Except the wiggliness does change because the atoms emit infrared radiation as a result of their changing electric dipole moment. So they do lose energy. Feynman is wrong.

There is still no loss of energy.

The atoms lose energy. Total energy is constant, but some of the atoms kinetic energy is converted to radiation.

He is also wrong because he didn't go into a thorough discussion of convection, and heat "gained" through the fission.

What he got completely wrong is the heat "lost" to the coffee-cup system due to cups of coffee being consumed as a beverage.

Yeah right Feynman who has a great book written on Statistical Mechanics "failed" to notice equipartition theorem, vibrational rotational motion and dipoles and the entire topic of thermal radiation emission, KT per degree of freedom at equilibrium etc . Come on now! Non equilibrium thermodynamics anyone? That probably started from the atoms dont lose energy bad expression. Obviously atoms have kinetic energy and when they collide/"scatter" with other atoms of the same or even of other material, whether you do it classically or Quantum mechanically, their kinetic energy can potentially change.

http://en.wikipedia.org/wiki/Thermal_radiation

"Thermal radiation is electromagnetic radiation generated by the thermal motion of charged particles in matter. All matter with a temperature greater than absolute zero emits thermal radiation. When the temperature of the body is greater than absolute zero, interatomic collisions cause the kinetic energy of the atoms or molecules to change. This results in charge-acceleration and/or dipole oscillation which produces electromagnetic radiation, and the wide spectrum of radiation reflects the wide spectrum of energies and accelerations that occur even at a single temperature."

"Infrared energy is emitted or absorbed by molecules when they change their rotational-vibrational movements. Infrared energy elicits vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states for molecules of the proper symmetry"

Also http://en.wikipedia.org/wiki/Infrared_spectroscopy.

http://en.wikipedia.org/wiki/Equipartition_theorem

"The law of equipartition breaks down when the thermal energy kBT is significantly smaller than the spacing between energy levels. Equipartition no longer holds because it is a poor approximation to assume that the energy levels form a smooth continuum, which is required in the derivations of the equipartition theorem above.[5][9] Historically, the failures of the classical equipartition theorem to explain specific heats and blackbody radiation were critical in showing the need for a new theory of matter and radiation, namely, quantum mechanics and quantum field theory."

Not that I thoroughly understand these explanations, but I take it I wasn't wrong to question his explanation in the video. At least I got that part right.

That's correct. You were right, Feynman was wrong. 100% completely and utterly wrong. And it makes no difference what he knows or how many books on statistical mechanics he wrote. All that means is that he should have known better than to make such a statement. He would have been more correct to state just the opposite of what he stated, that atoms lose energy over time just as the rubber ball does unless that energy is replaced from outside. At least Tyson's errors are confined to history while he gets the science basically right.

Lestat hears this all the time.

Wanna bet $100 that Feynman didnt say anything wrong in that video?

You wanna go for it?

Care to view the video again and then for example read this trivial link;

http://en.wikipedia.org/wiki/Elastic_collision

and pay attention to his words speaking about "atoms" not an atom.


The guy anyway goes on seconds later to describe what is happening that can never be interpreted as not eventually losing, as a group of say the ball atoms, energy to the ground atoms (or molecules whatever material). So why the happiness to attack the guy that gave us QED ie the very theory one can use to describe how the radiation is emitted by atoms or molecules in their interactions. Its kind of ridiculous dont you think to entertain the idea that even anything that could qualify as error is not usually a badly worded linguistically sentence (and probably not even that here) rather than wrong fundamental idea? (not saying that the good guys avoid errors and sometimes even deep conceptual ones, but usually its something else and they deserve as many breaks to offer them as possible because its childish to think otherwise especially when there is plenty of related material to counter the notion of error in that direction)

I originally thought also the expression was wrong because its easy to consider the analogy ball/atom, but he spoke of atoms as a group not losing energy in their collisions because of perfect elasticity (the collisions are indeed elastic but only for atoms) (ie consider internal degrees of freedom require you know what ...molecules ie bonds etc). There is no electric dipole moment (of serious size) in atoms. They have only the 3 degrees of freedom from translational motion (kinetic energies sum conserved= elastic) unlike the polyatomic molecules that have extra degrees making their collision potentially not elastic.


http://arxiv.org/pdf/1112.4595.pdf

http://www.sciencedirect.com/science...31916365905834

Schiff Physical Review 132 (1963) pg 2194 (ie Schiff screening)

http://user.physics.unc.edu/~engelj/papers/le.pdf

Of course he didn't.

