BYIJ - OK, thanks. I've got a 3 inch cardboard tube a couple of feet long. Do you think that would be suitable? Maybe air at the bottom of the tube would do instead of water - I can bung the bottom end up with foam polystyrene, with alu foil (to stop radiation/heat getting in the bottom end of the tube.

And I've got an inside/outside £3.99 electronic thermometer with a probe on a wire which should do.

ssat
Question from curiosity, is this

You need a net pyrgeometer or net radiometer

the same point as is made by AlecM/MDGNN?other aliases? If so then that's QI.

ssat,

I don't finally admit anything. I have disproved your every argument,

You are deluded. You finally admitted that Body B warms Body A by IR radiation. It took me a long time to get you to admit it, and you may be in denial about the implications of that, but if you still think you 'disproved' back-radiation, then I wash my hands of you, and wish you well living in your little fantasy world.

Sandy S

QI.

Qué?

AlecM/MDGNN can speak for himself, I have not had any conversation with him. If he has stated that he might want to explain in what context. The instrument manufacturers explain its uses.

splitpin, I haven't done the experiment myself.

The reason I suggested water was that evaporation lends a hand.

3 inches seems a bit wide for the short length, but it's worth a go. Probably best to insulate the outside of the tube if possible (foil would probably do) - if you only insulate the bottom part around the thermometer, the cardboard tube might be not block enough IR to make a difference. Alternatively bury it, or pile up earth or sand around it, so only the hole remains open.

Let it sit for a while (hour or two?) before opening the hole, this is to make sure the thermometer settles down to ambient temperature.

No idea how long it'll take, or even if it'll work with such a short tube, but interesting all the same.

TBYJ

Warm: v.tr. To raise slightly in temperature.

You finally admitted that Body B warms Body A by IR radiation.

Cooler Body B raises slightly the temperature of the warmer body A? I rest my case.

ssat,

Cooler Body B raises slightly the temperature of the warmer body A? I rest my case.

You case was exactly the opposite. It must feel good to have disproven your own thesis.

BYIJ - thanks. 3" is diameter of tube. Tube is 2ft long. Won't attempt to do it tonight - better to think about it and prepare it carefully. But I can assure you it's cold out their this evening under a clear sky.

there

TBYJ

This is like arguing with a troll! It was you that stated that Body B warms Body A and were triumphal when you thought, incorrectly, that I agreed with that. I state that Body A cools more slowly in the presence of body B and have consistently done so, which you now acknowledge. Therefore, I do not see the point of your post or the logic of your last sentence.

ssat,

I was triumphal because once you admitted that Body B transferred heat energy to Body A via IR radiation, you were acknowledging the back-radiation effect. There is no difference in physics between making something warmer by supplying IR photons, and stopping something getting colder by supplying IR photons. It is IDENTICAL in physics, and is only a matter of magnitude. Once you admitted B supplies heat to A, you admitted back-radiation exists, which is great, because it does.

Now you may not see this, or see the implications of this. I reached the same point with RKS and Dung and many other people, and they too failed to make that brave intellectual final step. I can't put it down to stupidity, because you are not stupid. It's almost like a psychological hang-up, to admit in back-radiation means admitting AGW might be real, that the left political argument might have merit, that your whole life philosophy may have to be re-evaluated - and that is not to be countenanced. Who knows. That's just speculation.

All I know is seeing you follow the physics through to its logical conclusion, and then fail to make the final decisive step is both terrifying and tragic in equal measure, for me. I must lay some of the blame in my lack of explanatory powers, it can be no coincidence that I always fail at the same place.

But part of the blame must lie with you. To imagine that you (alone) have discovered a single huge flaw in modern science which generations of physicists and engineers have overlooked is breathtakingly arrogant. We do have the occasional massive intellect spring forth from the lay population, but I'm sorry ssat, you are not one of them.

I'm not trolling you. This is yet another massive failure for me, and it stings me deeply.

rhoda,

Is that how modelling works? It seems back to front; you define what the model must project and the task is to modify the code/parameters until it obliges.

Therein lies the entire debate.

They are different effects, but they are the same physical mechanism. The difference in effect is because one supplies enough photons to heat the body up, the other only supplies enough to stop it cooling down.

You hate analogies, so here's another :) This one is short and mega-simple though, and cuts to the chase
of this, so please bear with me.

An iron ball is rolling down a chute. At the bottom, I aim a gun up the chute and fire bullets up at the ball.
If I fire more than once a second, the force of the bullets sends the iron ball slowly back up the chute.
if I fire less than once a second, the ball still rolls down, albeit more slowly than before.

In one case the ball goes up, in the other the ball goes down.

The physical mechanism controlling the iron ball is identical in both cases, only the magnitude differs.
But the effects (up or down) can look radically different.

Switch 'temperature' for the ball's velocity. Switch 'IR photons' for the bullets.

Heating something up and preventing something cooling down is the same mechanism. It's the same cause.

