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E=mc^2 Verified In Quantum Chromodynamic Calculation
chirishnique and other readers sent in a story in AFP about a heroic supercomputer computation that has verified Einstein's most famous equation at the level of subatomic particles for the first time. "A brainpower consortium led by Laurent Lellouch of France's Centre for Theoretical Physics, using some of the world's mightiest supercomputers, have set down the calculations for estimating the mass of protons and neutrons, the particles at the nucleus of atoms. ... [T]he mass of gluons is zero and the mass of quarks is only five per cent. Where, therefore, is the missing 95 per cent? The answer, according to the study published in the US journal Science on Thursday, comes from the energy from the movements and interactions of quarks and gluons. ... [E]nergy and mass are equivalent, as Einstein proposed in his Special Theory of Relativity in 1905." Update: 11/21 15:50 GMT by
KD : New Scientist has a slightly more technical look at the accomplishment.
First = MC^2
Damn Frogs ... they are good .....
... no shit, sherlock.
Cowboy Neal isn't 'heavy set', he is just full of energy?
All that computing power to verify what Einstein figured out with his head and a chalkboard.
Trolling is a art,
Also on Yahoo, but with a horrible headline. Anyway both just reproduce the AFP text.
The original article seems to be this:
"Hannibal's plans never work right. They just work." Amy/A-Team
It's all relative
As per the title. Is there nothing on arXiv or something for those of us who don't think quarks are Ferengi bartenders?
So, we've now established that assuming we have a discrete four-dimensional universe, energy and mass are equivalent.
Now prove that this assumption is true, for the win.
"You fools! You've altered the outcome by observing it!" - Professor Hubert Farnsworth
As I understand it there were several geocentric models of the universe that were mathematically validated.
Am I mistaken or, doesn't that just mean that our theory matches all the known data and the data matches the theory. It Really doesn't have anything to do with whether or not the theory expresses reality.
âoeTolerance applies only to persons, but never to truth. Intolerance applies only to truth, but never to persons.
If mass translates to energy and energy being lossy, shouldn't the mass of nucleus decrease over time? :-)
Anyway, the article seems to indicate that the energy produced from the interaction between quarks and gluons account for the extra mass. What is to say that the energy produced from the interaction is always the same? If not always the same, it implies that the mass of neutron may vary over period of time!
Btw, the article doesn't care to summarize how the super-computers were used in the proof (except for that last quote in the article).
For all these years I thought it was E=mc^2. Now I find out it is E=2mc!
New Scientist has a slightly more technical look at the accomplishment.
When I read a sentence like that, I begin to wonder if maybe I'm getting my science news from the wrong source.
Since the missing mass is from the movement, does this mean anything in the search for dark matter?
"[T]he mass of gluons is zero and the mass of quarks is only five per cent. Where, therefore, is the missing 95 per cent? The answer, according to the study published in the US journal Science on Thursday, comes from the energy from the movements and interactions of quarks and gluons. "
To repeat what A.C. asked...
This is too obvious to be correct, but perhaps that explains "dark matter"???
(Or is this missing 95% already accounted for somewhere?)
Could someone please explain to me why photons don't have mass but do have energy (Photons)?
This does not prove anything about E=mc2. You can't "prove" fundamental equations by twiddling bits.
They ASSUME that E=mc2, then use that equation to calculate the details of nuclear energies.
In the article: "According to the conventional model of particle physics, protons and neutrons comprise smaller particles known as quarks, which in turn are bound by gluons." Shouldn't it read: "are comprised of"?
No, they're saying that 95% of the mass of the normal matter is in fact interaction energy between the subatomic particles.
So 5% or 5% is actually "stuff" :)
Yes. This 95% is the mass everybody expected to see in plain old ordinary matter, but wasn't previously accounted for in the QCD theory. We already had the experimental observation; now, we just know that the the theory gives the same answer.
Essentially, it's not telling us anything we didn't already know, so we don't get any new theories out of it. It does increase the confidence in the existing theory, so people who are trying to figure out what the dark matter is can rely more strongly on the theories we already have. But it's not opening up any new avenues.
