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I never liked exile 3 much. It always felt more disorganized than the others (not related to the freedom to do stuff, just disorganized). Although I don't believe I ever played avernum 3? Or if I did, never past the demo area. I like the story of 6 from what I've seen, but as I've mentioned I don't like the gameplay much.

Yeah, but the confining force is also called the strong force. The yukawa / pion exchange force is a "residual strong force" interaction. This is one of those many exciting "you will know which one I mean by context" things in physics .

Yeah, radioactivation of other materials, and losing energy are problems, but I believe the radioactivated materials aren't nearly as radioactive as in a fission plant, and aren't active for nearly as long. So it's really a matter of just replacing parts that can't be too contaminated. So it's still better than a fission plant. But part of the science being done at these places is to determine how to construct materials that don't become contaminated, and if we can do fancy things like get energy back from the neutrons. From the people in ITER I've heard from, and from the experimental physics people I know who've talked about this, they are hardly not optimistic... They all seem to be very excited about it. And, really, we know very little about the engineering challenges we'd have to face anyway, which is the whole point of these science reactors. This is a regime where it's very difficult to do good theoretical calculations, and our collider experiments haven't necessarily dealt with. But it will certainly be a while before we can even think of making a commercial one... They've really just recently agreed on where to build ITER, and it won't be finished until ~2020, and there's at least a good 20 years of work that can be done there before moving on to the next generation of design.

Fission was never really dangerous. It's only dangerous when you're horrifyingly stupid with it (like with anything else). That's really what happened with Chernobyl, horrible incompetence, terrible design, combined with a collapsing economy. With fusion, we are at the stage where we do not get more energy out of the reaction than we put into it. Partly due to technology, and partly due to a lack of understanding of the details of how we should engineer this reaction to be self-sustaining. The new research reactors, e.g., ITER, and the other big one whose name I can't remember, I believe will be able to produce sustained power for short lengths of time. They should tell us how to design commercial reactors well enough that the next stage could be prototyping real commercial reactors. Solar is expensive to produce, and cannot produce nearly enough energy to be more than marginally helpful. It can be helpful in, very hot sunny areas where you can get constant extra bonus power, and on individual buildings where it can reduce the load on the grid on hot days due to air conditioning, which otherwise might cause brownouts.

Yeah, off the top of my head, those order of magnitude estimates look okay. But you don't need to replace 100% of energy production with solar energy. And I think part of the advantage is that you can get power to locations that you couldn't put normal powerplants, and running lines to would be too lossy. But in general, solar definitely isn't such a great solution for anything.

Originally Posted By: Randomizer Originally Posted By: Harsh Truths in Advertising —Alorael, who supposes that it might even be the preponderance of scientists that keep this place together. Okay, it's actually the strong force, but the physicists describe it best. No, the strong force only operates over the short distances within the nucleus. The strength of the force is inversely proportional to the operational distance. Gravity is needed to operate over the far flung distances between members or maybe electromagnetism because we are using the Internet. I'm still seeing Bart Simpson using static electricity to power his computer during a blackout. But the strong force increases linearly with distance! What else could hold things so tightly together? Well, unless you pull them too far apart then you get pair production... and unless you're in a quark gulon plasma, then there's Debye screening, of course... and then there's the jets and hardonization to worry about... Or maybe we're held together by the analog of the strong force for the case of N=4 SYM, which is like QCD but with no confinement? Yes, yes, that must be it... What were we talking about again?

I think attenuation of energy in the atmosphere is a big problem with these methods, no? Not to mention building a huge, efficient enough enough laser that requires no maintenance in space would be extremely technically difficult. Not to mention that people would complain that the REAL reason for building the space-lasers is for the government to use them as weapons, and to spy on your thoughts. OTOH, the government that can build space-lasers and doesn't is not a government that gets my support!

Saying chrono trigger is "just" an RPG is like saying Jesus was "just" a man to a Christian. Except Jesus can't cast luminaire or use triple techs. I actually think the absolute best thing Jeff could do in his new series of games is to take a page out of Valve's book (e.g., play through HL/Portal with commentary on, and note how much work they put into playtesting). I really think his games could benefit hugely from more broadly taking player's concerns into account (i.e., not just about the details and balancing), and doing the kind of usability testing that companies do. That is, *watch* a bunch of people play your game, see how they do things, see them get pissed at some things, or love some other things. As one of the commentary nodes in HL2 episode 2 said, "when our playtesters die while laughing, we know we've done a good job." And that's really true, because there are so many times I've been amused at how I'd died in HL2 or Portal. I very rarely got frustrated at HL2, and I don't think ever at all in portal. But there've been plenty of times I've had to quit Jeff's games because I got to some place that was just punishingly unfun. Not necessarily (though sometimes) hard--just unfun. Another thing they mention--"the player should never feel like the game mechanics killed them." But really, I feel like 75% of my deaths in Jeff's game are because of the game mechanics (the other 25% are from accidentally going to a place that's too hard for my level). Oops, my guy was one square too far away to be healed by mass-heal, he's dead. Oops, accidentally clicked behind the guy instead of on him because of the isometric view, now I'm dead. Oops, the game was too slow to respond and I accidentally clicked again sending one guy someplace I didn't mean and he died. Oops, pathfinding sucks and made my guy take a crazy path and use up all his AP now someone dies.... etc etc... In my experience trying to get other people to play these games, the mechanics is an absolute deal breaker, and has made every single casual gamer I've suggested Jeff's games to reject them as being too unfun. It's also resulted in me not having bought an Avernum since Avernum 3, and not actually played all the Geneforges. Which is really a shame, because other than the terrible mechanics and UI the games are fantastic. So I really think, plotwise, I don't care if the next game is linear, non-linear, faction based, or whatever, because I'm sure the plot will be great. But I really wish he'd be more careful with the gameplay mechanics.

