Greenhouse Gases Do NOT Violate The Stefan-Boltzmann Law
| 06-08-2019 19:03 | |
Into the Night ★★★★★(21582) |
tmiddles wrote:tmiddles wrote: A fair description. You can think of it like a perfect mirror but not one that reflects an image of any kind. We use the term 'black' or 'white' because we tend to relate things in terms of light we can see. It's a misnomer. It's a weakness of the language. Frankly, the best way to describe it is with mathematics. A perfect absorber and emitter of light would appear black to us. So black, we couldn't see the object or its surface. A perfect reflector of light would appear as a combination of all light shone at it. So perfect, we couldn't see the object itself or even its surface. Ideally 'white'. tmiddles wrote: The emissivity of each of these surface is unknown. What you see listed here is the ASSUMED emissivity of several surfaces for engineering purposes. tmiddles wrote: Impossible. To measure the emissivity of a surface, first it's temperature must be accurately known at the time of measurement. No one knows the temperature of the Earth. tmiddles wrote: Emissivity is a measured constant. It is not a variable. If you measure it again, you might get a different value, but that value simply becomes the new constant until you measure it again. The Parrot Killer Debunked in my sig. - tmiddles Google keeps track of paranoid talk and i'm not on their list. I've been evaluated and certified. - keepit nuclear powered ships do not require nuclear fuel. - Swan While it is true that fossils do not burn it is also true that fossil fuels burn very well - Swan Edited on 06-08-2019 19:14 |
| 06-08-2019 20:00 | |
IBdaMann ★★★★★(14389) |
tmiddles wrote: So I realize that doesn't really say anything new other than that I'm less confused about vocabulary at this point. That's great! Don't sell that short. In a forum of ideas, words are all you have. Words have meanings. If you don't know what they are then you can be manipulated by people who are aware that you don't know the meanings of the words. Which brings us to the two types of people discussing "Global Warming," "Climate Change" and "Greenhouse Effect." 1) Those who, to some extent, are simply confused about the meanings of some words and therefore are mistaken in formulating their thoughts, opinions and positions 2) Those who wish to convert others to their (religious/political) beliefs and who are inclined to misinform and to otherwise take advantage of their targets' areas of ignorance by pretending to be technically smart/authoritative. For those in category #1, I am happy to help them work through semantics to formulate a clear understanding of the material ... so they can validly support whatever position they take. For those in category #2, I am happy to pick them apart. I usually wait to be called a "troll" or "denier" before the gloves come off. tmiddles wrote: The Earth has a very complex collection of different emissivities which includes the oceans, sand, rock, trees, clouds, atmosphere, and so on. It's not some consistent perfect grey body of some value. You are absolutely correct in the concept you are trying to express. However, in keeping with the theme of "words are all we have" I will offer a rewrite of your statement so that it is correctly expressed: The earth is non-uniform black body, comprised of many different materials and substances. Ergo, the earth's (one and only) emissivity is a function of an incalculable compilation of absorptivity/radiativity signatures. I'm here through Thursday! tmiddles wrote: Also it's the full spectrum of light that matters not what human's notice. Absolutely. I don't know how proficient you are in math, but if you understand integrals then I would point out that the Stefan-Boltzmann law is Planck's law (which is the science that covers the absorptivity of specific substances at specific wavelengths) integrated over all wavelengths. As such, "emissivity" only has meaning within the context of a single body considering all wavelengths. This means we don't speak of the "emissivity" of substances ... we speak of a substance's "absorptivity" at a particular wavelength. If we wish to semantically refer to a substance's absorptivity at each wavelength then we refer to the substance's absorptivity signature. The corresponding radiativity of a substance at a given wavelength ... is equal to its absorptivity at that wavelength ... per Kirchoff's law. This is why there is only one Emissivity term ... because a body's total absorptivity is also its total radiativity. Stefan-Boltzmann simply refers to the aggregate power per area emitted, all wavelengths considered. Emissivity is the coefficient on that so there can be only one for each body. https://www.youtube.com/watch?v=sqcLjcSloXs tmiddles wrote:Material Emissivity Coefficient (link I know you found this on the internet so there is an inclination to take it all on face value. I hope you have a few grains of salt with you when you take it all in. I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist Edited on 06-08-2019 20:01 |
| 07-08-2019 01:13 | |
tmiddles ★★★★★(3979) |
Into the Night wrote: OK this doesn't sound right to me. Emissivity only refers to what is radiated from a body due to the thermal energy in it right? And Kirchoff says that Emissivity = Absorptivity when there is equilibrium. So I thought absorption was the "Absorbing" of the radiation as thermal energy so that it could then feed the loop and be emitted as the emissivity. IBdaMann wrote: Did you mean "Grey body"? And it makes sense it would be one value. Just like I have one weight, doesn't matter how much all my body parts weigh, it's a total. And yes I got that the emessivities of those substances listed online were presented as samples/examples. Obviously all sand won't be the same and so on. Great that is all checking out! Clear so far. So my next step in thinking is what actually gives a body/system a temperature. My understanding is that no thermal energy is permanently "kept", it's always just passing through, that the temperature is the measure of the thermal energy "present" at the time of measuring. Like a traffic report for thermal energy. So in a vacuum a heat lamp is shown onto two balls of the same size and materiel. One is solid and has four times the mass of the other which is hollow. If the setup is the same and the heat lamp shines long enough the two balls will eventually reach an equilibrium at the same temperature? However the hollow ball would have reached this equilibrium much faster, the thermal energy having less mass to flow through. Also if the heat lamp is turned off the sold ball will have thermal energy for longer as it has more thermal energy "present" within it as there is essentially more roadway for traffic to be on. |