It's always a little too bad when theory and observation do mesh, because it's when they disagree that we really learn something. But it's also nice to know that the theories are good ones, so at least we can use them as a basis for seeking out other discrepancies.
I could be totally wrong, but I was under the impression that all the 'missing mass' of subatomic particle was believed to be generated by the Higgs Boson/Field.
I TOLD YOU SO! Just kidding. Keep up the good work!
the correct statement is: E^2=m^2c^4 + p^2c^2
I thought the full equation was
E^2 = (mc^2)^2 + (pc)^2
It's about friggen' time.
Now for step 2? Resolving FTL Travel, Anti Gravity; and my personal favorite, Access to better Servers when I play WOW?
The article at theage.com gives a completely bogus interpretation, which is repeated in the slashdot article. The New Scientist article is much better.
This is just total scientific illiteracy. E=mc2 has been verified over and over again. We see it, for example, in processes like alpha decay, where the sum of the masses of the product nuclei doesn't equal the mass of the original nucleus. Mass is converted into energy in that process, and that's been experimentally established since probably the 1920's. Likewise energy can be converted into mass, as when cosmic rays hit the atmosphere and create electron-antielectron pairs. The theoretical foundations of E=mc2 are also extremely firm; it's deeply linked to the basic logical structure of relativity, and relativity has been abundantly experimentally verified.
Saying that this calculation verified E=mc2 is just stupid. The calculation assumes (1) special relativity, (2) quantum mechanics, (3) some technical stuff about how to make special relativity and quantum mechanics work together (generic ideas about quantum field theory), and (4) a bunch of very specific technical approximations needed in order to get an answer out of this particular flavor of quantum field theory (lattice QCD). The calculation has a bunch of adjustable parameters (quark masses, coupling constants). You play with the adjustable parameters and get a bunch of numbers out (neutron and proton masses, etc). If the number of adjustable parameters that goes in is m, and the number of experimentally testable numbers that pop out is n, then n-m is the number of degrees of freedom that verify whether the calculation is right. (For n=m, it would just be a complicated exercise in fitting the data, like putting two points on a graph and saying "look, it's a line!") I assume they calculated more than just the mass of the proton and neutron, because otherwise n=2 would be less than m. I assume the n-m degrees of freedom checked out fairly well, because they're calling it a success.
To see why this calculation can't really be interpreted as a test of E=mc2, you have to imagine what would have happened if it had turned out wrong. If it had disagreed with experiment, then we would conclude that some of the assumptions built into it were wrong. Let's look back at the assumptions 1-4 above. Well, 1 (special relativity) has been verified a zillion different ways since 1905 (or even as far back as the 19th century, the Michelson-Morley experiment, with hindsight). 2 (quantum mechanics) has likewise been verified a zillion different ways since the 1920's. 3, the general framework of quantum field theory, has some ugly spots, but it's been used to verify things like the magnetic moment of the electron to a dozen decimal places, so it's still on fairly firm ground. 4 is extremely shaky; it's only very recently that anyone has claimed to be able to calculate anything at all useful and realistic with QCD. So if it had failed, no physicist in the world would have interpreted it as evidence that assumption 1 (relativity) was wrong. They would have interpreted it as evidence that assumption 4 was wrong: the lattice QCD approximations weren't good enough, probably for very boring, technical reasons that would only be of interest to a specialist in lattice QCD.
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Wasn't he the pitcher in "Bull Durham" that hooked up with Susan Sarandon?
Oh wait, that was Ebby Calvin 'Nuke' LaLoosh; nevermind!
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
With a good theory it should say something like 'if it is correct you will observe X and not Y and not Z' for a REALLY good theory it will also say something like 'if it is wrong you will not see X but maybe Y and/or Z, and we dont understand Y and Z yet'
Without a good test it is just a theory. A good test should have positive tests and negative tests.
Take 'global warmming' both sides have a lot of theory but very little in the way of good tests that can prove it one way or the other. Then you dig into either side and it is a mish mash of bad science. We barely understand weather more than a day or two out how can we say if it is real one way or the other? That is bad science on both sides.
