Guest post by Ira Glickstein
Albert Einstein was a great theoretical physicist, with all the requisite mathematical tools. However, he rejected purely mathematical abstraction and resorted to physical analogy for his most basic insights. For example, he imagined a man in a closed elevator being transported to space far from any external mass and then subjected to accelerating speeds. That man could not tell the difference between gravity on Earth and acceleration in space, thus, concluded Einstein, gravity and acceleration are equivalent, which is the cornerstone of his theory of relativity. Einstein never fully bought into the mainstream interpretation of quantum mechanics that he and others have called quantum weirdness and spooky action at a distance.
So, if some Watts Up With That? readers have trouble accepting the atmospheric “greenhouse” effect because of the lack of a good physical analogy, you are in fine company.
For example, in the discussion following Willis Eschenbach’s excellent People Living in Glass Planets, a commenter “PJP”, challenged the atmospheric “greenhouse” effect:
“The incoming energy (from the sun) you express in w/m^2, lets simplify it even more and say that energy is delivered in truckloads. Lets say we get 2 truckloads per hour. … when we come to your semi-transparent shell [representing greenhouse gases (GHG) in the atmosphere], you are still getting two truckloads per hour, but you say that these two truckloads are delivered to both the earth and to the shell — that makes 4 truckloads/hr. Where did the extra two truckloads come from?”
In that thread, I posted a comment with an analogy of truckloads of orange juice, representing short-wave radiation from Sun to Earth, and truckloads of blueberry juice, representing longwave radiation between Earth and the Atmosphere and back out to Space. A later commenter, “davidmhoffer” said “Ira, That was a brilliant explanation. …”
This Post is a further elaboration of my physical analogy, using a pitching machine and yellow and purple balls in place of the truckfulls of juice.
Graphic 1 shows the initial conditions. The Sun is a ball pitching machine that, when we turn it on, will throw a steady stream of yellow balls towards the tray of a weight scale, which represents the Earth. The reading on the scale is analogized to “temperature” and, with the Sun turned off, reads “0” arbitrary units.
TURN ON THE “SUN”
Graphic 2 shows what happens when the Sun is turned on and there are no GHG in the Atmosphere. The stream of yellow balls impact the tray atop the weight scale and compress the springs within the well-damped scale until equilibrium is reached. The scale reads “1”. This is analogous to the temperature the Earth would reach in the absence of GHG.
The balls bounce off the tray and, for illustrative purposes, turn purple in color. This is my way of showing that Sun radiative energy is mostly in the “shortwave” visible and near-visible region (about 0.3μ to 1μ) and that radiative energy from the warmed Earth is mostly in the “longwave” infrared region (about 6μ to 20μ). The Greek letter “μ” (mu) stands for a unit of length called the “micron” which is a millionth of a meter.
Since, at this stage of my physical analogy, there are no GHG in the Atmosphere, the purple balls go off into Space where they are not heard from again. You can assume the balls simply “bounce” off like reflected light in a mirror, but, in the actual case, the energy in the visible and near-visible light from the Sun is absorbed and warms the Earth and then the Earth emits infrared radiation out towards Space. Although “bounce” is different from “absorb and re-emit” the net effect is the same in terms of energy transfer.
If we assume the balls and traytop are perfectly elastic, and if the well-damped scale does not move once the springs are compressed and equilibrium is reached, there is no work done to the weight scale. Therefore, Energy IN = Energy OUT. The purple balls going out to Space have the same amount of energy as the yellow balls that impacted the Earth.
ADD GHG TO THE “ATMOSPHERE”
Graphic 3 shows what happens when we introduce GHG into the Atmosphere. The yellow balls, representing shortwave radiation from the Sun to which GHG are transparent, whiz right through and impact the weight scale and push it down as before.
However, the purple balls, representing longwave radiation from the Earth, are intercepted by the Atmosphere. In my simplified physical analogy, the Atmosphere splits each purple ball in two, re-emiting one half-ball back towards the Earth and the other half-ball out to Space. Again, you can assume that half of the balls “bounce” off the Atmosphere back to Earth like reflected light from a half-silvered mirror and the other half pass through out towards Space. In the actual case, it is “absorb and re-emit half in each direction” but the net effect is the same in terms of energy transfer.