Originally Posted By: CRISIS on INFINITE SLARTIES I swear that every time I make a Chrono Trigger reference here, fewer and fewer people get it. edit: Images don't work?! No! Spekkio is even less pleased!

One typically has to be very careful about the methodology of these kinds of reports to get any meaningful information out of them. Like Alorael mentioned, there are large uncertainties associated with oil reserves, since there're still large parts of the earth that haven't been carefully investigated for oil, and there has really been no incentive for oil companies to go looking for new places for a very long time. Also, the exact amount listed in various reports seems to give the "economically viable" sources, which changes substantially with technology and energy prices. So I'd be willing to bet based on this that, if we were pressed, we could get enough oil to last of order hundreds of years. Not so sure about coal, since I haven't looked into it. Nuclear fission also depends a lot on technology. With early fission designs, the available fissionable material would not have lasted nearly as long as with fancy modern designs. But certainly we've got enough to last in the thousands of years range. Fusion is basically something that can last forever, since the universe is full of hydrogen, and the solar system has got plenty in it without going too far. The biggest problem with fusion reactors is related to funding. No one really wants to dump a great deal of money into them right now, since the current designs are all (of necessity) geared to doing research as much as energy production. There are several experiments going on now that IIRC will be collecting data soon, but they've had plenty of funding and political problems to delay them. There also seems to be a lack of interest in the theory part of nuclear fusion, and the nuclear theory community in general doesn't seem to be what it once was, since a lot of the easy stuff has been done, and a lot of what remains is for technical reasons very difficult to do. But this problem again is largely due to funding, and the lack of funding has seemed to not attract the diversity of ideas needed to do super-clever things that allow you to solve new problems.

I think my favorite game is Exile 2. It's one of the only games that had more of a sense of exploration in it. You had a whole new unexplored area that you were the first human to see, outside areas seemed large (unlike the newer Avernums). I also like the old hidden wall system, it was always fun to find some hidden area in the side of a cave wall by carefully exploring (even if there wasn't much in it). I also liked the old magic system, even though for the most part you only used a small number of spells, there was always the possibility to do something more clever or tricky with one of the less common spells. The larger number of spells also made magic feel more real. The simplified graphics were also kind of nice, because they were simple enough that the stylized representation looked reasonable, but in the newer games the more realistic, but still "stylized" graphics can look a bit awkward sometimes. But in terms of the UI, I think the newer Avernums are much nicer. They're a lot easier to play in a lot of ways, UI related tasks are a lot more intuitive, and it plays a lot more smoothly in a lot of ways. I also like the new battle disciplines a lot, but wish there could be a magic equivalent of them, which would help a lot with the less diverse magic system compared to Exile. The biggest negative I think the newer Avernums have, though, is the lack of a sense of exploration compared to the Exile series. I always thought that was the most fun part. Now, there are smaller areas to explore, and I seem to be accosted my monsters a lot more frequently when I want to explore the details and atmosphere in some places.

That's hardly a "new line." It's what's been said all along. In all of my studying strings, I've read almost nothing on string theory's predictions about planck scale effects or quantum gravity at all. In fact, the whole point of string theory is that it provides more ways to understand things from field theory. It's hardly a solution in search of a problem, anymore than understanding field theory to work with the standard model is a solution in search of a problem! There are several string theorists who work in other communities using string theory to help understand their fields... there are whole textbooks about these kinds of things. And you don't really have to go outside your body of knowledge to to this anyway, since to learn string theory properly you would be exposed to most of it already. Most of the abstract stuff in string theory is based on understanding what the structure of strings, just like the 10s-80s was all about understanding the structure of quantum mechanics and field theories. In fact, people made the same kinds of claims as you're making when people like dirac were talking about QM in terms of Hilbert spaces .

Uhh, but string theory really isn't about plank scale physics any more than condensed matter is about relativistic particles? It uses tools where you have to know about those things, but those tools are still useful very far away from those limits. The point of string theory is that there's a great deal about the standard model and field theories in general that aren't well understood. And string theory provides easy answers to those things. I mean, the historical development of string theory really only had things like extra dimensions and tiny length scales as accidental consequences. String theory isn't used in hydrodynamic calculations at RHIC for nothing!