| 07-08-2019 03:03 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote: OK this doesn't sound right to me. Emissivity only refers to what is radiated from a body due to the thermal energy in it right? Nope. Take an energy source, e.g. the sun. Take a body, e.g. the earth. The energy source's radiance emits electromagnetic energy towards the body, i.e. the sun radiates towards the earth. You do your geometry and calculate the amount of the sun's radiance that is emitted towards the earth, and then you apply the inverse square law to determine the strength of the radiance that actually strikes the earth. Let's call this value Incident_Radiance. But every body has an emissivity. Let's pretend the earth's emissivity value is 0.72 or 72%. Warmizombies will therefore tell you that the earth's albedo is 0.28 or 28%. This means that the amount of solar energy that is absorbed by the earth is 0.72 * Incident_Radiance and the amount of solar energy that is reflected away (not absorbed) is 0.28 * Incident_Radiance. This also means that when the earth radiates energy off into space, it only radiates 72% of what an ideal black body would radiate. Why? Because the earth's absorptivity is exactly equal to the earth's radiativity, hence emissivity is the only term needed for both absorptivity and radiativity, because it's both. tmiddles wrote: And Kirchoff says that Emissivity = Absorptivity when there is equilibrium. No. The absorptivity of a substance is always the same as its radiativity. There is no thermal equilibrium requirement. tmiddles wrote: So I thought absorption was the "Absorbing" of the radiation as thermal energy so that it could then feed the loop and be emitted as the emissivity. Electromagnetic energy, i.e. photons, are absorbed by matter and the form of the energy is changed from electromagnetic to thermal at which point it instantaneously begins changing form back to electromagnetic energy (of different wavelengths) and radiating from the matter per the Stefan-Boltzmann law. tmiddles wrote: Did you mean "Grey body"? I did not. I meant black body. This is where you will be challeneged to not become confused because different people use different words for the same things. I'm old school classical physics. There is no such thing as a "grey body." All bodies are black bodies. The modifier "black" refers to thermal activity. For any given black body you simply find out its emissivity. An emissivity of 1.0 refers to an "ideal" black body and is purely theoretical (none exist in nature). A white body is also a purely theoretical body, emissivity = 0, that does not exist in nature, is necessarily at absolute zero always and is incapable of any thermal activity. At some point some people became confused and began popularizing the idea that a black body was sysnonymous with an "ideal" black body ... and that regular, ordinary non-ideal black bodies, i.e. the kind that actually do exist in nature, must therefore be "grey" bodies. So ... you are going to encounter both kinds of people ... and I fear that those who use the term "grey body" are far more common that I had previously imagined, so if you are conversing with one of them, you need to refer to black bodies as grey bodies and to only "ideal" black bodies as black bodies. If you are speaking to me, the earth is a black body. If you are speaking to someone else, you might need to refer to the earth as a grey body. The key to navigating the semantics is to focus on the emissivity value. If there seems to be confusion, just ask what term is used for a body of emissivity 0.81 and just go with that. tmiddles wrote: So my next step in thinking is what actually gives a body/system a temperature. That's easy. Matter's temperature is it's quantity of thermal energy (distributed over its quantity of mass). The problem is in measuring the temperature. We can't see/discern how much thermal energy there is in matter. We can only make very rough estimates by measuring other things. tmiddles wrote: My understanding is that no thermal energy is permanently "kept", The best way to visualize what's going on is to put a spaghetti strainer under the kitchen faucet. Pretend the strainer is an atom and that flowing water is electromagnetic energy.  When you turn on the spigot, water flows into the strainer and then immediately starts flowing out. Water will accumulate in the strainer however, depending on the rate water is flowing into the strainer. As the rate from the spigot increases, the level of the water rises in the strainer, which causes an increase in the rate at which water pours out of the strainer. At any given moment, the amount of water in the strainer is both its quantity of thermal energy and its temperature (factored for its mass). The water in the strainer is not "trapped" in the strainer and will flow out ... but it will do so based on the amount of water in strainer, just like Stefan-Boltzmann tells us that thermal radiation flows out of matter based on the temperature of the matter. tmiddles wrote: So in a vacuum a heat lamp is shown onto two balls of the same size and materiel. One is solid and has four times the mass of the other which is hollow. So in a kitchen with two identical sinks and two identical spaghetti strainers, you place into one of the spaghettin strainers an inverted metal cone (that doesn't block any of the holes)  If water flows into both strainers equally, they will both reach the same equilibrium level, but because the cone is taking up volume in one of the strainers, less water is required to "fill" that strainer to the equilibrium level and thus it will reach the equilibrium level sooner. tmiddles wrote: If the setup is the same and the heat lamp shines long enough the two balls will eventually reach an equilibrium at the same temperature? Yes, provided they both have the same emissivity (which they do because they are of the same meterial) and are the same distance from the lamp to ensure energy is fowing equally into both. tmiddles wrote: However the hollow ball would have reached this equilibrium much faster, the thermal energy having less mass to flow through. Yes, but because the hollow ball requires less thermal energy to be distributed throughout the "less mass" for it to achieve the equilibrium temperature, so it reaches the equilibrium temperature sooner. tmiddles wrote: Also if the heat lamp is turned off the sold ball will have thermal energy for longer as it has more thermal energy "present" within it as there is essentially more roadway for traffic to be on. Yes. If you turn off the water flowing into the strainers, the strainer with the inverted cone will empty sooner. Key Point: In both cases (strainers and balls), the regulating factor is the fixed surface area through which water/energy can flow. . I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 07-08-2019 03:51 | |
| Into the Night★★★★★ (21582) |