OK, here is the part where you should pay close attention. The purple half-balls that are re-emitted by the Atmosphere towards Earth impact the tray of the weight scale and press against the springs with about half the force of the original yellow balls. So, at this stage, when equilibrium is reached, the well-damped scale reads “1.5” arbitrary units.
But, we are not done yet. The purple half-balls are absorbed by the Earth, and re-emitted towards Space. Then they are re-absorbed by the Atmosphere and once again split into quarter-balls, half of which head back down to Earth and re-impact the weight scale. Now it reads “1.75”. As you can see, the purple balls continue to get split into ever smaller balls as they bounce back and forth and half head out to Space. The net effect on the weight scale is the sum of 1 (from the yellow balls) + 1/2 + 1/4 + 1/8 + 1/16 and so on (from the purple balls). That expression has a limit of “2”, which is approximately what the scale will read when equilibrium is reached.
Again, the well-damped scale does not move once the springs are compressed and equilibrium is reached, so there is no work done to the weight scale. Therefore, Energy IN = Energy OUT. The purple balls going out to Space have the same amount of energy as the yellow balls that impacted the Earth. But the “temperature” of the Earth, as analogized by the reading on the weight scale, has increased.
DOUBLE THE GHG IN THE “ATMOSPHERE”
Graphic 4 is the final step in my physical analogy. Let us double the GHG in the Atmosphere. (NOTE: I am assuming that the doubling includes ALL the GHG, most especially water vapor, and not simply CO2!) This is represented by putting a second layer of Atmosphere into the physical analogy.
The purple balls emitted towards Space by the first layer of the Atmosphere are intercepted by the second layer, where they are absorbed, and smaller balls are re-emited in each direction. The downward heading balls from the upper atmosphere are intercepted by the lower Atmosphere and half is re-emitted down towards the weight scale that represents Earth. Once again, they compress the springs in the weight scale increasing the reading a bit, and are re-emitted back up. The purple balls get halved and bounce around up and down between Earth and the two layers of the Atmosphere, further increasing the reading on the scale once equilibrium is reached.
Again, the well-damped scale does not move once the springs are compressed and equilibrium is reached, so there is no work done to the weight scale. Therefore, Energy IN = Energy OUT. The purple balls going out to Space have the same amount of energy as the yellow balls that impacted the Earth. But the “temperature” of the Earth, as analogized by the reading on the weight scale, has increased due to the doubling of GHG in the Atmosphere.
WHAT I LEFT OUT OF THE PHYSICAL ANALOGY
Any simplified analogy is, by its very nature, much less than the very complex situation it is meant to analogize. Here is some of what is left out:
- My purple balls are re-emitted in only two directions, either up or down. In the real world, longwave radiation is emitted in all directions, including sideways.
- My purple balls are all totally absorbed by the Atmosphere and re-emitted. In the real-world, a substantial amount of longwave radiation is re-emitted from the Earth and the Atmosphere in the 9μ to 12μ band where the Atmosphere is nearly-transparent. A substantial portion of the radiation from Earth and the Atmosphere thus passes through the Atmosphere to Space without interception.
- My physical analogy addresses only radiative energy transfer. In the real-world, energy transfer from the Sun to Earth and Earth to Space is purely radiative. However, the Earth transfers a considerable amount of energy to the Atmosphere via convection and conduction, in the form of winds, precipitation, thunderstorms, etc. These effects are absent from my analogy.
- I represent the Atmosphere as a single shell, when, in fact, it has many layers with lots of interaction between layers.
- I represent doubling of GHG as adding another shell, when, in fact, doubling of GHG, if it occured (and if it included not just CO2 but also a doubling of water vapor and other GHG) would increase the density of those gases in the Atmosphere and not necessarily increase its height significantly.
- In my analogy, all the energy from the Sun strikes and is absorbed by the Earth. In the real-world, up to a third of it is reflected back to Space from light-colored surfaces (albedo) such as snow, ice, clouds, and the white roof of Energy Secretary Chu’s home :^). If a moderately warmer Earth, due to increased GHG, evaporates more water vapor into the atmosphere, and if that causes more clouds to form, that could increase the Earth’s albedo to counteract a substantial portion of the additional warming.