We know that e^(pi*i)=-1
and i=Sqrt(-1)
So, to prove that e=mc^2,
we substitute for e, and you get
(mc^2)^(pi*sqrt(-1))=-1 or
(mc^2)^(sqrt(-pi^2)=-1
mc Hammer only had 15 minutes of fame, so squaring that is 225 minutes
If you had a pie, and you squared it off, and I took it from you, and made it round again, you'd have the square root of a negative pie squared.
But this is pi, not pie, so we need to divide by e, which we know is 2.71828...
So 225^(1/2.71828)=-1
I know this worked yesterday... one moment....
Use Heim Mass Calculator to easily compute masses of proton, neutron, electron and a lot of other particles as well, with a great precision (relative errors less then 0.00001) when comparing with most precise laboratory measurements available. The only hardware you need is Java in your browser.
This algorithm is based on 50-year old equations of Burkhard Heim thanks to his beautiful theory. Notice that it include computation of neutrino mass which was found in recent years. When Heim was working on his theory almost all scientist were sure that neutrino is massless. The only input which this algorithm needs is a bunch of well known constants: h (Planck's Constant), G (Gravitational constant), vacuum permittivity and vacuum permeability.
Our current "mainstream" (hate this word) theory known as Standard Model is full of inconsistencies which are forcing scientists to constantly mumble about "dark mass" and "dark energy" stuff.
It remembers me about Enrico Fermi's comment "Beautiful theory, wrong universe". Does it apply here?
42
What if these guys actually discovered a glitch in the theory, a mode where the amount of energy out exceeded the amount going in, tantamount to a free energy source - and then falsified the result in order to use the glitch for profit? "Nothing here, everything's consistent, now go away."
Conspiracy theory rules. ;-)
Take 'global warmming' both sides have a lot of theory but very little in the way of good tests that can prove it one way or the other.
You can test it by observing that natural sources of warming don't agree with the magnitude, rate, or timing of the observed warming; and that human sources do. You can further observe, for instance, that an enhanced greenhouse effect will lead to stratospheric cooling as a result of heat being trapped lower in the troposphere, and we do observe that. There are further predictions which distinguish manmade warming from various types of natural warming, depending on the type of natural warming. For instance, warming from the atmosphere means the oceans warm from the top down, which is observed, and disagrees with theories that have the surface heat come from the oceans. The greenhouse effect also means that you get shifts in the diurnal and seasonal patterns of warming which disagree with the shifts predicted by solar-induced warming, because of the daily/seasonal patterns in sunlight shifts which do not occur for the greenhouse effect. And so on.
[/q]The Higgs field creates mass out of the quantum vacuum too, in the form of virtual Higgs bosons. So if the LHC confirms that the Higgs exists, it will mean all reality is virtual. http://www.newscientist.com/article/dn16095-its-confirmed-matter-is-merely-vacuum-fluctuations.html Good to know that my pain isnt real!
"There are 11 kinds of people: those who know binary, those who don't, and those who could not care less!"
> Take 'global warmming' both sides have a lot of theory but very little in the way of good tests that can prove it one way or the other.
No, they don't. One side has a vast array of scientists who all draw the same conclusions from peer-reviewed research with near universal accord. They also have a good deal of data to back up their theories.
The other side has a bunch of deliberately designed, mutually contradictory, un-peer-reviewed theories for the sole purpose of making non-climate-scientists believe that the science is bad on both sides.
It's deliberately designed to appeal to people who don't know the difference between climate and weather. It should be pretty clear that I can predict that it'll be colder in January than August (in the northern hemisphere) without being able to tell you it will rain tomorrow.
There is science on one side, and a deliberately anti-scientific campaign on the other. Science has uncertainty, quantified and part of the theory. The other side exploits that people don't understand how scientists deal with uncertainty to achieve a political, not scientific, goal.
It seems odd that scientists now claim that something (matter) is creating from fluctuations in the nothing (vacuum).
Previously, the audacity was only had by bankers creating value from no-documentation mortgage-backed securities.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
...that a supercomputer calculation could be heroic. What did it do, rescue the researchers from a raging bear and then calculate this for kicks?
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Did anyone else read the headline as "Emacs Verified In Quantum Chromodynamic Calculation" at first?