tmiddles wrote:Into the Night wrote: Absorption does not necessarily result in conversion to thermal energy. It may be converted to chemical energy or potential chemical energy. It may be converting a substance into ions directly. It may cause a sympathetic vibration and emission of energy on another frequency of light. Generally, infrared light usually results in conversion to thermal energy. Visible light results in conversion to chemical energy (think photosynthesis, the response of a retina to generate a small amount of electrical energy). UV light may also produce chemical energy (think ozone from oxygen or oxygen to ozone, or suntan or sunburn, or destruction of the retina of the eye). tmiddles wrote:IBdaMann wrote: Some people call it this, but again, this is a weakness of our language. The Earth is not 'grey', it simply is somewhere from being a perfectly 'black' body which we cannot see, and a perfectly 'white' body which we cannot see. Amazingly, we CAN see the Earth. tmiddles wrote: Newton was once asked this same question. He essentially came up with the same answer you just did. He did it by combining all the gravitational effects of all the particles of a representative spherical mass and combined their effect. The center of gravity of all combined masses is at the center of the mass for a spherical mass (like Earth). tmiddles wrote: Many beaches in Hawaii are a beautiful golden color. Some, however, are quite black. These form when a nearby volcano spews massive clouds of molten lava droplets into the air during an eruption, forming what is known as Pele's Tears. They are bits of lava, solidified as they flew through the air. They contain tremendous internal stresses. Walking on a field of Pele's Tears cause little explosions where you break them. It sounds like walking on popcorn. The surf does this for you when it happens on a beach. Pele is the Hawaiian goddess of the Volcano, one six daughters born to Haumea, the Goddess of the Earth, and Kane Milohai, creator of the sky and upper heavens. That union also produced seven sons, according to the religion. tmiddles wrote: I am glad you are cross referencing and searching out what people say now. No one, not even me or IBdaMann, should be taken strictly on our word. But it is important to remember the concepts of philosophy which define words like 'science', 'religion', 'reality', and other similar words. The rules of philosophy are simple: The only requirement is that any argument must also present it's own reasoning for it. That reasoning cannot come from anyone else. It must come from the one making the argument. In other words, things like URLs, quotes, or opinions of others is not part of your reasoning, and therefore is not part of your argument (it is the argument of someone else). Arguing with someone that isn't here on this forum is rather pointless. Unfortunately, most schools suck at teaching philosophy. They have a 'philosophy' class that talks about the sound of one hand clapping, or the sound of a tree falling in the forest an no one is there to hear it, and other nonsensical strange loop scenarios. What they are trying to teach (badly), is phenomenology, a branch of philosophy that defines what 'real' and 'reality' mean. It also describes why an observation is not a proof. tmiddles wrote: A temperature is sort of an instantaneous reading of the average kinetic energy of particles in a system at the time. Thermal energy is the total kinetic energy of particles in a system at the time. Heat is not contained in an object, but thermal energy is. It is always changing too. There is always heat. tmiddles wrote: True, if and only if the balls were the same emissivity on their surface as well. tmiddles wrote: tmiddles wrote: Wups. You confused temperature with thermal energy again. The solid ball has more thermal energy, so there is more heat available from it. The Parrot Killer Debunked in my sig. - tmiddles Google keeps track of paranoid talk and i'm not on their list. I've been evaluated and certified. - keepit nuclear powered ships do not require nuclear fuel. - Swan While it is true that fossils do not burn it is also true that fossil fuels burn very well - Swan |
| 07-08-2019 03:55 | |
| Into the Night★★★★★ (21582) |
IBdaMann wrote:tmiddles wrote: OK this doesn't sound right to me. Emissivity only refers to what is radiated from a body due to the thermal energy in it right? A reasonably nice description using strainers and the cone, but a lot of people would have trouble visualizing the cone taking up space in one of the strainers. It should be mentioned that water is flowing between the cone and strainer, not into the cone itself (which would just act like a funnel). The Parrot Killer Debunked in my sig. - tmiddles Google keeps track of paranoid talk and i'm not on their list. I've been evaluated and certified. - keepit nuclear powered ships do not require nuclear fuel. - Swan While it is true that fossils do not burn it is also true that fossil fuels burn very well - Swan |
| 07-08-2019 05:26 | |
| tmiddles★★★★★ (3979) |
Into the Night wrote: Yes really good descriptions from you both. In my visualization that cone didn't take up much volume since it was a thin sheet metal with water on both sides. I'm realizing what you mean only now. That the cone was not allowing the water to flow out the bottom of the strainer and keeping it along the sides. I think it could also work to say that the strainer for the hollow mass, since it's a smaller mass, is simply shallower. That the volume of the strainer corresponds to the amount of mass. Great so far! So next question: 3 balls, same vacuum and heat lamp, same surface, a shell of steel. A thermometer in the center of each. 3 different insides: Ball 1 is filled with solid steel Ball 2 is filled with solid wood Ball 3 is filled with air Once they have had enough exposure to the heat lamp to reach an equilibrium what would the thermometers tell us? I would think it would go high to low, from steel to air, more matter allowing for more thermal energy to be present. |
| 07-08-2019 05:56 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote: I'm happy to discuss conduction with you, but I just want you to realize that the moment you place the thermometer inside the ball and not at the surface, you are discussing a completely different subject and an entirely different situation from what you might be imagining. . I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 07-08-2019 06:00 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote:tmiddles wrote: No I want it at the center! But for clarity let's have two, one at the surface and one at the center. Imaginary thermometers are very affordable! |
| 07-08-2019 06:05 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote: They all eventually reach the same internal temperature, which is exactly the surface equilibrium temperature. The three balls simply arrive at the equilibrium temperature at different times, starting with ball 3, then ball 2, then ball 1 ... but I could be mistaken about the order of 1 and 2 because I don't know what kind of wood or its properties; I'm just making a bunch of assumptions. . I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 07-08-2019 06:21 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote:tmiddles wrote: No the ramp ups not important. I'm wondering about at equilibrium, solar system style. So no different at any point in the ball regardless of the matter then?. Surface temp too. The temperature being the same though the thermal energy in each ball is different? I'm trying to wrap my head around the relationship between thermal energy, temperature and the density of matter. It seems like you could take a thermometer from solid steel to one atom in a vacuum and the temperature could be the same but the number of thermally energized atoms that can smack into the thermometers sensor would decline as you went. Edited on 07-08-2019 06:46 |