I'm hoping that it was obvious what I was doing when I said something about Feynman not mentioning anything about someone drinking the coffee.

What Bruce is doing doesn't even amount to being a correct nit at the level of Planck's Constant sized nittiness.

One still of course need to consider to be thorough emission of infrared radiation while atoms interact with each other, their electrons may be affected and of course in a photon bath the overall black body radiation equilibrium absorption/emission etc changing the overall thermal energy energy of the atom ie without transitions of the electrons in different orbits.

(so i suppose you can imagine what he was talking as similar to http://en.wikipedia.org/wiki/Rutherford_backscattering.)

See also things like; http://en.wikipedia.org/wiki/Spontaneous_emission
http://books.google.com/books?id=J_0...ion%22&f=false

Dont forget the surface of the coffee and the cup are also radiating thermal photons so you need to keep those enclosed too. But i suppose the time scale of radiation loss and the vast number of collisions/interactions dominate the effect here (vs photons emitted). Plus coffee has molecules not atoms so its easier to not have elastic collisions anyway there plus its not gas. Lets just say that the example offered to a crude audience was given with coffee for making a real life connection but then for simplicity it went to atoms etc failing to remain consistent but it never arrived at the level of some profound mistake. The guy knew what he was talking about and if anyone wanted to pi$$ him off a bit with polemic attitude he would invite them to the board to do some QED calculations and never even fail to remain calm and smiling all the way to transition amplitudes adding another chapter to a future edition of his book for the hell of it. Some people should die at 150 if at all lol...

If anyone wanted to be outnitting the nits here they only have to mention that at the start of the sentence he says imagine...HEHE! (one can imagine all kinds of things lol)

Of course I'll bet because he was clearly wrong, and I can't believe we're even having a debate about it. Read the caption in your own link where it says

"As long as black-body radiation doesn't escape a system, atoms in thermal agitation undergo essentially elastic collisions."

That black body radiation is the infrared radiation I was talking about. It's even worse than the bouncing ball because they radiate all the time, not just when they are colliding. He was talking about coffee which is mostly water whose atoms are bound in molecules which are highly polar and undergo inelastic collisions. He certainly wasn't talking about a gas of individual atoms. But even atoms and elementary particles have electric and magnetic dipole moments, and their collision will disturb these fields and create EM.


It's not a matter of happy or unhappy. It's a matter of right and wrong, and he was wrong. What's ridiculous is you bending over backwards to defend a wrong statement just because it was made by your hero, even after every link you've posted makes the same point I'm making. In science, unlike other fields, you're right or you're wrong based on the science, not because of who you are. Or at least that's the myth.

So I ask you a simple yes no question. Do the atoms atoms in coffee maintain exactly the same energy before their collisions as after, or do they not? If not, then send me my damn check already.


Or bitcoins even.


Oh stufu, you have no idea what you're even talking about. Let me fit you with some night vision goggles and hold you face in front of a hot coffee cup, and you tell me how nitty I'm being. I'm not being nitty at all, I describing a very large and fundamental effect. The molecules in coffee radiate like radio transmitters. If you think that is anything like the "fission" going on in your coffee cup, then you simply have no concept of the relative importance of the effects involved. Or did you confuse "fission" with "diffusion"? If so, I suggest you get that straight before you alarm your customers with talk of fission. And btw, a great deal of thermal heat loss through windows is radiation of the sort I'm talking about. Your initial comment about heat energy not being lost was incorrect as it is lost to radiation. So hush, the adults are trying to have a conversation.

So there's a lot going on in the reality, and this is what Bruce and Masque are going back and forth about.

In the purely classical model that Feynman is imagining, the dissipation process happens through collisions. If you have a room with a cup of coffee in it, and air in the room moving about randomly (at some temperature cooler than the room), given enough time, each atom will eventually be bumped, and all the air in the room will be jiggling faster than when everything first started. the total amount of jiggling (energy) in the entire room remains constant, but not the energy of any particular atom. The cup of coffee will have cooled off and transferred all of the lost energy into the air in the room (which are now jiggling a tiny bit faster than at the beginning).