I am sure WUWT readers will find other issues with my physical analogy. However, the point of this posting is to convince those WUWT readers, who, like Einstein, need a physical analogy before they will accept any mathematical abstraction, that the atmospheric “greenhouse” effect is indeed real, even though estimates of climate sensitivity to doubling of CO2 are most likely way over-estimated by the official climate Team. When I was an Electrical Engineering undergrad, I earned a well-deserved “D” in Fields and Waves because I could not create a physical analogy in my overly-anal mind of Maxwell’s equations or picture the “curl” or any of the other esoteric stuff in that course. Therefore, those WUWT readers who need a physical analogy are in great company – Einstein and Glickstein :^).
I plan to make additional postings in this series, addressing some implications of the 9μ to 12μ portion of the longwave radiation band where the Atmosphere is nearly-transparent, as well as other atmospheric “greenhouse” issues. I look forward to your comments!
“Steve says:
February 22, 2011 at 12:41 pm
“The temperature is the average speed of all the particles.”
Almost, but not quite. Temp is the average kinetic energy – that’s velocity times mass.”
Almost, but not quite. 🙂 Velocity times mass is momentum. Kinetic energy is 1/2mv2.
THANKS “PJP” – your mention of truckloads of energy in the Willis Eschenbach Topic is what triggered this Topic. Good to “see” you again!
Really? Someone said “It is better to light one little candle rather than curse the darkness.” If I light a candle and take it near the Sun, will the Sun not get even a teeny, tiny bit warmer?
I remember my high-school physics teacher’s interpretation of the first law of thermodynamicss.
He would say “joules equals joules equals joules” while jumping up and down, nearly frothing at the mouth.
Many here are saying that there is a difference between energy and heat, but my physics teacher would disagree.
Another thing is the following which is a quote but I cannot remember the source, but I will follow with an informal proof of the concept. Here goes, difficulty factor pi.
“If all the matter in the universe consisted of stoves and pots of water, then in between a google and a googleplex years, one of the pots would freeze.”
If anyone recognizes that and can lead me to the source, I would be appreciative.
Now for an informal proof
Imagine a volume of gas at a certain temperature, temperature being the average kinetic energy of the molecules of the gas, which exist with differing velocities according to the Maxwell-Boltzmann distribution. Now if we let time advance and collisions between the gas molecules to occur, it would be reasonable to believe that when two molecules collide with initial velocities a and b, one faster than the other such that a > b, then after collision, the velocities would be a1 which would be lower than a and b2 which would be higher than b2. Then continuing, after a finite amount of time the velocities of all the molecules would be the same.
But, since this does not happen, because gases maintain the maxwell-boltzmann distribution, thus it is unreasonable to conclude that two molecules that collide always transfer energy from the faster molecule to the slower, sometimes a slower molecule increases the energy of a faster molecule.
And where am I going with all this….
The fact that heat is always transferred from hot to cold is not a fact at all, it is just due in part to chance, it is just more likely.
As for disproving the greenhouse effect, I prefer the essay “Ponder the Maunder”
It varies from instant to instant; if the sun sets (e.g.) while you are outside, you will begin to chill somewhat as the coat’s emissions now exceed absorptions. Then a new balance will be reached, varying around a new lower “set point”. (Variations in breezes, body heat emitted due to exertions, etc.)
Ira Glickstein, PhD says:
February 22, 2011 at 6:38 pm
“During the morning rush hour, 100,000 cars come into the city and 10,000 go out of it. The NET flow is 90,000 cars into the city. However, as anyone who cares to look will see, there is a flow in both directions, both into and out of the city.”
———————————-
You didn’t quite appreciate what my metaphor was about. It was not trying to represent radiation of energy. You can step on the gas and the brake at the same time but you can’t speed up and slow down at the same time.
I was just saying that although something can be sweet and sour at the same time, it can’t be hotter and colder at the same time. If a hotter object is heating a cooler object a lot and the cooler object is heating the hotter object a little at the same time that the cooler object is cooling the hotter object a lot and the hotter object is cooling the cooler object a little, we have landed on planet Gore and we probably will burn up.
In reply to Dan’s post (circa February 22, 2011 at 12:04 am);
The zero degree was a hypothetical “temperature” that was chosen to align with the original authors “scale” where zero was the initial condition, i.e. the average temperature of the Earth’s surface (~255K). It is not meant in any way to represent zero degrees Kelvin.