| 07-08-2019 06:52 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote:So no different at any point in the ball regardless of the matter then?. Surface temp too. The inside of each ball is enclosed by a surface of fixed temperature, which is determined by its material's emissivity. All balls have the same surface material so they will all have the same surface temperature which will bring the internal material to that temperature as well. . I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 07-08-2019 07:09 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote: OK that makes sense but the quantity of matter/molecules bugs me. I don't understand how the thermosphere is 1/1000 the pressure of the surface (1 millibar vs. 1000) but can achieve such a high temperature 200C. Since there are far fewer molecules bouncing around don't the molecules that are there have to "work harder" for the same impact(literally impacts) into the thermometer? Wouldn't this mean that the molecules in the air filled ball, being fewer in number/mass, must "work harder" than the molecules in the solid steel ball, per molecule. I am mixing up density and pressure I do see that. When the pressure decreases, then the temperature decreases. It just seems like the molecules of the thermosphere, per molecule, are super crazy thermally energized. I'm still fuzzy on how the density of molecules wouldn't result in higher temperatures even at equal pressure. Edited on 07-08-2019 07:30 |
| 07-08-2019 07:42 | |
| James___★★★★★ (5513) |
tmiddles wrote:IBdaMann wrote: That's wrong. A lead ball might show it has gravity while a ball filled with talcum powder won't. Extremely basic. |
| 07-08-2019 11:16 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote:a shiny iron ball rusts over, then the science considers the rusty ball as a different body with a different EMISSIVITY constant. Just to confirm: For a steel ball exposed to a heat lamp in a vacuum until it reaches it's thermal equilibrium: polished, lower emissivity, lower equilibrium temperature rusty, higher emissivity, higher equilibrium temperature It's the same energy source but in the polished scenario more of it is reflected away. So in the case of predicting a planets temperature you could calculate it for the planet (regardless of it's size or any other attribute) based on it having full emissivity (perfect black body) and assume it'll be something less than that right? IF you knew the emissivity then you'd be able to predict it accurately. Doesn't matter if it's a tiny planet, gassy, no atmosphere, thick atmosphere, or what it's made of or how fast it spins. The emissivity value would boil all of that down to one number (not sure about the spinning part mattering or not, I think not). Edited on 07-08-2019 11:16 |
| 07-08-2019 17:39 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote: For a steel ball exposed to a heat lamp in a vacuum until it reaches it's thermal equilibrium: Let's forget about whether polished steel has a higher or lower emissivity and just focus on two balls of different emissivities. Yes, you are correct. The ball of lower emissivity reaches a lower equilibrium temperature. A theoretical ball of 1.0 emissivity would reach the maximum possible equilibrium temperature (whatever that might be based on the radiance of the heat lamp) whereas a theoretical ball of 0.0 emissivity would remain at equilibrium temperature of absolute zero. All other emissivities would reach equilbrium temperatures in between, with higher emissivities having higher equilibrium temperatures and lower emissivities having lower equilibrium temperatures. Don't fall into the trap of assuming that shiny, visible-light-reflecting materials must also reflect infra-red and ultra-violet. Yes, bodies with rusted steel surfaces usually have higher emissivities than bodies with unoxidized steel surfaces, but not always. And different materials exhibit greatly varying absorptivities in different frequency bands so you would be unwise to simply assume based on the shininess of the surface in the visible light spectrum. Of course, if you have nothing else on which to base a guess and you have to bet money in the Vegas sports book, then shininess can increase your odds of getting it right, but it is not a rule. tmiddles wrote: So in the case of predicting a planets temperature you could calculate it for the planet (regardless of it's size or any other attribute) based on it having full emissivity (perfect black body) and assume it'll be something less than that right? Yes. You could do your math, do your geometry, calculate the amount of solar energy incident to a particular planet, apply the inverse-square law ... and then inverse Stefan-Boltzman for Temperature with an emissivity of 1.0 to get an upper limit for the planet's possible temperature. The planet's actual temperature would be strictly less than that amount. How much less? You have no way of knowing or of calculating to any usable margin of error *but* you would at least have an upper limit and you would know that it cannot be absolute zero. tmiddles wrote: IF you knew the emissivity then you'd be able to predict it accurately. Yes. Presuming you had the exact emissivity, you would then be able to calculate the planet's temperature to the same accuracy as your radiance value. If you are talking about earth and you were to have earth's exact emissivity and to know the sun's radiance to +/- 6% then your margin of error for earth's temperature would be +/- 6%. tmiddles wrote:Doesn't matter if it's a tiny planet, gassy, no atmosphere, thick atmosphere, or what it's made of or how fast it spins. The emissivity value would boil all of that down to one number (not sure about the spinning part mattering or not, I think not). Correct. I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 08-08-2019 01:12 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote: On that note I seem to recall hearing often that an ice age Earth with all that white ice would be reflecting a lot of radiation away but ice actually has a high emissivity. The only significant "reflector" we have would seem to be clouds and gases. So the Stephan-Boltzmann Law is for the "surface temperature" correct? But defining "surface" is in order. Wouldn't it be everything that the radiant energy is interacting with? So the entire atmosphere, the land surface including some of it's depth, and some but not all of the water? Edited on 08-08-2019 01:22 |
| 08-08-2019 05:20 | |
| Into the Night★★★★★ (21582) |
tmiddles wrote:IBdaMann wrote: Not necessarily them either. The Parrot Killer Debunked in my sig. - tmiddles Google keeps track of paranoid talk and i'm not on their list. I've been evaluated and certified. - keepit nuclear powered ships do not require nuclear fuel. - Swan While it is true that fossils do not burn it is also true that fossil fuels burn very well - Swan |
| 08-08-2019 06:00 | |
| tmiddles★★★★★ (3979) |
Into the Night wrote: hmmmm. Edited on 08-08-2019 06:01 |