Got Apathy?
Actually they assume E^2=p^2c^2 + m^2c^4. The simplified version of the the equation, E=mc^2 is only valid for particles with zero momentum.
It is remarkable in the fact that all of the previous attempts to mix Quantum-"anything" with Relativity have pretty much spectacularly failed.
Well, except for the attempt in 1931 by Dirac that was spectacularly successful and united Special Relativity with Quantum mechanics giving rise to the field of particle physics. You can even quantized GR but you have to put an energy cut-off in to make it renormalizable. Since there is no justification for such a cut-off such models are regarded as seriously flawd so we have a problem with GR+quantum but not SR+quantum.
Shameless linking, I know. But someone had to say it.
Might want to read your own Wikipedia link about particle masses. See that table with the mass of the electron and such? See the errors listed? Being off by 102.5 standard deviations on the mass of the electron is NOT close. The proton, his BEST calculation, is "only" 94.5 standard deviations off.
There might be some interesting ideas in there, but it doesn't appear to be cutting edge. He wasn't the first to posit neutrinos with mass, either.
In a theory of everything that tries to explain things 100% in terms of fields, there is no mass and everything is accounted for in the energy of fields generated sub-atomic particles.
In the case of this experiment, the "color" lattice fields of QCD make up most of the field energy and account for most of what would normally be attributed to mass. Earlier compuatations of quark field energy were able to account for all but about 10% of the "mass-effects" in field energy, but didn't take into consideration virtual particles (quark/anti-quark pairs) created in the energy and interaction of the QCD lattice. Apparenty with this new more sophisticated computation, they got the mass-effects accounted for in quantum chromo lattice field energy down to 2% (the rest of the observed effects being accounted for a scalar mass value).
So basically the verified that most, but not allof the missing mass (~8%/10%) can be accounted for by quark/anti-quark virtual particles. Maybe higgs bosons and the higgs scalar field account for the rest of the effects that manifest themselves as mass, maybe not. Or maybe they just forgot about another particle and another non-scalar quantum field and there is no higgs, and no missing missing mass. Or maybe they made a math mistake. We don't know yet, but at least we are getting closer to accounting for things.
Okay, so here's my take on all of this.
First, here's a different spin on what E=mc^2 actually means. What it says is that if you want to measure the total internal energy of some object (i.e., the part that is independent of its kinetic energy), then all you have to do is measure its mass. This is actually a very remarkable fact because it says that you don't have to know anything about it's internal structure; instead, you only have to know one of two things: A) its weight in a gravitational field of known strength, or B) its acceleration in response to a known force. (The "equivalence principle" asserts that these two very different experiments actually measure the same quantity.) So in other words, you can take this "black box" and do an experiment on it that tells you its full internal energy.
Because of this, since we have done experiments of type (B) to measure the mass of the B_c meson (the particle of the article), we in principle already know its internal energy. However, in addition to knowing its mass, we also have a theory -- Quantum Chromodynamics -- that claims to tell us exactly what its internal structure is. One way to test this theory is be seeing whether the total energy it gives us of the particle is equal to what we measured via. its mass.
To see this in a different light, suppose that we were trying to figure out how much energy is in an oscillating spring, and the only measurement tool we had was the ability to weigh the spring very, very precisely. Then if we thought we had a theory for how much energy the oscillation contributes to the spring, one way could verify it would be by measuring the weight of the spring before and after we start it oscillating and checking whether the difference matches our independent calculation of what the energy should be based on our theory of how the oscillations work.
This is the spirit of what this calculation does. We know that the meson consists of two quarks, but like a spring there are all sorts of crazy oscillations going on that we are also trying to understand precisely. So given that we know the mass of the quarks, we can check to see if our theory of how much energy the "oscillations" contributed by the gluon field agrees with the mass of the meson (which is very roughly speaking, quarks + oscillations); of course, this alone doesn't tell us that Quantum Chromodynamics is the correct theory of nature, but if we didn't see agreement between the two calculations then we would have to re-think our theory.