I am still waiting for info about how the laws of thermodynamics do not apply to electromagnetic radiation.
Cheers, Kevin.
“”””” bob says:
February 22, 2011 at 6:54 pm
I remember my high-school physics teacher’s interpretation of the first law of thermodynamicss.
He would say “joules equals joules equals joules” while jumping up and down, nearly frothing at the mouth.
Many here are saying that there is a difference between energy and heat, but my physics teacher would disagree. “””””
I can’t even imagine just where you found that; because I don’t recall anybody asserting that. “Heat” is certainly a form of energy; and I don’t think anyone here has denied that. In particular it is the kinetic energy of molecules that are at a Temperature above absolute zero, and in fact the Temperature is defined in terms of that energy; specifically the mean energy per degree of freedom.
So you simply have been misreading what people have been writing. Now there have been several including me; who have said that Heat (energy) and electromagnetic radiation energy are NOT the same; so what did your Physics teacher tell you about that ?
So what is YOUR interpretation of the First Law of Thermodynamics; now that your teacher, apparently has taught that to you ?
As for your “proof” bob, that heat only sometimes by chance, moves from high Temperature to low Temperature; there’s a snag in your argument; because that Temperature is defined in terms of the mean energy per degree of freedom of a large assemblage of molecules; not of a single molecule. It is true, as I have also argued, that the statistical distribution (Maxwell-Boltzmann) of kinetic energies of a large assemblage of molecules (at a given Temperature), is identical to the time distribution of the energy of any single molecule; averaged over a suitably large time interval.
Since the M-B distribution is a map of where (energy wise) any molecule of the set can be found at any instant, and over time any particular molecule could be found at any location in that distribution; therefore one can argue that the Temperature is also the time averaged energy of any single molecule in the set.
But your snag is still there, because the time averaged energy distribution of any single molecule loses any information about any single inter molecular collision such as the collision you described.
So your proof, is no proof of anything; other than that you do not understand the problem.
“”””” Kevin (not a PHD) says:
February 22, 2011 at 7:22 pm
In reply to Dan’s post (circa February 22, 2011 at 12:04 am);
The zero degree was a hypothetical “temperature” that was chosen to align with the original authors “scale” where zero was the initial condition, i.e. the average temperature of the Earth’s surface (~255K). It is not meant in any way to represent zero degrees Kelvin.
I am still waiting for info about how the laws of thermodynamics do not apply to electromagnetic radiation.
Cheers, Kevin.
Well Kevin (not a PhD); you do not need a PhD to know that the statement of yours above is nonsense. There is nothing at all hypothetical about absolute zero; and there are no degrees Kelvin; just simply Kelvins; and zero Kelvins IS the absolute zero of Temperature and in no way hypothetical.
Perhaps you could describe for us, some of your own investigations at Temperatures lower than your hypothetical and quite arbitrary zero Kelvins; and it is not and never has been related in any way to the average Temperature of the Earth surface; or of any other planet.
So specifically which Law of Thermodynamics is Electromagnetic Radiation related to.
Shall we start with the zeroth law first:- “All systems which are in thermal equilibrium with a given third system, are also in mutual thermal equilibrium.”
So when was the last time you encountered an electromagnetic field that was in any kind of equilibrium; and specifically thermal equilibrium; which would require it to have a specific Temperature. No I don’t think the zeroth law is any help.
Maybe the First Law of Thermodynamics:- “The total internal energy of a system is a conserved quantity. Energy cannot be created or destroyed, but only transferred from one system to another.” My that is not quite the same as your Physics teacher’s mouth frothing version. Well Photons can certainly be created and destroyed, as can Electromagnetic waves as described my Maxwell’s equations. Dosen’t look like the first law applies to electromagnetic radiation either.
Well I’ll let you take a look at the others yourself to see what you can come up with; maybe you could review it with your frothing Physics teacher.
Here (IMHO) is the “money quote” from PJP;
“But this is NOT new energy. It is energy that has already been accounted for and should NOT be re-counted.”
With respect to the original author I would like to edit this quote “But this is NOT new energy. It is energy that has already been accounted for and ACCORDING TO THE LAWS OF THERMODYNAMICS CANNOT, REPEAT CANNOT be re-counted.”
