just worked my butt off to calculate this and I could have looked up the answer on Wikipedia!?! Well, at least I am glad to see that they got the same answer as I did.
Bryan says:
It was just added in the 13th edition.
It is not that theory is very new but that it sometimes takes physics textbooks a while to get around to including practical physics applications from other fields.
You have the perfect unfalsifiable religion: If a respected physics authority disagrees with your notions of physics, clearly that authority has been corrupted and can no longer be trusted! Have fun believing your garbage-science.
Ferdinand Engelbeen says:
April 28, 2013 at 1:43 pm
Kristian,
The html language deleted part of the equation that I copied from your message, but I suppose that you already knew that…