And yes, I did paste the wrong quote in there :)

Jan 14, 2014 at 8:54 PM | TheBigYinJames

As rhoda keeps saying, what is your experiment to prove or refute your hypothesis? I like analogies but surely they are just a good lead into a decent experiment.

TBYJ 8:54 PM

1. An iron ball is rolling down a chute.

Energy = ball & gravity.

2. At the bottom, I aim a gun up the chute and fire bullets up at the ball.

Energy = bullets & explosions.

3. If I fire more than once a second, the force of the bullets sends the iron ball slowly back up the chute.

Energy of bullets & explosions is greater than energy of ball & gravity.

4. If I fire less than once a second, the ball still rolls down, albeit more slowly than before.

Energy of ball & gravity is greater than energy of bullets & explosions.

In one case the ball goes up, in the other the ball goes down.

In both cases, the flux direction of the net energy is from the higher to the lower energy state.
In neither case is the flux direction of the net energy from the lower to the higher energy state.
Energy transfer is proportional to the difference in energy levels.

Switch 'temperature' for the ball's velocity. Switch photons for bullets.

The higher the energy state, the higher the temperature. When the ball is descending its temperature is higher than that of the bullets. When the ball is ascending the bullets' temperature is higher than that of the ball.

Heating something up and preventing something cooling down is the same mechanism. It's the same cause.

Net energy flow from the hotter to the cooler.

ssat,

you ability to complicate an analogy astounds me. The ball analogy wasn't meant to be an analogy of actual temperature, it was to demonstrate that the same physical mechanism can cause an end effect to go up or down, which doesn't make each direction of the effect a 'different thing' as Rhoda was maintaining.

Net energy flow from the hotter to the cooler.

Net means difference.

Let's get back to the two bodies in space, A and B. A is hotter than B.

As you say, NET energy flow is ALWAYS from A to B. That's just plain physics.

But that doesn't mean B is not supplying energy to A as well.
All it means is the energy A is supplying to B IS MORE THAN the energy B is supplying to A.

That's what NET means.

B is still supplying energy to A. A has more energy than it otherwise would have if B wasn't there.

If you assume NET energy is the only energy that can do work, then I can see why you think A can only warm B, and not B warm A. This is because you misunderstand the nature of NET energy. In your scenario, Body A doesn't receive any energy because you've done an arithmetic subtraction of the two energy flows and said the NET energy is warming only Body B. You allocate energy ONLY to Body B. This is your mistake.

The reality is that the energy you subtracted from Body A's emissions (to get the NET that flows to Body B) resides in Body A, and keeps it warmer than it would be otherwise.

Please don't prove me wrong in my assertion about your stupidity.

Rob,

As rhoda keeps saying, what is your experiment to prove or refute your hypothesis?

This is not MY hypothesis, this is already proven physics. I'm explaining the current understanding, not proposing a new theory. If you want to read about the experiments which prove all these photo-electric and thermodynamic effects, then might I suggest my old undergraduate physics text "University Physics" by Sears and Zemansky (in my day Young was one of the authors) or any good standard Physics textbook. I don't need to repeat those experiments.

As I said much earlier... this is not NEW stuff, this is some of the OLDEST stuff in physics. It's not going to be wrong because someone stubborn on the internet says it is.

ssat
QI=Quite Interesting.

As you say he can speak for himself, although he does seem to work in what you might call "Mosher Mode" leaves one post which asks more questions than it answers or is more of a hindrance than a help.

I haven't read through all your latest conversations but it was the first time I'd seen anything posted here making the same/similar point as he does. As I say that in itself is quite interesting.

Thank you.

ssat
Now another question from curiousity we're (you're) basically talking CO2 and ignoring everything else? In that case wouldn't Mars be a good candidate for an experiment? There is no cloud or aerosols but some dust; as far as I can work out most of the parameters for measuring the effect are available and the atmosphere is 97% CO2, and 0.6% the mass of Earths. Therefore the CO2 is the equivalent of 0.58% in Earth's atmosphere in terms of mass so using well known (to some here at least) formulae and models the effect of CO2 should be measurable and be universal. The American Mars Rover should have sent enough data to at least get reasonably close answer, similar in proximity to Millikan's original value for the charge on an electron?

Let me know if I'm comparing apples with potatoes.

TBYJ

As I said much earlier... this is not NEW stuff, this is some of the OLDEST stuff in physics. It's not going to be wrong because someone stubborn on the internet says it is.

History would suggest that you're making quite a bold statement there, a caveat might be in order I think; arguments from authority, Einstein and all that.

ssat is not an Einstein.

Martin.

Yes.

But I also don't disagree with the way you have put ssat's point. With the small caveat that it's not exclusively from elsewhere.

Martin A

Yes, I'll keep it short.

Energy from 'back radiation' does not make things warm. They are warmed by energy from elsewhere.

When 'warm' is a verb, yes. I haven't said that but it follows logically.

Two objects at different temperatures exchange radiation, the net flow being from warmer object to the cooler.

It is I that have said that continually, illustrated it with Newton's Law of Cooling and still maintain it to be true.

Good luck with the grouting, I'll be doing some self-levelling cementing myself :)