In my opinion this is EXACTLY the flaw in the “greenhouse theory” you cannot count the energy twice any more than you can count your paycheck twice (at least legally that is).
Cheers, Kevin.
To Mr. George E. Smith;
Quoting your comment directly;
“Dosen’t (sic Doesn’t) look like the first law applies to electromagnetic radiation either.”
Again I respectfully suggest you provide references.
All of my training teaches me that the First Law of Thermodynamics (and all of the other laws as well) apply to all forms of electromagnetic radiation. Sorry, I realize now that this might shatter your belief in the “greenhouse effect”, but these are the facts. I did not invent them, I’m just relaying them to you and others that may or may not be receptive to them.
Again the “scale = 0” analogy was based on the original authors choice of “scale weight reading (analogous to the surface temperature)”, this is the original text, hopefully quoted accurately. This does not (as far as I can interpret the original author’s intent in any way represent the “hypothetical” 0 degree Kelvin case). As an aside 0, (zero) degrees Kelvin is still (as far as I know) a hypothetical situation that nobody (including myself) has ever achieved.
Cheers, Kevin.
@ur momisuglyIra – re candles and the sun: I can’t be absolutely, 100% certain, I am not a physicist, but do try to understand some of the basics, even if that may be without a complete grasp of the fundamentals – life is just too short, and I made the decision a long time ago to drop my university career as a physicist to study other topics which I found more interesting.
That said, I do have a grasp of how heat (energy) moves through exciting molecular state, and there really is a minimum amount of energy required to do this.
So, sadly, no, I do not believe that a candle held near the sun will warm it just one tiny bit.
——-
@ur momisugly Kevin – I don’t argue that there is an effect which an atmosphere has which keeps the surface of a planet warmer than it would be without one. I will even go so far as to say that I further buy into the idea that different gases will have different effects, and that gases which are opaque at certain frequencies which coincide with the frequency of radiation from the planet will work better at keeping the planet warm than a gas which does not exhibit those properties.
However, I consider the term “greenhouse effect” a misnomer, and that has probably contributed to more misunderstanding and argument than any other single item.
A greenhouse’s warming effect is predominantly due to its impeding convection, not impeding specific frequencies of radiation. The Earth’s atmosphere has no such effect.
What the atmosphere is, is an insulating blanket. A special sort of insulating blanket.
It has lower insulating properties for higher frequency radiation than it does for lower frequencies. This is mostly due to H2O rather than CO2, but I won’t deny that there is some small contribution by CO2.
But back to the point you originally commented upon – yes, there is only one energy input (the sun), energy can be (and will be) shuffled around by the atmosphere, but that shuffling will never add more energy. In fact, it will absorb some, because moving around the atmosphere (and the seas) takes energy, and that comes from only one source (well … not true, there is the radioactive decay at the center of the Earth, but in comparison I think we can ignore it for this discussion).
So The atmosphere will actually remove some small fraction of the energy input, but NEVER, EVER add to it.
George E. Smith says:
“Now there have been several including me; who have said that Heat (energy) and electromagnetic radiation energy are NOT the same; so what did your Physics teacher tell you about that ?”
Let’s see, since heat capacity is commonly measured in Joules per Kelvin, thus heat can be measured in joules as in you need x amount of heat in joules to raise the temperature of y from z to d. And although electromagnetic radiation is normally specified by its wavelength or frequency, I’ll leave it to you to verify that joules works just as well.
The first law is commonly stated that “energy can neither be created nor destroyed only altered in form”
And do you believe that heat cannot be transferred from a cold object to a warmer one?
And since you brought up degrees of freedom, I’ll assume you know that a photon can have but three, 2 for the direction it is traveling and one for the joules.
And the macroscopic properties of matter must be consistent with the microscopic properties, do you agree?
Cheers
“George E. Smith says:
February 22, 2011 at 8:01 pm
Well Photons can certainly be created and destroyed, as can Electromagnetic waves as described my Maxwell’s equations. Doesn’t look like the first law applies to electromagnetic radiation either.”
If an electron goes from the third energy level of hydrogen to the second, a photon is created, but the hydrogen atom loses the same amount of energy. Conversely, if this same photon hits another electron in the second energy level of another hydrogen and knocks it to the third level, the photon is destroyed but the hydrogen atom gains the same amount of energy. Do you agree?