Originally Posted By: Student of Trinity Actually global average temperature is a very good thing to try to model and measure, even though it's hard to infer accurately from the data we have, and even though its implications for any particular local climatic variable may be complicated at best. That's true, no one says it's a bad thing to measure, it just doesn't mean what most people think it means. Quote: CO2 mixes throughout the atmosphere; that's why all this human-driven-warming stuff started with measurements of CO2 levels in Antarctica, where there aren't very many power plants or cars. So the whole issue is looking for long term, planetary scale trends, in a system with huge local and short-term fluctuations. That's not easy, but it's the job at hand. But it doesn't mix uniformly through the atmosphere, it's only true to "first order" in some sense. There are lots of active and passive ways CO2 is interacting with things in the environment, so what's really needed to understand this is a 3D map of CO2 concentration vs. time for a reasonable scale to identify experimentally what and how much things have an effect on this. In fact, the models that assumed the mixing was uniform were (roughly) the same ones that predicted we'd all be dead by the '90s due to the massive ozone hole that mysteriously shrunk despite an increase in ozone depleting chemicals. Right now models only poorly understand why, in Earth's past, the CO2 level has been ~12 times the current level, but with similar temperatures. Eg, The Cambrian, 542 - 488 million years ago, 4500 ppm, 21 °C Ordovician, 488 - 444 mya, 4200 ppm, 16 °C Silurian, 444 - 416 mya, 4500 ppm, 17 °C Devonian, 416 - 359 mya, 2200 ppm, 20 °C ... Paleogene, 66 - 23 mya, 500 ppm, 18 °C Recent past, 2 mya, 280 ppm, 14 °C Today, 0 mya, 385 ppm, 14 °C So at the very least, naively looking at the last two data points, where conditions are the most similar, we'd expect a 105ppm increase to get us about 1°C, with increases ~1ppm/year (with fairly poor error bars) we'd expect to see about a degree per century at most... but the log fit between the last two points would predict a current temperature about 2 degrees higher than we see. So you can pretty easily see here that there's very little correlation between CO2 and temperature directly. And this is largely due to environmental effects since the climate is in an equilibrium. There have also been volcanic eruptions that have increased CO2 levels by significant amounts for long periods of time which did not increase temperatures. In fact, the reasoning used in models to justify the significantly lower temperatures than you'd expect for 15x higher CO2 concentrations than you see now is the same reasoning that was used in the ~80s to predict that increased CO2 concentrations would cause global cooling . Anyway, the point is that it's a long way to go from the completely true qualitative "all things being equal, more CO2 causes temperature to increase" to a quantitative "adding x ppm to the atmosphere will cause a t°C temperature increase within the next y years." The former is good science, the latter (right now) is bad science. Sadly, the latter is what's done increasingly often. And a lot of people seem (from the papers I've read) to be more interested in continuing to say the latter, rather than to improve models to make it good science. Partly, you can't blame them for thinking like that, because their models have not, on a theoretical basis, improved significantly in a decade or two. There have been big numerical improvements, of course, but that's little comfort to calculate to 10 digits something that's an approximation only good to 1 . They would certainly not be the only scientists to make claims like this on the basis of wishing they had better models. But that still doesn't make it good science.

Originally Posted By: Student of Trinity But there are plenty of opportunities for longer independent projects on basic topics that get written up into an undergrad thesis. For instance, although this wasn't a thesis, I learned an awful lot from an advanced one-semester lab course that had me design and carry out a single simple experiment from scratch, instead of simply following directions with pre-fab apparatus for a weekly lab. That's good. AFAIK, there wasn't an opportunity to do any experimental stuff at my undergrad university like this, other than building stuff in the basement for someone else's experiment. Although I got to write a nice string theory paper as an undergrad, and I definitely learned a lot more than any class doing that. Quote: Post-docs in physics are normally paid quite decently, and allow you to do independent research. In fact, you don't have to do anything else: no teaching, no grant proposals, no committee work. You're nobody's slave. Apart from the fact that you're under huge pressure, because your academic career will grind to a halt in a year or two if you can't generate impressive enough publications before then, it's a good life. In active fields in which a PhD has good industry opportunities, it's easy to get post-docs. In fields like string theory, it's the wall of fire. That sounds good. Although I've heard of several theory people doing postdocs ~10 years, too, though. Although I'm hoping that strings now having some nice applications in nuclear/condensed matter stuff that it may make it a little easier for me to get somewhere. I've heard of a lot of good string people around here having a lot of trouble recently...