| 08-08-2019 06:12 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote:So the Stephan-Boltzmann Law is for the "surface temperature" correct? But defining "surface" is in order. All of black body science, of which Stefan-Boltzmann is a part, is a focus on "the radiating surface area" and "the absorbing/reflecting surface area." Into the Night has already touched on the idea that fluids associated with a bogy, e.g. an atmosphere, a lake, etc., are not solids and do not have fixed surfaces. As such, individual molecules are the representative surfaces, as difficult to discern as they are. Black body science/laws (Stefan-Boltzmann, Planck's, Kirchoff's, Wein's, etc) all apply to all matter, always, everywhere. Pick some matter in the universe, any matter at all ... it all applies. Hot matter deep in the earth is radiating into the matter on top of it. You just need to define your "surfaces" if you want to specify what is going on. I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 08-08-2019 06:34 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote:an atmosphere, a lake, etc., are not solids and do not have fixed surfaces. As such, individual molecules are the representative surfaces OK that makes sense. So when you say "the surface area" in the case of earth that does not mean ground level, sea level or any particular position with respect to altitude. It means everything that is in a position to radiate correct? If it is able to radiate directly into space it's a surface. If it can only radiate into more matter, which is also part of the body in question, then it is beneath the surface. So question: A 3" solid steel ball has a 4" steel shell enclosing it, with a void/vaccum between them. A heat lamp shines on the shell. The shell converts the radiance to thermal energy and begins to radiate it back out. But the shell doesn't know up from down so it also radiates into it's own center, across the void, and that radiance hits the solid steel ball inside. The steel ball now has it's own black body reality inside of the shell. As a unit, the ball and shell are, from an outsiders perspective, just one black body, the shell. But if you are inside, on the ball, you have a different point of reference. Now my understanding is that from the surface of the shell, in the long run, it doesn't matter what is going on inside, it could be solid steel, or have nothing but void, it's black body emission is the same once equilibrium is reached. But inside, on the surface of the steel ball, there is a separate equilibrium playing out. |
| 08-08-2019 18:31 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote:So when you say "the surface area" in the case of earth that does not mean ground level, sea level or any particular position with respect to altitude. It means everything that is in a position to radiate correct? Yes. Correct. But then we take them all together and consider them as just one "earth" (the black body in question) because we aren't going to try to track every single photon through its path through every molecule, ... and we don't have to! The good news is that Stefan-Boltzmann allows us to lump everything together and determine the total sum radiance of a body based solely on its average temperature and its emissivity. Granted, depending on the complexity of a body, both of these can be difficult to impossible to determine accurately, but orders of magnitude less impossible than trying to track every single photon through every single molecule. tmiddles wrote: Yes, the atmosphere You are spot on. Of course that's what's really going on, but black body science is powerful and allows us to simplify by grouping everything together as "the body." It's great how that works. tmiddles wrote: So question: Correct. You have the choice of treating the ball+shell as one black body (at which point your focus is on the outer surface of the shell) or of examining the inner ball as a black body at which point your focus will be on the surface of the ball. If I may, I'd like to tie this to Global Warming. Let's say the heat lamp raises the outer shell and the inner ball to an average 80degC equilibrium temperature through and through. Suddenly, the inner ball has a strange chemical reaction going on in its core that greatly heats the inner ball's temperature to a 475degC equilibrium. It gets red hot and starts really radiating towards the outer shell, increasing the outer shell's temperature, thus increasing the radiance of the outer shell back towards inner ball. Question: What science governs this thermal feedback and what will be the inner ball's final equilibrium temperature? tmiddles wrote: Now my understanding is that from the surface of the shell, in the long run, it doesn't matter what is going on inside, it could be solid steel, or have nothing but void, it's black body emission is the same once equilibrium is reached. Your understanding is correct. tmiddles wrote:But inside, on the surface of the steel ball, there is a separate equilibrium playing out. Nope. It's not really separate because it is entirely dependent on the outer surface. The thermal equilibrium temperature of the inner ball will be the exact same thermal equilibrium temperature of the outer shell, it will just be reached some amount of time later. I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 09-08-2019 07:39 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote: Before I explore that question one thing: The AVERAGE surface temperature of the ball is 80 but it's not EVEN. There is the hottest point nearest the heat lamp with the temperature dropping from there around to the dark side. Inside the steel ball would not get to nearly the temperature of the outer shell. You have a thermal relay. I'll talk about it as three participants. The bright side of the outer shell, the dark side and steel ball inside. The bright side gets 100 joules of radiant energy from the lamp. It's converted to thermal energy and starts re-radiating. A total of 40 joules radiate out from the bright side outward and 40 joules inward. 20 joules to the dark side via conduction through the shell. The Dark Side radiating 10 joules outward and 10 inward. Now the ball inside has 40+10 joules radiate to it. 50 joules are converted to thermal energy and immediately begin to radiate out. The ball in the center will basically return what it was given in an even trade. So that the bright side will get 40 back and the dark side 10 back. They'll then radiate this out. So for the shell it's as though it doesn't have an inner surface to radiate from an energy loss stand point. The ratios of thermal energy in equilibrium would be: Bright Side: 50 (100-40-10) Dark Side: 10 (20-10) Ball: 25 ? (50-50) Now in your question the shell and the inner ball will simply swap any radiant energy between them. If the ball send 100 joules to the shell, and the shell radiates 50 back it's actually the same thing that happens if the shell had no void between the shell and the ball in terms of radiance (though then there could be conduction). So the shell arrangement would be the equivalent of a material that couldn't conduct from it's central mass to it's out mass. Preventing conduction is well known as "insulation" because it slows the movement of thermal energy. However you're not talking about insulation of this type living "in a vacuum" as the shell is. So the real question is does it matter that the shell is there at all if the ball heats up? Take the heat lamp out of it for a moment. I think not. It's like having a non-conductive material get hot and radiate. Radiance doesn't care if a material is conductive or not. |
| 10-08-2019 06:15 | |
| tmiddles★★★★★ (3979) |