Reality is more complicated, as energy can be transferred in ways other than bumping into each other. The energy we are getting from the sun does not come from the jiggling of a line of atoms from here to the sun. Hot things shoot out photons. Photons have an amount of jiggling, and that counts towards the total energy count, too. This is the black body radiation that BruceZ is talking about.

The law of conservation of energy says that for any closed system, the amount of energy in the entire system will remain constant. So if the universe is a closed system that was created by the big bang, then all the energy that was in the universe then is still in the universe now.

Yes but i already talked about all these issues and you still didnt take back the dipole electric moment thing that atoms dont have, nowhere near as the molecules, and they do not have these extra degrees of freedom that energy can go in collisions to make it not elastic. And the guy is talking atoms. I also said coffee is not atoms. So in coffee you will have a lot of things going on but he said atoms, end of story.

Now in going to atoms, you have thermal radiation but at the same time you have huge number of collisions per second eg if we take a gas, its different but still plenty collisions in a liquid too. Many different degrees of freedom too. So it has to be some monatomic liquid then.

In any case the only question left to see is what happens when atoms not molecules interact and how infrared radiation relates to it all. I maintain that the collisions per sec are much more than the photons emitted by some surface. We need a thorough analysis of a scattering process between atoms to see if there is significant radiation because of the scattering and the effect on electrons.

I am essentially claiming that in a per interaction event the collision between atoms is nearly elastic as claimed and the overall kinetic energy change is tiny on the system of the 2 something not true for molecules.


I will look further into it to see a proper calculation for just atomic systems. We could consider examples though and calculate collision events per sec and compare it with photons emitted per second.

I do not see how you can possibly claim though that the guy didnt know what is happening after a lifetime playing with such systems. He was speaking in very simple terms and the remaining seconds were spent to show exactly how energy is transferred from one to the other.

I invite you to consider a cup with hot water and see how much of the energy of the hot water is transferred to the cup in 10 seconds vs the thermal radiation emitted from its top surface and i bet you will see a big difference in numbers (plus we really need a liquid that has atoms ). Basically a cup liquid surface at near 100C radiates like 10 W thing but is almost instantaneously heating the cup to beyond ability to hold it (so massively more than 10W there). So you figure out how much then the molecules in that case lose to radiation per collision for this to be true.

Its not about bending backwards etc for a hero. Atoms do not have electric dipole moments as large (negligible basically) as molecules do. See the linked Shiff 1963 theorem. Its about respecting the intellect of a person that has proved it over and over before and not trying to see the worse possible interpretations in what they say when they speak to ignorant public anyway.

Lets use this as an opportunity to study the microscopic theory of thermal radiation emission in systems of both atoms and molecules of a given temperature.

No, he was talking about coffee, and he said that we have to imagine that the atoms are "perfectly elastic", and that unlike the bouncing ball they "never lose energy". That's wrong for coffee which is comprised of polar molecules that collide inelastically. If you want to claim he was suddenly talking about something monoatomic that he never defined, then he's still wrong because of thermal radiation which is produced when the colliding atoms change their rotational and vibrational modes as your own link said. If a photon is produced in the collision, then that collision isn't elastic by definition. I don't have to take anything back. Just because an atom doesn't have an electric dipole moment in its ground state doesn't mean it doesn't radiate. It produces thermal radiation, it has a magnetic dipole moment, and it can take on an electric dipole moment during collision.


And the cup better also be made of something monoatomic too, otherwise what he's wrong again, and the collisions with it will be inelastic just like the bouncing ball.


The claim was perfectly elastic, not nearly elastic. I have no idea what nearly elastic means. A super ball is pretty elastic, that what you mean? I do know what "perfectly elastic never loses any energy means", and that's what he claimed.


I didn't say he didn't know what is happening. I said that what he said is wrong.