Originally Posted By: Student of Trinity Some of this at least is probably more benign that it appears. Climate data is not results from controlled experiments. The observations are sparse samplings from a few hundred places scattered around a whole planet, over a few decades or less. Definitely true. Quote: The simulations are enormously simplified models for the real world. Even more definitely true. But the problem here is that, while it may make good sense to use these models, and calculate with them, and compare them to reality, and improve them, and do as much as you can with them, it does not make sense to predict with them. In fact, the models they use are all pretty well known to have a 100% failure rate for quantitative predictions. And quantitative predictions are pretty much the gold-standard in science! Not that there's anything wrong with qualitative behavior. Qualitative behavior is what's driven almost the entirety of my field from the beginning until now . But qualitative behavior is not something to base quantitative policies on. And that's what I find the problem in the field to really be. Their best semi-quantitative arguments are things like "within 1-sigma models are consistent with warming" okay. But it's also the case that their models are consistent with warming being caused by random fluctuations, natural effects, any of the number of periodic cycles in climate, or man made sources. And the relative amplitudes of these effects are completely unknown. From statements like that, an an understanding like that, it's completely inappropriate to be making any exact claims about their field at all. This is really no different than the "chocolate causes cancer" argument above. "CO2 causes warming." Well, sort-of. But did you know it causes warming roughly logarithmic to quantity (and in fact pretty quickly saturates), or that the atmosphere's absorption spectrum is dominated by H2O? The real mechanisms behind the warming in the model are not really even CO2 increases, since that could not account for all of the apparent warming. So I find the claims that the scientists make in public, at the least, pretty distasteful and misleading. And I honestly do not believe they are the kinds of statements good scientists make. Not to say that the whole field's bad, I've talked with, and heard from, climate scientists and physicists who study these things carefully who are absolutely great scientists. But these are not the people at this institution, are not the people who show up on TV, and are often not the people who the government asks for advice. (c.f., the last paragraph in Feynman's speech above!) And it's very difficult to determine incompetence from not looking at exactly what people've done, and without having some background knowledge in what they're doing. A great example in physics of this is a lot of people (and all of the media) talk about the "alternatives to string theory." E.g., talking to people like smolin or surfer physics guy. Well, surfer physics guy literally wrote down equations (in his paper he published on some forums) which were absolutely batshit crazy. He literally writes equations down that are not defined at all. It's really, literally, nonsense. And there's the "loop quantum gravity" people who write stuff that makes just as much sense. And when they're not writing that they write bizarre rants against how they're persecuted by physics. At any rate, the absolute nutjob statements these people make has not stopped the media from thinking these guys are "new Einsteins," nor has it stopped almost everyone outside the high energy physics community from thinking they're probably saying something reasonable, and we're just quibbling over some detail. Nope, no details, they're just morons. But you're unlikely to know that living outside the community. So keep that in mind the next time you listen to what your favorite news station, political party, or pundit talking about this! That being said, I'm obviously not a climate researcher. But I'd like to think I am a competent physicist, and I have read some of their papers. Though I do like how the news can have a "debate" between "pro" and "anti" "global warming" "scientists" and both of them could not be more wrong. Originally Posted By: Sporefrog For me, I find no reason to disbelieve the opinion of the many, many, many scientists who have statistically analyzed the evidence and found it to be compelling. But you have to understand what that means. What the scientists "agree" on is not what's reported in the media. And there is a huge difference between statements like "our models predict" and "this will happen." Those kinds of statements are often not even comparable. Most of the models I deal with in my work every day have very little to do with reality! But they're still good models to work with because, while they aren't literally reality, can help us understand important features of reality! Although if I were to go on CNN and claim that my paper on mesons in ads/cft makes predictions we can go out and measure, I'd be laughed at! Originally Posted By: Master1 Global warming is really a misleading term. Climate change is more accurate. I recall having it described as just greater variance and less predictability in weather, as well as increased severity of storms and such. I'm no expert, but that's my understanding, and it explains both hot and cold. Actually, "climate" is a much more accurate term . Climate change is already politicized. It's like studying "dynamical change" instead of dynamics! There would be no need to do climatology if it didn't change, huh? Would pretty easily lead to 100% accurate predictions! Originally Posted By: Poached Salmon Only misleading at the local level, as the data seems to show an average planet temperature increase. Many clever people, and many more people who think they are being clever, point at the record snowfalls and cold summers and laugh, sure that this is indeed evidence that global warming is <fill in the blank>. Global warming causes global climate change, which has resulted in climate shift over the past few decades. It may be that it is easier to just call it climate change, since that does relieve a rather large burden from some unimaginative minds. Well, first of all, "global mean temperature" is already dangerously close to being meaningless. Averages are only (extra-)sensible when you have particular kinds of distributions, and the temperature distribution on earth at any time is not one of these distributions, so it's not immediately clear what this means in terms of change. In terms of basics like thermodynamical equilibrium, it's easy. But it makes it hard to correlate things with as easily as things which follow more reasonable distributions. For example, one might guess a more accurate characterization of climate change would be something like "take the temperature at each point on earth today, but at only at 12:00 local time, and average these numbers together." Or only do at at that time and at a certain altitude. Or only at an altitude that corresponds to a specific pressure, or whatever other variables you want. But it's less clear what such a messy thing as "average temperature" means, since it's really an average over a whole bunch of different parameters, not just one. Which goes back to what I was saying about the things they claim not being technically accurate... Edit: This reminds me of me being a smart ass a while ago. I was walking to get something to eat with one of my friends, and it was windy and rainy out. I had a coat on, but he was just wearing short sleeves or something, and was complaining it's cold out. So I say, "oh, don't worry, I'll increase our average temperature!" So I put my hood on.