The thing is, actually sitting down and calculating exactly what these oscillations contribute to the energy is very hard, which is why it has taken people so long to actually succeed in doing it. Now they have an answer: our theory does indeed predict the same quantity we see in nature, so in this respect it is not obviously wrong. :-)
Snarkiness is inversely proportional to wisdom because it emphasizes feeling right rather than being right.
It is articles like that one in The Age that help increase the ignorance of humans.
Or perhaps it is my ignorance of the way equations are written in the .com.au part of the world. And the maybe they use e instead of E.
But, reading "... the mass of quarks is only five per cent" without them telling us OF WHAT only makes my brain hurt more.
You can test it by observing that natural sources of warming don't agree with the magnitude, rate, or timing of the observed warming; and that human sources do.
Define "natural."
Your opening statement implies humans are not natural, an assumption difficult to accept.
Rather, it's general relativity that is difficult to meld with quantum mechanics, but there has been some headway. String theories are such a construction. The only problem is that we don't know which, if any, string theory is correct.
Let the pointless semantic nitpicking commence ...
Is there a way in which this could be interpreted to give relativistic mass to distant objects? To put it another way, with some creative thinking can this be applied to help account for the missing mass of the universe as we "see" it? The result essentially implicates virtual particles as the source of most of the local mass we see, and I'm missing enough theoretical physics to figure out if this would create mass at relativistic distances as well. Any one know?
I find it rather funny that what you say is testable, actualy hasnt sucessfully been.
You seem to have a problem with logical relationships. An observation which disagrees with theory (A) does not support theory (B) just because it disagrees with (A).
For a theory to be successfull, it must make predictions. Thats all there is to it. Show me the predictions.
"His name was James Damore."
You're not even paying attention.
I gave a number of specific predictions of anthropogenic global warming which agree with observations, including the observed warming trend itself, stratospheric cooling, downward penetration of ocean heat, trends in diurnal and seasonal temperatures, etc. The predictions of all the competing natural warming theories disagree with observations for at least one and usually more than one of those tests.
"OK, the moment of truth is upon us! Come gather around (printer toner warms up, whirring away)...Let us all see the confirmation we've been looking for!"
(reads printout) "E=42 ?? Hey what the....Dammit Dave, have you been screwing around with the Infinite Improbability Generator again!?!"
You could make a frame of reference centered around any random religious shrine in Jerusalem, or around your neighborhood Taco Bell ...
- "History shows again and again how nature points out the folly of men" -- Blue Oyster Cult, 'Godzilla'
Let the pointless semantic nitpicking commence ...
Not at all. I seriously would like to know how you define it. In the absence of a less ambiguous definition, one is forced to conclude that your post belies a serious bias. That is, that there is a separation between nature and man. I'm not at all certain that any meaningful analysis of global warming (or any environmental issue) can be performed in the face of such bias.
I seriously would like to know how you define it.
I define it the way everybody else in the global warming debate defines it: "natural" changes are the ones that can't be directly attributed to human activity, specifically fossil fuel emissions and other anthropogenic alterations in atmospheric constituents, as well as land use changes and the like. Of course, attribution requires some theory, because we have to postulate a counterfactual, namely what the climate would have been like in the absence of this activity. And attribution has to include feedback effects (atmospheric warming which melts ice which changes the Earth's albedo and leads to more warming).
If you to make some pointless "but humans are part of nature" distinction, fine, but it's not advancing the discussion anywhere. The question of what climate changes can be attributed to, say, industrial fossil fuel emissions is independent of how you define the word "nature".
i'm one of the authors of the original paper (Christian Hoelbling) and unfortunately the AFP press release has seriously misquoted another press release and the end result is horribly misleading. we did *NOT* set out to proove E=mc^2 and we did not corroborate it any further than it already is.
what we did was calculating the mass of the proton and other elementary particles from the underlying theory with controlled systematic errors, no more, no less.
E=mc^2 is a prediction of SPECIAL relativity, which has (modulo a LOT of math) been shown to work well with quantum mechanics. Early examples: Klein-Gordon Eqn, Dirac Eqn. Later: Quantum Electrodynamics, and recently QCD. QCD is inherently Lorentz invariant and so should respect all the rules of SR. What is being shown here is that lattice based QCD actually gives the right numbers for the inclusion of vacuum fluctuations in the masses of fundamental particles (disclaimer - my field is gravity not QCD).