Kevin,
My point was that there will be more photons emitted after the first one, with a corresponding drop in temerature of the emitter. If the first photon for some reason returns to the emitter it will find the emitter several “photons” cooler than when it left.
It would then be possible for it to heat the emitter to some degree.
There will of course be no net increase in energy or temperature, only a lower rate of cooling.
We need to somehow explain why cloudy nights are warmer than clear nights and other similar phenomena.
Your comment is appreciated.
First, thank you for taking the time to answer so thoroughly. This is starting to make sense to me.
If I can rephrase what you’ve said: “heat” is the excess or additional excitation caused by radiative energy. (I’m not going to worry about conductive or any other form at the moment.)
Going by what I understand so far, it would seem that the cooler object influences the way the warmer object cools by slowing down the cooling,, but that the colder (or less energetic) the cooler body is, the less it slows down the cooling of the warmer body.
Both are radiating “back and forth,” which means that some of the energy lost by the warmer body is being replaced by the cooler body. The less energy from the cooler body, the less energy is fed back into the warmer body, and hence the less heat.
But in that case, it still seems as though “heat” is being exchanged.
Here’s what I’m seeing, and maybe you can correct my impression:
Body A is really hot. That means that it has absorbed a batch of energy causing its molecules to buzz all over the place. This movement is called “heat.” Now, Body A is also all alone. There may be another body somewhere else in the universe, but for all practical purposes, it’s just sitting there somewhere in between galazies.
Some of Body A’s energy is being radiated out in discreet quantum, and this energy never comes back. Every bit of energy simply shoots out in a straight line, never to return.
Now along comes Body B. Body B has absorbed less energy than Body A, therefore its molecules are buzzing around a lot more slowly. But they’re still buzzing. Body B takes up position close to Body A. Now some of the energy from Body A is getting absorbed and re-emitted by Body B, and some of the re-emitted energy is going back to Body A. As a result, Body A is becoming cooler at a slower rate than when it was all alone. The less heat Body B has, the faster Body A will cool, because it will be more like being alone. The more heat Body B has, the slower Body A will cool.
Does this make sense? Or am I still missing something?
Hi Ira, and thanks for trying to help clarify this for me. I’ve been somewhat enlightened by Oliver’s explanation, which is helping me understand the conceptual difference between heat and energy.
Now you are saying that “heat” is a measurement of net flow. I think this may now clarify an error I was making in my understanding of Oliver’s explanation.
To use another analogy, as long as my business is bringing in more money than it’s putting out, it is making a “profit.” The amount of this profit may increase or decrease, but as long as more money is coming in than going out, I still have a profit.
Am I close?
Living In The Lag
What Ira’s cartoon mostly lacks is the 4th Dimension: time.
In my Gedanken Experimental revisualization, we start with the Earth just a few degrees below its historic minimum; the exact number is unimportant.
*But it is shielded from the Sun totally (by, shall we postulate, an angled omni-mirror that bounces away any outgoing radiation into deep space off the ecliptic).
*Then, suddenly, the mirror is withdrawn, and a short time later the wave front(s) of radiation from the sun begin impinging on the planet.
*SW is absorbed by the surface and some is re-radiated in the CO2 signature band (~15μ), and absorbed and re-radiated, etc., eventually resulting in some form of outgoing radiation of equivalent energy. This is the LAG period, let’s call it Lp.
*From that moment on, the outgoing radiation matches incoming (averaged over a few multiples of Lp).
* But the energy level in the atmosphere and on the surface is higher by the total emitted as 15μ for one Lp’s duration. This has a slight warming effect.
It should be a fairly direct exercise to calculate, to a reasonable approximation, the temperature impact of such emission over one Lp. That is the total we’ve “borrowed” from the first moments the mirror was zipped out of the way.
* Note that if the mirror is suddenly (instantaneously, Gedanken-wise) zipped back into place there will be continued “Lagged” emission till that little reservoir is drained, and we’d experience another Lag when the mirror is re-removed.