I've seen a few places who use undergrad theses. I don't get the impression they're terribly useful, though, since you don't really have quite enough background to do very much at that point. As an undergrad, you really don't get to take any serious classes in your major until your third or so year. So only the last two or so you can use to really learn physics. And often you have to take third year classes in your fourth year because of conflicts with gen ed classes. Although if it were combined with a master's type program that would make a lot more sense. Although personally I think having separate degrees could end up being helpful to make it easier for people to switch schools if theirs isn't active enough in the topics they're interested in at that point. I'm tempted to say a master's should be more like a doctorate, since that's what it's preparing most people for, and since that allows more free time to be able to do research rather than classes. Although there're still a lot of intermediate and advanced coursework that could be done. I'm not really sure about post docs though, I don't have any experience with that yet! In principle it seems nice, since it would seem you can have that time to concentrate more on research that you would've as a student, but don't have the responsibilities of a professor. But I don't really know.

Eh? From some of the things I've read, this was way more than that. If I ever received some of the e-mails like those from a colleague, I would be seriously concerned, and would definitely bring it to someone above me's attention. I've seen physicists interpreting data be crucified for a lot less than the things that seem to have happened here, and if I were working with people like this, I'd be afraid this kind of thing could contaminate my carrier. And the withholding data stuff mentioned worries me a lot, too. That's pretty bad. In physics (and other expensive experiments) it's often the case that data is temporarily withheld, but that's so the group of people who just paid for their fancy new billion dollar piece of equipment can use it first. And in almost all cases the data are released eventually, and usually with the publication of papers about it so other scientists can verify their work! This also does not surprise me, because, having seen some of their methods in published work... they are not doing high-quality science to begin with... Their models and statistical analysis are typically pretty seriously flawed. Now, this is not necessarily a problem. Lots of times in experimental science you have situations where what you're looking at is way too complicated to model all of, and you've got things depending on billions of parameters and you can only guess at what 3 or 4 of them might even look like! The thing is, in order to make your science progress, the best thing to do is publish a paper saying "here's our model, it sucks, and this paper is about everything that's wrong with it!" And then, if that's the best anyone can do, a bunch of smart people will look at it and say "well, I think I can add a little bit here" and someone else adds a little bit there, and pretty soon, you have a better model, and you go out and test it. Then, you see it's crappy too, but a little less crappy. And you go on and on until you have something you're marginally less ashamed to be associated with. That's how good science is done! But that's not what's going on here. As an example, when you read the stories in the media like "Scientists prove chocolate causes caner!" So you, being a reasonable person, think "that's stupid, scientists can't possibly have said something that dumb!" And then you go and read the paper they're talking about. And what you find is they injected some chemical into a rats brain. And some of the rats, say one or two got brain cancer. Then the scientists got out their biochem books, and decided that the chemical they injected the rats with inhibited such-and-such protein from binding to something else. And under such-and-such conditions, that can cause cells to mutate in this particular way. And statistics have linked this particular mutation, in combination with some genetic factors, to cancer. And, oh, by the way, that chemical they injected, they produced with chocolate because it was cheaper than buying it directly from the chemical supply company. And the scientists go on TV, and try to correct the reporters, and the reporters smile and nod while the scientist explains. Then conclude the story with "so should I be eating less chocolate then?" And the scientist dies a little inside. In this situation, what happens? Well, you see in the media, "scientists predict 10 degree / century warming due to CO2 production!" And then you read their paper, and it says "models predict warming of 10 degree / century, therefore we'll get warmer by .1 degree / year." And it goes on to say things like "to find the probability of warming, let's use statistics" and you think, ok, maybe this will clarify things. And then they say "given a prior distribution that predicts warming to lie within the range of 3-10 degrees/century with 3-sigma confidence, we find the posterior probability distribution to tell us warming is almost certainly going to happen!" And then you stop reading the paper. And then the scientist comes on, and talks about how it's going to get 1 degree hotter per year and what that would mean. Then the reporter says "so we should driver cars less?" And the scientist says "yes, if we want to decrease temperatures, we should do that!" And then we all die a little inside! The thing is, to do competent science, you have to be a horrible critic of your own work (and others'!). You have to be pretty ruthless, particularly in understanding important data, if you want to be taken seriously. To quote someone much smarter than I on the topic, this is what Feyman, one of the greatest physicists of the century has to say about it, from a Caltech commencement address in 1974 (c.f., full text, http://www.lhup.edu/~DSIMANEK/cargocul.htm) Quote: [...]That is the idea that we all hope you have learned in studying science in school--we never explicitly say what this is, but just hope that you catch on by all the examples of scientific investigation. It is interesting, therefore, to bring it out now and speak of it explicitly. It's a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty--a kind of leaning over backwards. For example, if you're doing an experiment, you should report everything that you think might make it invalid--not only what you think is right about it: other causes that could possibly explain your results; and things you thought of that you've eliminated by some other experiment, and how they worked--to make sure the other fellow can tell they have been eliminated. Details that could throw doubt on your interpretation must be given, if you know them. You must do the best you can--if you know anything at all wrong, or possibly wrong--to explain it. If you make a theory, for example, and advertise it, or put it out, then you must also put down all the facts that disagree with it, as well as those that agree with it. There is also a more subtle problem. When you have put a lot of ideas together to make an elaborate theory, you want to make sure, when explaining what it fits, that those things it fits are not just the things that gave you the idea for the theory; but that the finished theory makes something else come out right, in addition. In summary, the idea is to try to give all of the information to help others to judge the value of your contribution; not just the information that leads to judgment in one particular direction or another. The easiest way to explain this idea is to contrast it, for example, with advertising. Last night I heard that Wessen oil doesn't soak through food. Well, that's true. It's not dishonest; but the thing I'm talking about is not just a matter of not being dishonest, it's a matter of scientific integrity, which is another level. The fact that should be added to that advertising statement is that no oils soak through food, if operated at a certain temperature. If operated at another temperature, they all will--including Wesson oil. So it's the implication which has been conveyed, not the fact, which is true, and the difference is what we have to deal with. [...] We have learned a lot from experience about how to handle some of the ways we fool ourselves. One example: Millikan measured the charge on an electron by an experiment with falling oil drops, and got an answer which we now know not to be quite right. It's a little bit off, because he had the incorrect value for the viscosity of air. It's interesting to look at the history of measurements of the charge of the electron, after Millikan. If you plot them as a function of time, you find that one is a little bigger than Millikan's, and the next one's a little bit bigger than that, and the next one's a little bit bigger than that, until finally they settle down to a number which is higher. Why didn't they discover that the new number was higher right away? It's a thing that scientists are ashamed of--this history--because it's apparent that people did things like this: When they got a number that was too high above Millikan's, they thought something must be wrong--and they would look for and find a reason why something might be wrong. When they got a number closer to Millikan's value they didn't look so hard. And so they eliminated the numbers that were too far off, and did other things like that. We've learned those tricks nowadays, and now we don't have that kind of a disease. [Note: This is the same thing that happened with the value of Hubble's constant. It's changed very slowly from it's first measurements over the years by like an order of magnitude! Although this was partly also due to systematic errors in equipment used to measure it IIRC.] But this long history of learning how not to fool ourselves--of having utter scientific integrity--is, I'm sorry to say, something that we haven't specifically included in any particular course that I know of. We just hope you've caught on by osmosis. The first principle is that you must not fool yourself--and you are the easiest person to fool. So you have to be very careful about that. After you've not fooled yourself, it's easy not to fool other scientists. You just have to be honest in a conventional way after that. I would like to add something that's not essential to the science, but something I kind of believe, which is that you should not fool the layman when you're talking as a scientist. I am not trying to tell you what to do about cheating on your wife, or fooling your girlfriend, or something like that, when you're not trying to be a scientist, but just trying to be an ordinary human being. We'll leave those problems up to you and your rabbi. I'm talking about a specific, extra type of integrity that is not lying, but bending over backwards to show how you are maybe wrong, that you ought to have when acting as a scientist. And this is our responsibility as scientists, certainly to other scientists, and I think to laymen. For example, I was a little surprised when I was talking to a friend who was going to go on the radio. He does work on cosmology and astronomy, and he wondered how he would explain what the applications of this work were. "Well," I said, "there aren't any." He said, "Yes, but then we won't get support for more research of this kind." I think that's kind of dishonest. If you're representing yourself as a scientist, then you should explain to the layman what you're doing--and if they don't want to support you under those circumstances, then that's their decision. One example of the principle is this: If you've made up your mind to test a theory, or you want to explain some idea, you should always decide to publish it whichever way it comes out. If we only publish results of a certain kind, we can make the argument look good. We must publish both kinds of results. I say that's also important in giving certain types of government advice. Supposing a senator asked you for advice about whether drilling a hole should be done in his state; and you decide it would be better in some other state. If you don't publish such a result, it seems to me you're not giving scientific advice. You're being used. If your answer happens to come out in the direction the government or the politicians like, they can use it as an argument in their favor; if it comes out the other way, they don't publish it at all. That's not giving scientific advice. [...]