Quick check I understand this as well: Let's take a heat lamp but give it this adjustability: The frequency of light that it emits can be adjusted from infra red up to ultra violet while the amount of energy is held constant. In a vacuum: Let's take an array of these heat lamps pointed at a solid ball so as to evenly radiate to it at 100 joules per minute (so no dark side). The ball eventually reaches an equilibrium temperature of 100C. The solid ball at this equilibrium temp will emit 100 joules per minute at the wavelength of a body at 100C (373.15 K). Now the Heat Lamps are all taken from a low infra red, then cranked up to ultra violet, down to a visible white light, and played with at different wavelengths of radiation, but always the 100 joules per minute reaching the ball. The ball's temperature and it's wavelength of emission are unchanged through all of this as the same quantity of energy, 100 joules per minute, is converted to thermal energy and re-emitted at the wavelength corresponding to 100C. For the ball, since it absorbs the full spectrum of radiation from the lamps equally well, it doesn't care what wavelengths it's getting, it will always emit based on it's temperature. So while it's equal energy in to energy out the wavelength of input radiation can be erratic while the output radiation is as steady as the temperature of the ball. Correct? Edited on 10-08-2019 06:17 |
| 10-08-2019 12:06 | |
| tmiddles★★★★★ (3979) |
tmiddles wrote:IBdaMann wrote:...heats the inner ball's temperature to a 475degC equilibrium. It gets red hot and starts really radiating towards the outer shell, ... I was thinking more about this. The heated ball with and without a shell and pulses of 100 joules of energy entering into it. Assuming that it will emit 100 joules of energy over a 4 second period. Without a shell: Ball emits 100 joules over a 4 second period and they go straight out into space unimpeded. Ball 1 -25 2 -25 3 -25 4 -25 Total -100 With a shell: Ball emits 100 joules over a 4 second period, they are transferred to the shell that takes one second to absorb and re-emit a joule. Due to the handing back of 12.5 joules each time it ends up taking 7 seconds for the 100 joules to make their exit. Ball..................Shell 1 -25................+25 2 -25 (+12.5).....+25, -12.5in, -12.5out 3 -25 (+12.5).....+25, -12.5in, -12.5out 4 -25 (+12.5).....+25, -12.5in, -12.5out 5 -25 (+12.5).....+25, -12.5in, -12.5out 6 -25 (+12.5).....+25, -12.5in, -12.5out 7 -25 (+12.5).....+25, -12.5in, -12.5out Total -100 (-175+75) If I feed 100 joules per second into the ball without a shell and it take 4 seconds for that pulse of energy to leave then that's a thermal energy total of 250 joules at any instant. Example with the pulses lettered and the energy loss shown Seconds____1____2____3____4____5____6____7 A________ 100__75___50___25____0____100__75 B__________0__100___75___50___25____0___100 C_________25___0___100___75___50___25____0 D_________50___25___0___100___75___50___25 E_________75___50___25____0___100___75___50 Total--------250---250---250---250---250---250---250 If I feed 100 joules per second into the ball and it take 7 seconds for the energy to leave then that's a thermal energy total of 400 joules at any instant. Seconds____1____2____3____4____5____6____7 A_________100__86___71___57____43___29___14 B__________0___100__86___71____57___43___29 C_________14___0____100__86____71___57___43 D_________29___14____0___100___86___71___57 E_________43___29___14___0____100___86___71 F_________57___43___29___14____0___100___86 G_________71___57___43___29____14____0___100 H_________86___71___57____43___29___14___0 Total--------400---400---400---400---400---400---400 So the ball has a higher temperature with the shell, 400 joules present vs. 250 Edited on 10-08-2019 12:47 |
| 10-08-2019 15:11 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote:For the ball, since it absorbs the full spectrum of radiation from the lamps equally well, it doesn't care what wavelengths it's getting, it will always emit based on it's temperature. No. This is not the case. Different materials have different absorptivities for different wavelengths. Notice that the sun does not focus one particular frequency band on the earth and then shift that band to another and then back again. The sun radiates a more or less fixed signature. In the hypothetical example you have given, the outer shell and the inner ball are of a simple material construction, i.e. steel. As the heat lamp radiance shifts from one wavelength to another, the shell/ball's absorptivity changes ... thus it's equilibrium temperature changes. So for the moment, let's return to my question and remove all heat lamps. In deep space, the outer shell (and the inner ball) are in a uniform infrared radiation field that maintains both at 80degC through and through. Suddenly, the inner ball has a strange chemical reaction going on in its core that greatly heats the inner ball's temperature to a uniform 475degC. It gets red hot and starts really radiating towards the outer shell, increasing the outer shell's temperature, thus increasing the radiance of the outer shell back towards inner ball. Question: What science governs this thermal feedback and what will be the inner ball's final equilibrium temperature? I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 11-08-2019 01:47 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote: I was thinking of a "perfect black body" and forgot we'd started with steel. But am I correct that the body will absorb whatever frequencies but it will emitt a frequency independent of what it got? It will emit solely based on it's temperature? So a body could get 100 joules of white light it fully absorbs and 100 joules of infra-red light it full absorbs in alternating bursts and it would be no different than if it was only one frequency at 100 joule bursts? (if it absorbs both equally well) So I realized I have a fundamental question about the ball with the shell heating up first. You said: "infrared radiation field that maintains both at 80degC through and through" How does that work? The radiation field means it's all radiation external to the shell correct? So right off the bat we have to establish how the ball and shell would have the same thermal energy per gram before the balls flare up. So if radiation hits the shell, the shell reaches a temperature and then radiates out, both inward to the ball and outward, the emission inward is 1/2 of what it got. It trades this with the ball inside evenly but the ball is getting 1/2. You can see how this would be the first hurdle for me to get clear. Another setup: A plate in space has a temperature 500C, there is open space on either side, it's emission is based on the emissivity of both sides of the plate and it is able to radiate at let's say X. Setup similar to the shell+ball: The same plate has another plate behind it that returns any energy that it gets from the first plat. It effectively prevents the first plate from using one side to release energy. So it radiates now at 1/2X So the shell is of course only able to use it's outer surface as it's effective emissivity since it's internal radiaton is just handed back. but I can't get past thinking that this is the case: Ball in radiation that would cause 80C is 80C Ball with shell in the way would be 40C?? I know that doesn't sound right but I hope the hang up I'm having is clear. I don't know how to talk about what would happen with your experiment without clearing up this shell interference thing. |