Wayne;
Well, humm. I’m going to have a hard time explaining this to you so bear with me, I have thought much on why these people could possibly think the way they do and the only thing I keep coming up with has to do with what Feynman showed so very clearly with little simple cartoon drawings like Ira has drawn above. See this link:
http://vega.org.uk/video/subseries/8>>>
Sorry Wayne, I didn’t watch the series, and as for your explanation, sorry again, but the links I posted are to the explanations of laws of physics and the mathematical equations that quantify them that you can find in any physics text book. If your explanation is correct then you’ve debunked laws of physics that have been established since 1879 and been verified by experimentation thousands of times. You can hypothesise all you want about how photons do this that or the other, but the amount of energy radiated by a body at a given temperature is governed by those laws, proven repeatedly by experimentation, right down to the later work of Wiens and Planck and others that allow not only calculation of how much energy is radiated at a given temperature, but at what frequencies and the distribution of those. Go back and look at the formulas again – they are independant of the temperature of the surrounding environment.
RichardSmith says:
February 22, 2011 at 1:03 pm
In an idle moment I foolishly returned to this thread. Ira Glickstein PhD’s protegé wants the last word, apparently.>>>
Ira is my protege? I’m flattered. Being as he has a degree in physics, a PhD I understand where as my degree is in….oh yeah. I don’t have one.
‘What did the early settlers use to insulate their houses in the depths of winter? Answer: SNOW!’
So all the photons streaming into the house from the cold snow kept the house warm? Mmm. Food for thought, there, davidmhoffer.>>>
Sigh. No. If there is a heat source in the house, the house will be warmer with snow piled up all around it than with no snow. And, to anwer your next point, yes, if there is no heat source in the house, it will drop in temperature until it is at the same temperature as the surroundings. But it will drop much slower if the house is insulated with snow.
But let’s tackle your most seriously flawed statement:
Use snow as an insulator, or to keep the wind from whistling between the logs, but forget the energy it is radiating. It’s only useful if you are colder than snow.>>>
Someday perhaps you will come winter camping with me? We’ll trudge out into the wilderness and find camp site. You’ll lay your sleeping bag down on top of the snow and I will go to work pushing loose snow into as big a pile as a I can. You’re probably already snoring by the time i finish hollowing out my pile of snow and crawling insider of hit. Now the snow is colder than I am, yet an hour later I’ll probably have to take off my jacket to keep from over heating, maybe even open the sleeping bag zipper. In the morning I come to check on you, see if you’re ready to hike the next leg. Unfortunately you are frozen solid, convinced that the snow of the Quinzee would only help you if you were colder than the snow.
You might argue that my pile of snow, called a Quinzee wouldn’t have warmed up without my body heat. True. And that is the point. Your body heat does warm the snow, and the snow then transmits some of that heat back into the quinzee. Igloos work by the same principle.
The only foolish mistake you made in returning to this thread was to continue commenting.
davidmhoffer says: February 23, 2011 at 4:22 am
‘”In an idle moment I foolishly returned to this thread. Ira Glickstein PhD’s protegé wants the last word, apparently.>>>”
‘Ira is my protege? I’m flattered. Being as he has a degree in physics, a PhD I understand where as my degree is in….oh yeah. I don’t have one.’
David – we’ve abused each other enough by now to be on first name terms – your ability to misread almost everything I write astonishes me. I wrote that you were Ira Glickstein PhD’s protegé, not that Ira Glickstein PhD was your protegé. Perhaps you are being ironic in a really cool, self-deprecating way. I’d certainly lay off the Red Bull for a while.
‘Someday perhaps you will come winter camping with me?’
You old smoothie! But – and here I have to be brutally frank, I’m afraid – there’s a very long list of people (starting with Keira Knightley) that I’d rather go into the woods and melt snow with than you.
Ah! There’s the phone. Must be Keira. Have to dash. Toodlepip! Melt some snow for me!
I have two comments:
First, Ira Glickstein was describing a simple model of radiation and the greenhouse effect, just as Galileo was using a simple model of rolling balls down and up inclined
planes to reach the conclusion that bodies in motion tend to stay in motion unless acted on by a force. The attacks on Glickstein’s model were an irritant to me, like attacking Galileo’s model for ignoring friction which slows rolling balls to a stop in the real world. To understand any phenomena, we’ve got to start simple, as with Galileo’s experiment and Ira Glickstein’s example, and gradually add complicating factors as
we begin to understand the concepts.
Second- regarding Richard Smith and David M Hovver’s snow remarks. We are
confused by snow because it’s white and reflects visible light. In the infrared, snow
acts almost as a black body. That’s why snow melts much more quickly around tree trunks than farther out in the middle of a field.