In some ways that seems a lot better to me. The first year of graduate classes here were pretty much a waste of time for a lot of people here, but they feel like they have to require it for the sake of demanding everyone pass quals on the subjects (which are really nothing more than the same finals you just took, but again). And it seems like that waste of time could at least be made into something contiguous with your previous education in that case. On the other hand, I don't think showing you can pass classes is enough to show someone can be a competent scientist. I've known a lot of people who do well in classes and quals because they just memorize everything, but when I say "hey, I just read about this new thing, what to you think?" I get a blank stare, and an "I don't know." I think (and it's my impression that this is how it used to be) that having a master's in between undergrad and phd work makes the most sense. It actually shows one can understand the basics of his field well enough to apply it to solve an interesting (though not necessarily fundamentally new) problem, which is exactly the kind of skill scientists need to have. Not to mention it is a much better stopping point for people who want to work in industry rather than research, since a thesis illustrates technical competence more than grades do (which IMO don't show anything at all). It would also be endlessly more fun to write a master's thesis than take a half dozen 6 hour tests! That's actually ridiculous enough that I find it personally offensive. Although, given the amount of effort I've learned some admissions people put into reviewing applications, I doubt many would actually read any theses well enough to determine if someone was competent or not... (apparently we can't even get people to review papers for journals properly any more, so it seems this has little hope!)