He was talking about a ball bouncing that loses energy at super fast rates like eg tennis or basket ball. The atoms are nowhere near at that rate and thats all he meant. Otherwise be my guest and calculate the rate of thermal emission per collision and see how tiny it is but i already gave you the argument with a hot cup of water that instantly makes you want to drop it and thats not the work of some tiny 10W Stefan Boltzmann type thing. Next thing lets calculate also gravitational radiation and the differential cross section with respect to neutrino radiation background.

can not believe some of you guys in this thread. Neil deGrasse Tyson seems like a really down to earth guy and actually has a personality. this is a an interview of him recently where he went out of his way to attend a amateur charity wrestling event. how can you say this guy is pompous? unreal.

http://www.flowrestling.org/coverage...cause-Its-Hard

Science absolutely needs cheerleaders; in fact, I'd go so far as to say we have too many scientists and not enough scientific cheerleaders. Note that when I say "cheerleaders" I mean it in the sense of "communicator" not of "advocate for a specific policy or action based on science."

Every AAAS fellow and NAS member I've ever met has been a pompous ass, btw. N=20ish.

Lets just say that maybe Sagan was a bit better. David Attenborough's or James Burke's style is better. Also people like Feynman's style in interviews are so charmingly confident and yet at the same time unafraid to risk and appear as if they dont have all the answers and its not about elevating themselves always above others as center of importance in interviews and debates. There are others that are nice too like Weinberg. I am sure Dirac/Fermi/Oppenheimer were great to talk to as well. Penrose is great. Chandrasekhar was great as well. I am talking personalities here as they appear in interviews/lectures and books/documentaries and how they connect with the audience in talks in ways that make you like their topics and still feel attracted to their style and humanity. Without being a scientist Morgan Freeman has a better feel in documentaries. What if Tyson was like that but unlike Freeman at least enjoying the deep understanding of the topics involved due to his astrophysics origin. By the way i have no issues with Cosmos in that regard, that promoting style is very slight there, almost no room for it due to content structure. Science needs promoting but requires also someone that inspires as a person to illuminate better the coolness of it all, not as a game of personal victory over others but as an adventure towards wisdom that proves a selfless gift to all mankind, still a tremendous arsenal for life to master at any respectable depth.

Yes the functions of a general figure that promotes science at large are different than that of a top specialized topics scientist that gives university lectures. And yet i can never escape how good/cool/inspiring the best lecturers i have witnessed in Math or Physics appear not with their promoting personal style but due to the richness and ingenuity of their examples and the friendly non patronizing approach. I think Sagan played that role very well. Tyson is doing a good job for young people with all these shows and exposure. I dont have a problem with the man. Its just that i think if he could tone down the pompous self promoting (almost like the original ancient greek world pomp= marching process) style and the occasional look down on others in interviews (Lawrence Krauss another popular science interviews figure suffers from that a bit too but escapes it with smaller loss). He doenst have to dominate all the discussions. Its not a contest, its a selfless with personal touch contribution to the audience, thats the style that strongly inspires. You could hear/read Einstein speak for ages and never feel tilted never feeling distant etc .

Tyson is not alone by the way. Tons of others are like that for sure in many countries. They can all learn a lot from Feynman. The ultimate cool is to be confident, happy, charming and not selfish at all, to be able to appear vulnerable and yet confident and friendly to all even those you disagree with.


When Feynman died in his blackboard one could read these brief notes to self suggesting how he was spending his time remaining a student of physics till the end (the ultimate anti pompous position);




I still stand by the position that science needs strong well thought promoters not cheerleaders. It needs i think those who achieve the promotion with their own personal example, creativity and inspiring friendly composition of ideas and interaction with others. It is a charisma thing once more. It has to be selfless.

The philistine's ratings rise on Easter Sunday

I was about to say the same thing, or 95%. I even remember taking philosophy and just getting a headache.

What is the nature of reality? Philosophical or scientific question? Both?

It started out as a philosophical question, which then piqued the interest of science. It still, however, is a philosophical question.

That's the result of thinking about things you're not used to thinking about.

Try asking the everyday person to think about a deep problem. They will typically give up after less than ten seconds of thought.

I agree with the article in the OP.
It's like Tyson is saying:

"Don't worry about history, philosophy and 'big' questions, dont think about them and don't think for yourself, let us do the thinking for you.
Even more so, we (the scientists) already did the thinking for you and already know the answers so just listen to what we are saying and trust us, we wouldn't lie to you, we are scientists ..."

If he's a messenger of science then he sure makes science look like just another religion.
Or a cult.

It's a religion and a cult, but that's OK because it's the one true religion and cult. Of course all the other religions and cults say they that too, so how are you to know who to believe? Well, that's a philosophical question, and in this cult we don't ask that.