I want to make another comment by approaching the problem from a reverse angle.
Remember that the sun radiates photons predominantly from 0-5 um.
Here is a paper that confirms to me that CO2 is (also) cooling the atmosphere by re-radiating sunshine:
http://www.iop.org/EJ/article/0004-637X/644/1/551/64090.web.pdf?request-id=76e1a830-4451-4c80-aa58-4728c1d646ec
they measured this radiation as it bounced back to earth from the moon. So the direction was: sun-earth-moon-earth. Follow the green line in fig. 6, bottom. Note that it already starts at 1.2 um, then one peak at 1.4 um, then various peaks at 1.6 um and 3 big peaks at 2 um. You find everything back in fig 6 top (the actual measurements).
Obviously we know that CO2 also has big absorption at between 4 and 5 um and most recently they also discovered some absorptions of CO2 in the UV range. So this is not shown in these graphs but we know about it and it would be there had they been able to measure it with their equipment.
the question: So what exactly happened here?
The sun’s photons hit on the CO2 and found a few places where “it went inside” (absorbed). But once the molecule was filled here (and in a new state), it started behaving like a mirror at that particular wavelength stretch. That is the only way to explain what is happening.
remember: this is the radiative cooling caused by CO2.
Now, CO2 also has absorption between 14 and 15 um. Remember that earth emits predominantly in the 10-20 um range. So we can imagine that when some of earth’s radiation hits on the CO2 at 14-15 um it will be send back to earth. This is what is called the “greenhouse effect”. It will cause some warming just as the deflection of some of the sun’s radiation (away from earth) by CO2 will cause some cooling.
The question is: which is bigger: the cooling or the warming? If the warming is bigger, CO2 is a GHG. But it appears that no one could answer me this question satisfactorily. So I don’t know (exactly).There are no results. It appears nobody knows how to test it.
In addition, CO2 also causes cooling by taking part in photo-synthesis. Namely, forests and greenery need energy to grow. That energy is extracted from their surroundings.
So what is the net effect of the increase in CO2 in the atmosphere? My results seem to indicate that the net effect is zero or possibly even slight cooling.
http://www.letterdash.com/HenryP/assessment-of-global-warming-and-global-warming-caused-by-greenhouse-forcings-in-pretoria-south-africa
I found similar results in La Paz, Bolivia during the dry months there. Also, Willis mentioned Northern Ireland (no change in temps there either).
And in Spain is the same.
If this be true, that would disqualify CO2 as a GHG.
Again, this whole discussion here is meaningless unless somebody proves to me (us) that the net effect of more Co2 is warming rather than cooling.
bob says:
February 22, 2011 at 9:35 pm
George E. Smith says:
“Now there have been several including me; who have said that Heat (energy) and electromagnetic radiation energy are NOT the same; so what did your Physics teacher tell you about that ?”
Let’s see, since heat capacity is commonly measured in Joules per Kelvin, thus heat can be measured in joules as in you need x amount of heat in joules to raise the temperature of y from z to d. And although electromagnetic radiation is normally specified by its wavelength or frequency, I’ll leave it to you to verify that joules works just as well.
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bob,
I’d be interested to hear how heat achieves the construction of sugar moecules in photosynthesis.
Alan McIntire says: February 23, 2011 at 6:17 am
– Well this post started with Einstein and now Ira Glickstein PhD is up there with Galileo. There is no way – no way – that you can use kinetic processes (bouncing balls) as an analogy for thermodynamic processes such as absorption and emission of radiation. No way.
‘To understand any phenomena, we’ve got to start simple’ you write. Well, yes, start simply, by all means, but don’t start wrongly because you will never be right.
– Despite being material enough to be thrown by pitching machine, Ira Glickstein PhD’s balls don’t even obey the laws of motion, such as when they split and one goes upwards and one goes downwards. Don’t know what Sir Isaac (no PhD) would make of that.
– ‘We are confused by snow because it’s white and reflects visible light. In the infrared, snow acts almost as a black body.’
The phrase ‘black body’ describes a radiator/absorber that behaves perfectly in accordance with Planck’s equations and should not be used in other contexts. You seem to be using it here to mean that snow absorbs IR well. Not quite the same thing.