That's certainly true. But the university's environment has a lot to do with it too. And from most people I've talked with, small universities tend to be far better in this regard, since they lack the overwhelming bureaucracy that tries to mandate how things are done, and are responsible more to their peers. For example, in the large university I'm at, there're rules that say something to the effect of every grad student who passes the qual is required to have a thesis adviser by some date, and the department is obligated to provide one. But because it's such a large department, and many professors don't even know each other, it's a diffuse responsibility. So no one cares enough to say things like "hey this guy is smart, but doesn't have anyone to work with, let's help him find someone." The only people anyone knows are in their research groups, which doesn't help any students if the group doesn't want them, and the only people who feel obligated to help probably want that student anyway. But at smaller schools I've heard of professors going out of their way to help students find work. But to my knowledge no one has ever done anything like that here! Other than vague advice, like "hey you should talk to some people." I know one of the really smart guys here from Caltech has had a lot of trouble finding people to work with, and that's a scary state of affairs! And in what's I'm sure an entirely unrelated story we've recently had like 30% budget cuts and the school's plan is to make up that money AFAIK entirely through raising tuition and increase class sizes. Of course that hits the state maximum yearly % increase long before it's enough to pay that off, so who knows what their plans are to stave off death until then. But, hey, practically every building and courtyard has a very expensive piece of modern art in it! So at least we planned ahead for our financial future here. And I'm sure the artists who made them appreciated the mandated physics classes they had to take for their general education requirements!

Originally Posted By: Student of Trinity Physics programs in North America are, quite simply and literally, elitist. The attitude prevails quite sincerely that only a few specifically talented people should take a degree in physics. The interesting thing here is that that's only half true. I've learned more and more that while physics is "competitive" (at least at the places I've been to or heard about directly) it's not competitive in the sense that "the people who're good at doing physics do well" but more like the people who play along or are willing to solder in the basement or something will do well . Although I've certainly met some smart people, I've also met a bunch of people who've made me gasp at their lack of any knowledge! And I've been surprised at the very anti-student culture (at least at my university) that doesn't really encourage any independent work, or let people stand out for being good at physics very well. This is partly due to my university's personal problems though . I've heard from some friends at other places rumors about professors actually going out of their way to make sure students are not worked to hard or to easy, and actually do things they're interested in. Although I am not 100% convinced this is true based on my cynical experiences .

Originally Posted By: Student of Trinity I still do think that things can be done a lot better than most books manage. But it's a heckuva lot harder to do that than I used to think, because even quite basic physics is astonishingly full of amazingly tricky points. Yeah! No kidding! But the fact that most people are completely unaware of this when they take physics, and most intro professors look at students like they're morons when they notice themselves (since many professors don't know about the issues) is a problem. It's also why only people who work in a field should write textbooks in a field (I do not in fact believe that most intro book writers are even physicists). Your intro mechanics book had better be written by one of the guys who solves mechanics problems for a living (surprisingly not only do they exist but there's a lot of interesting stuff you can do that just hasn't been done). That's why eg, Weinberg's QFT books are so great for learning QFT (the second time). And it's also why people who don't realize what's really going on in qft think some of his notation is a bit insane, but it really highlights important subtle points that you'd miss otherwise! But this is definitely nontrivial to do. On the other hand, one should really arrange things to have all the time they need to write a good book! Originally Posted By: Enraged Slith Just as a general tip to all of you youngsters about to head off to college, it's absolutely crucial that you understand your math concepts, especially when your science classes start requiring you to integrate things for yourself. Yeah, that's important, but certainly tricky. My normal advice is to buy/check out 2 or 3 additional books on a topic that's important, but the problem is that all of the intro calc books that I am aware of are in fact identical! Although I hear Folland has an intro calc book used for honors undergrad classes that's supposed to be very good. There's a book "calculus made easy" or something that has some very nice descriptions of things in terms of the "infinitesimal" approach that calculus was initially developed with (but a more modern notation, but without modern rigor). It's very different than normal approaches, but if you understand carefully why it's identical to the normal limit approach for differentiation and integration, you shouldn't have any conceptual problems for a while. Originally Posted By: Decorated Zombie Veteran You're convincing all of us impressionable youth that college is a waste of time. Bad CFG! I have been told by a number of people "don't do theoretical physics unless you can't see yourself doing anything else!" Although this is more an unfortunate fact of political and administrative environments than science. Originally Posted By: Thuryl I had to teach some geometry to some Year 7 students this week and I didn't feel like making the class calculate the internal angles of every regular polygon up to the octagon, so I made a lesson on straightedge-and-compass constructions instead. That's good. That kinda stuff is a lot more interesting, because it makes people actually think instead of following the recipe that they don't really understand. Although my very favorite thing about learning geometry was learning to use formal logic to prove things. I always went out of my way to prove things by contraposition for a while after that .