Quantum Mechanics and GENRAL relativity don't mesh well. In fact they lead to all kinds of infinities. The Bad kind. The ones we can't sweep under the rug.... ^W^W^W^W 'renormalize'. There are various efforts to make a consistent formulation (String, Loops, Dynamic triangulations, graphs, insert-your-favourite-that-I-forgot-here) but this is where the problem lies. GR and QM are not good together. But SR and QM is a match made in heaven.
Here is the abstract:
http://www.sciencemag.org/cgi/content/abstract/322/5905/1224
-------------------
More than 99% of the mass of the visible universe is made up of protons and neutrons. Both particles are much heavier than their quark and gluon constituents, and the Standard Model of particle physics should explain this difference. We present a full ab initio calculation of the masses of protons, neutrons, and other light hadrons, using lattice quantum chromodynamics. Pion masses down to 190 megaâ"electron volts are used to extrapolate to the physical point, with lattice sizes of approximately four times the inverse pion mass. Three lattice spacings are used for a continuum extrapolation. Our results completely agree with experimental observations and represent a quantitative confirmation of this aspect of the Standard Model with fully controlled uncertainties.
-------------------
Pion-masses of 190MeV.
So here is a some explanation: the pion has a mass of 139MeV, lattice simulations get (*a lot*) more expansive when the pion gets lighter. Most simulations are done at 500MeV and more. It is impressive that the got down that much, OK. But it is still some way to go (m_pi^2 is the relevant number).
Another approximation which is convenient: dont take anti-quarks into account. Nobody knows if that is a reasonable approximation or not, but it saves you about a factor of 100 in CPU time. I would assume that they used this "quenched" approximation.
So what did we learn from all that: a lattice calculation with several approximations gives a result which is not in obvious conflict with reality. E=mc^2 has very little to do with all that -- that is just how you sell these results to get more funding.
Nice that they are on their way, but since lattice calculations need CPU-time like m_pi^-6 or so we need another factor of 8 in CPU-time tims a factor 100 from the anti-particles; roughly 1000 or 20 years according to Moore. Good luck!
Stop spreading this ****, in the correct frame of reference newtonian mechanics is correct (unfortunately the frame of reference isn't much use as all objects are stationary (relative to each other))Also E=mc^2 isn't derived from any thought experiment and is in fact wrong for any non-stationary object, E=mc^2 simply drops out as the first term in E when you expand the Lorentz transformation.E = mc^2 [ 1 + 1/2 (v/c)^2 + 3/8 (v/c)^4....]v is the objects relative velocity to you
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Oh, hey, and another thing, Meat. You don't know shit, all right?
Sig this!
Both the title and the summary of the article are misleading, this article describes much better, what the scientist really wanted to acomplish.
It basically says, that the QCD is describing the gluon-gluon and gluon-quark interactions and therefore the electrostrong force correctly. This leads to correct proton and neutron masses.
Most of the computations were conducted with this computer.
One of my favourite scientific cartoons:
Einstein is standing at a blackboard.
He has written a formula, and then crossed it out: e = ma^2
He has written another formula, and then crossed it out too: e = mb^2
And now he is staring at the blackboard and scratching his head puzzled.
I am anarch of all I survey.
No! It is still wrong because relativistic mass is not a valid concept much like the sun orbiting the Earth is not a valid concept. Yes, you can construct a model where it seems to work for some things but fundamentally it is very, very wrong.
For "relativistic mass" to be true you would need, for example, the binding energy of the quarks in a proton to change when its moving fast...which would be in direct violation of one of the postulates of relativity: "the laws of physics are the same in all inertial frames". Einstein himself used to correct people against using a varying mass. Yes, I know it can be tempting and there are several undergrad physics textbooks out there that use it but that should know better. However at a fundamental level mass is an Lorentz invariant quantity and does not change when transforming between frames. Just like epicycles relativistic mass may work in some, limited, circumstances but it is built on a wrong concept.
You don't seem to know what a prediction is then.