| 11-08-2019 03:08 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote:I was thinking of a "perfect black body" and forgot we'd started with steel. But am I correct that the body will absorb whatever frequencies but it will emitt a frequency independent of what it got? It will emit solely based on it's temperature? You are correct. An ideal black body absorbs all energy, independent of wavelength, which is converted to thermal energy (temperature) which determines the radiance. The spectral graph of a body's radiance across the wavelength domain will be determined by the material of the body. An ideal black body, however, is of a theoretical material that doesn't exist in nature so its graph will always be of this shape:  tmiddles wrote: How does that work? The radiation field means it's all radiation external to the shell correct? Yes. Correct. Physicists use the term "field" when the source and direction of the energy is irelevant and the geometry can be taken out of the equation. If I were to ask you to describe what happens when you put food in a microwave oven, you could make it simpler by referring to the microwave "field" inside the oven. Imagine that there are a bajillion heat lamps all around and the IR is coming in from all angles, and is uniform at all points. It makes it so much easier to not be worrying about specific energy sources or which side of the ball is absorbing, etc.... just a uniform IR field currently maintaining the outer shell and the inner ball at 80degC. Then the inner ball experiences a chemical reaction and shoots up to 475degC , becoming red hot, radiating into the outer shell, increasing the temperature of the outer shell and increasing the outer shell's radiance back to the inner ball. Describe what happens to the temperature of the inner ball based on the increased radiance of the outer shell. tmiddles wrote: So if radiation hits the shell, the shell reaches a temperature and then radiates out, both inward to the ball and outward, the emission inward is 1/2 of what it got. How can that be? Isn't radiance determined by temperature? If the outer shell is 80degC, the radiance outward has to be the same as the radiance inward, i.e. whatever the radiance for 80degC is, no? tmiddles wrote: I don't know how to talk about what would happen with your experiment without clearing up this shell interference thing. Give me your best shot and we'll talk about it. The answer is simple and straightforward. Hint: Think about the warmizombie arguments for Global Warming involving "thermal feedbacks." I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 11-08-2019 07:09 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote:tmiddles wrote: So if radiation hits the shell, the shell reaches a temperature and then radiates out, both inward to the ball and outward, the emission inward is 1/2 of what it got. The 80 deg C is a measurement of the temperature for the mass. I was say in 1/2 the energy. I can have a 80 deg Penny and an 80 deg metal trash can lid and each has a very different amount of energy radiating off of it. So I have my shot at the shell/ball in a field of radiation above but here it is pasted by itself: The Field is exposing anything in it, the outer surface only, to the radiation which would bring a perfect black body to 80 C. This radiation hits the shell, the shell reaches a temperature and then radiates out, both inward to the ball and outward, the emission inward is 1/2 of what it got. It trades this with the ball inside evenly but the ball is getting 1/2. So the shell is of course only able to use it's outer surface as it's effective emissivity since it's internal radiation is just handed back. but I can't get past thinking that this is the case: Ball in radiation that would cause 80C is 80C Ball with shell in the way would be 40C?? because it only get's 1/2 of what the shell puts out. |
| 12-08-2019 03:29 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote:a uniform infrared radiation field that maintains both at 80degC through and through. So I got to get a handle on this first. Could you, in a real experiment, have a sheet of tinfoil and a heavy iron ball covered with tin foil, in a box of heatlamps, achieve the same temperature at equilibrium? And it wouldn't change if they had a shadow between them? They would emit the same radiation as the heat lamps? |
| 13-08-2019 00:36 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote:I can have a 80 deg Penny and an 80 deg metal trash can lid and each has a very different amount of energy radiating off of it. But they cannot differ if they are both of the exact same material, as with the steel outer shell of your example. tmiddles wrote: The Field is exposing anything in it, the outer surface only, to the radiation which would bring a perfect black body to 80 C. This radiation hits the shell, the shell reaches a temperature and then radiates out, both inward to the ball and outward, the emission inward is 1/2 of what it got. It trades this with the ball inside evenly but the ball is getting 1/2. Actually, radiance is power over surface area. The outer shell has a non-zero thickness ergo the surface area inside is strictly less than the outer surface area of the outer shell. So the inner ball will receive the same radiance, it cannot receive the same amount of energy as is radiated outward. tmiddles wrote: Ball with shell in the way would be 40C?? because it only get's 1/2 of what the shell puts out. No, everything would eventually reach equilibrium at 80degC. btw ... you did what I asked in considering warmizombie arguments for Global Warming ... and that involves the claim that IR from the surface is absorbed by atmospheric CO2, with half radiated out to space and half "re-radiated" back to earth, warming the surface, yes? ... but then the inner ball experiences a chemical reaction and shoots up to 475degC , becoming red hot, radiating outward into the outer shell, increasing the temperature of the outer shell, thus increasing the outer shell's radiance back to the inner ball. Describe what happens to the temperature of the inner ball based on the returned radiance from the outer shell. What science governs this "thermal feedback"? I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 13-08-2019 05:06 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote:btw ... you did what I asked in considering warmizombie arguments for Global Warming Yes thank you for keeping this on tack. I almost have this solid in my head. So here is the thing: I know that in conduction you can have the temperature even out, regardless of the masses or shapes of things the temperature disparity results in "Heat" so thermal energy will flow from the higher temp to the lower temp eventually getting evenly distributed. What I was having trouble with is seeing how radiance would work the same way. So I did this diagram first and got confused: ----10---->Wall........Ball ........<-5--Wall--5->Ball ........<-5--Wall<-5--Ball I looked at that and thought, OK the wall takes in 10 and emitts 10, 5 in each direction, but the wall hands back 5. Meanwhile the Ball only got 5 I just stupidly forgot that just as the wall has two sides so would the ball. ----10---->Wall........Ball........Wall<----10---- ........<-5--Wall--5->Ball<-5--Wall--5->........ ........<-5--Wall<-5--Ball--5->Wall--5->........ So the the left wall has 10 in and 10 out, the right wall does, and so does the ball, 10 in and 10 out (5 from each side). So just to solidify this: Radiance is going to just flow around just like conducted thermal energy. If it theoretically has no escape (or the supply is kept level) than all of the matter OF THE SAME EMMISSIVITY would get to the same temperature correct? Objects would radiate with the same intensity as the radiation coming in from nearby. Would you have different temps in the emmissivities were different? |