A scientific theory comes with a method of predicting future observations. Please explain a method "The Theory of AGW" uses to predict a future observation (ie: an equation), and then we can examine its skill at predicting it.
This is a critical step in science.. it is not the same as "agrees with observations", it must agree with FUTURE observations. There are an infinite number of equations that can fit any finite set of past observations. The only evidence thre can be that you have an equation that shows skill, is predicting data that was unavailabe during its formulation, with each future observation eliminating more and more of those equations that fit past observations.
Survive the cut. Make a prediction. Then we'll talk.
"His name was James Damore."
You don't seem to know what a prediction is then.
No, you don't. But it's really funny watching you lecture a scientist on what science is.
A prediction can be made about any observation which wasn't used in making the prediction. It doesn't matter whether the data was taken before or after the prediction was made, as long as the prediction doesn't use that data.
Please explain a method "The Theory of AGW" uses to predict a future observation (ie: an equation), and then we can examine its skill at predicting it.
You use a climate model, ranging from a simple energy balance equation to a GCM fluid dynamic simulation.
These models have only existed for a couple decades, so it's hard to test their skill on future data, especially since it takes a couple decades for a climate trend to rise above the noise in the system. But for one example, see here. They find agreement of modeled and observed temperatures but disagreement with sea level rises, probably due to the fact that none of the IPCC TAR models had ice sheet mechanics (just thermodynamics). You can also look up the 1988 projections for Hansen's GISS Model II.
P.S.: There is no "The Theory of AGW'. There are a variety of related theories, each represented by a different model.
There are an infinite number of equations that can fit any finite set of past observations.
You're concerned with overfitting vs. generalization. As I said, this is not a problem if you're not actually tuning the prediction to the past observations. GCMs aren't tuned to, say, the observational surface temperature time series, or stratospheric cooling trends, or the diurnal temperature trend. They are tuned to some things, e.g., the Earth's observed radiation balance at the top of atmosphere, and then they are asked to predict other things they weren't tuned to, like global temperature, precipitation, ocean heat, and ice trends.
The only evidence there can be that you have an equation that shows skill, is predicting data that was unavailabe during its formulation,
Yes, exactly. Which is why you withhold data from the model when it makes its prediction, and test it against the withheld data. That's how cross validation works. Certainly it's nice to have the luxury to be able to compare against future observations, but that's difficult when the system response is slow and noisy. It is incorrect, however, to claim only forecast skill is an indicator of predictive skill. Hindcast skill is an indicator as well, as long as you predict and validate with separate data sets.
You said "Blah blah blah" and you are wrong.
The problem with your vision of prediction is that *many* climate scientist search for such basardized "predictions" as you call them. This is data-mining 101. They are equation mining for methods, given existing data set A, which can fill in values of data set B. If they do not fill in those values, they do not publish.try a new set of equations, until finally they can publish.
Your utopian view of what is occuring is false. The real thing happening is that there are a thousand-and-one climate scientists fishing for funding, permuting through methodologies, until they can get published. If the filter on the publishing side is that it must show skill at filling in a given data set, then thats exactly what you get. It *IS* fitting to the existing data.
In the financial world, claims of the validty of a prediction mechanism based on the standards of climate science, would get you THROWN IN JAIL. Why do you suppose that is? It is because you cannot tell the difference between fitted methods and predictive methods until real predictions are made.
"His name was James Damore."
The problem with your vision of prediction is that *many* climate scientist search for such basardized "predictions" as you call them. This is data-mining 101. They are equation mining for methods, given existing data set A, which can fill in values of data set B.
Lying about their methods does not support your position. I described to you how GCMs are calibrated. If you refuse to pay attention, this is not an indictment of their methods.
Your utopian view of what is occuring is false.
Considering I actually know some climate modelers, and I doubt you do, I'm afraid this is not a compelling argument.
Dude, when all you've got is conspiracy theory, you've lost the argument. It's just an excuse for you to dismiss arbitrarily large amounts of evidence. No matter how much study or data there is, you can simply wave it all away as biased, without any actual scientific evidence to support your conclusion.
It is because you cannot tell the difference between fitted methods and predictive methods until real predictions are made.
This is manifestly false, as I already explained.