| 13-08-2019 05:52 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote: So here is the thing: I know that in conduction you can have the temperature even out, regardless of the masses or shapes of things the temperature disparity results in "Heat" so thermal energy will flow from the higher temp to the lower temp eventually getting evenly distributed. What I was having trouble with is seeing how radiance would work the same way. Yes, for the most part it works the same way. In our case there is no conduction of concern. All we have at play is thermal radiation governed by Stefan-Boltzmann (and Planck's). tmiddles wrote: So just to solidify this: Radiance is going to just flow around just like conducted thermal energy. If it theoretically has no escape (or the supply is kept level) than all of the matter OF THE SAME EMMISSIVITY would get to the same temperature correct? All of the matter of the same absorptivity signature, which is the case in our example, will reach the same equilibrium temperature of 80degC. . I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 13-08-2019 06:17 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote: oops forgot again it's the absorptivity that matters here. Couple questions: Does conduction always bring objects to the same temperature eventually, regardless of how conductive they are? An object in our field as described with a different absorptivity signature in the radiance wavelengths of 80C would likely have a different temperature? In this case the ball+Shell would behave no differently than if there was conductive material filling in the gap? |
| 15-08-2019 02:47 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote: oops forgot again it's the absorptivity that matters here. Couple questions: Does conduction always bring objects to the same temperature eventually, regardless of how conductive they are? An object in our field as described with a different absorptivity signature in the radiance wavelengths of 80C would likely have a different temperature? In this case the ball+Shell would behave no differently than if there was conductive material filling in the gap? Bump |
| 15-08-2019 02:58 | |
| James___★★★★★ (5513) |
tmiddles wrote:IBdaMann wrote: I can't believe you're asking notdamann a question like that. Aluminum is very difficult to weld because it can't absorb heat like steel can. Platinum-Alumnide is used to coat rotors in a gas turbine because of it's ability to reflect heat. The Stefan-Boltzmann constant really has nothing to do with global warming or the lack there of. Gravity generates heat and violates the 2nd law of thermal dynamics. |
| 15-08-2019 03:33 | |
| IBdaMann★★★★★ (14389) |
tmiddles wrote:Does conduction always bring objects to the same temperature eventually, regardless of how conductive they are? Yes. Thermal energy always flows from higher temperature to lower temperature. Remember what Into the Night repeats periodically: nothing can trap heat. Thermal energy will flow until the bodies are of the same temperature, at which point the 2nd law of thermodynamics tells us that there can be no flow of energy between them. At that point, the two bodies just radiate per Stefan-Boltzmann. tmiddles wrote: An object in our field as described with a different absorptivity signature in the radiance wavelengths of 80C would likely have a different temperature? I'm trying to remember the question I asked you. I believe that I was asking if bodies of different emissivities but same temperature could also have the same radiance. The answer, of course, is "no." Stefan-Boltzmann answers that question. tmiddles wrote: In this case the ball+Shell would behave no differently than if there was conductive material filling in the gap? Overall, yes, but the shell+ball+filling will take longer to reach the equilibrium temperature and if the IR field is then deactivated, i.e. drops to zero power, will drop more slowly in temperature, i.e. will always have a higher temperature, and will thus always have a higher radiance, all because it has more matter with more thermal energy at point of equilibrium temperature. . I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 15-08-2019 03:50 | |
| IBdaMann★★★★★ (14389) |
James___ wrote: I can't believe you're asking notdamann a question like that. You have a point. We'd all benefit from your response as well. Please, do tell. James___ wrote: Aluminum is very difficult to weld because it can't absorb heat like steel can. Unfortunately you are once again using the word "heat" to disguise the fact that you don't know what you're talking about. From The Manual: Heat: noun In the Global Warming theology, "heat" means whatever it needs to mean at any given moment. The term is employed by Global Warming believers to shift semantic goalposts as necessary. It's meaning can shift fluidly between "temperature," "increase in temperature," "thermal energy," "flow of thermal energy," "convection," "absorption of electromagnetic radiation," "energy," "conduction," "infrared," "plasma," "work," "power," "radioactivity," "electrical energy" and others as convenient. Aluminum's (or "aluminium's" for you Brits) welding issues stem from inconvenient melting temperatures, one for the aluminum/aluminium and one for the oxide layer ... not from its absorptivity at a particular wavelength. James___ wrote: Platinum-Alumnide is used to coat rotors in a gas turbine because of it's ability to reflect heat. I don't think i can [define it]. I just kind of get a feel for the phrase. - keepit A Spaghetti strainer with the faucet running, retains water- tmiddles Clouds don't trap heat. Clouds block cold. - Spongy Iris Printing dollars to pay debt doesn't increase the number of dollars. - keepit If Venus were a black body it would have a much much lower temperature than what we found there.- tmiddles Ah the "Valid Data" myth of ITN/IBD. - tmiddles Ceist - I couldn't agree with you more. But when money and religion are involved, and there are people who value them above all else, then the lies begin. - trafn You are completely misunderstanding their use of the word "accumulation"! - Climate Scientist. The Stefan-Boltzman equation doesn't come up with the correct temperature if greenhouse gases are not considered - Hank :*sigh* Not the "raw data" crap. - Leafsdude IB STILL hasn't explained what Planck's Law means. Just more hand waving that it applies to everything and more asserting that the greenhouse effect 'violates' it.- Ceist |
| 15-08-2019 03:53 | |
| tmiddles★★★★★ (3979) |
IBdaMann wrote: If the "filling" meant more mass I take it. All clear. So here's where I'm still at with shell vs open: tmiddles wrote: I do realize that this is a simplistic model above and that having more thermal energy would increase the rate/heat. But the model is just to check the basic way in which the thermal energy would move. I think this is just a model of insulation/reduced heat right? Edited on 15-08-2019 04:29 |
| 15-08-2019 04:42 | |
| James___★★★★★ (5513) |
IBdaMann wrote:James___ wrote: I can't believe you're asking notdamann a question like that. You and Isn't both accept that heat is a flow. And now you are rejecting your own statement. |
Join the debate Greenhouse Gases Do NOT Violate The Stefan-Boltzmann Law:
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