Originally Posted By: Master1 I hate students who sit in high difficulty (according to the school) classes but couldn't care less. [...] With all the required topics and smart students, we have challenging classes in topics that few people are passionate about but everyone has to take. Yeah, that's all a big part of the problem. That's why here, we have something stupid like 2000 students in each quarter of intro physics per year. Probably another 2000 in the off-sequence quarters. And who's in there? Pretty much everyone because it counts as one of the required "sciency class" credits. Because, really, you can't be a well-rounded college student if you can't solve the differential equation for a simple pendulum in the small amplitude limit! [Eh, well, actually most people coming out of the class can't since they don't expect you to be able to do any calculus in the course titled "calculus based physics for scientists"... but still] The humanities requirements are even better! Because at my school, there were more required credits in them, but far fewer actual classes. The end result? Well, if you go to a doctor and die in the operating room, you can feel satisfied that while he didn't get to take that extra surgery class that could've saved you, he can appreciate this nice 9th dynasty Egyptian statue in the lobby, thanks to that quarter of art history! Then there's of course the artist who can't quite remember the difference between 8th and 9th dynasty Egyptian art because he had to take all that physics . Talk about poor allocation of resources! Originally Posted By: Decorated Zombie Veteran *Empathizes with cfgauss* Well, sort of. Nalyd's mom is a teacher (at a high school level, and a high school for pregnant teens, so sadly not the best education around) and even she won't shut up about this kind of stuff. Though in high school, it's more the curriculum being dominated by standardized tests than active interference. When I look through math and physics history, I am occasionally a bit surprised when I learn some famous (usually c.1900s) person was a high school teacher. Then again, I'd love to teach kids about math or science if someone would pay me a reasonable amount of money, I was actually in charge of things, and didn't have to deal with all kinds of administrative stuff constantly. In fact, when I do get the chance to talk to young kids, I'm always amazed at how grade school kids can qualitatively understand fairly sophisticated ideas in math that they otherwise wouldn't have seen until grad school. And they usually don't even know it's math until I tell them, and even then they don't really believe me because math is boring and all about memorizing that damn multiplication table . Someone needs to go and tell these standards people that a significant fraction of professional mathematicians don't have that memorized because they know how to figure it out! I don't know how many advanced math or physics lectures I've taken where they'd say something like "so 6*7 is... uuh, well 6*5 is 30... so 36, 41, 42!" Oh--and that reminds me, in high school I taught/TAd math at a community college (arithmetic through calculus). It always amazed me how it'd totally blow people away when I mentioned stuff like "well you can do this quickly in your head because 6=5+1 and you can easily add 5 and 1 without counting!" Because this stuff is apparently not in textbooks. Because it would be cheating. Seriously. Edit: And, this just reminded me also! If you haven't, read what one of the most brilliant physicists ever thinks about the textbooks we use in schools! And the situation today is exactly as it was then, sadly. http://www.textbookleague.org/103feyn.htm Quote: [...]The reason was that the books were so lousy. They were false. They were hurried. They would try to be rigorous, but they would use examples (like automobiles in the street for "sets") which were almost OK, but in which there were always some subtleties. The definitions weren't accurate. Everything was a little bit ambiguous -- they weren't smart enough to understand what was meant by "rigor." They were faking it. They were teaching something they didn't understand, and which was, in fact, useless, at that time, for the child. [...] Now that I think of it, this is the same argument, almost word for word, I had with a physics education person around here the other day regarding the intro physics curriculum....

Originally Posted By: Thuryl duuuuude, i'm a high school teacher and even i don't have to put up with that kind of micromanagement That's not even the beginning of the kind of crap I get to put up with . Well, not anymore, because they don't have money to pay me to do that now. They also don't have money to pay me for research either! Originally Posted By: Master1 Even if you can do whatever you want, that just makes most teachers not do what they should. If they can do whatever they want, they will just do nothing. I think this is definitely not true! The reason most teachers don't do a good job is exactly because of all the micromanagement and administrative crap. If someone came up to me and said I had to teach intro physics from this specific book to this group of 500 people who don't care at these times each day and go over these topics and conform to this way of talking about things and tie in with these in class worksheets and with these labs and have tests on these dates (that are written by someone else so every class gets identical ("fair") tests) and assign these specific homework problems.... etc, etc... I would not do a great job either! Of course the biggest problem is having students who mostly don't care. Although it's a system with feedback. We're limited so much we can't have fun, the students see us not having fun so they don't enjoy it, we see them having no fun and don't enjoy it.... And not being able to go over your own topics can be devastating too! I mean, there are a lot of amazing, clever, and weird things in intro mechanics that are very easy to understand, and shed light on important ideas that are not covered in any textbook that I know of! And were never covered in any class I've ever taken! (In addition, of course, to the mistakes, and technically-not-mistakes-but-will-confuse-any-reasonable-person-who-reads-them-es that the intro books are full of.) Although I've noticed some of the physics for non-scientists classes go over some stuff a little. In fact, I've noticed in TAing labs for intro physics and physics for humanities classes that the physics for humanities students tend to understand things substantially better! Once, when I was grading for both classes at once, I accidentally mixed up some of the labs from the non-scientist class (which is credit/no credit only) with the scientist one (which is graded), and accidentally graded them. (The labs are identical because no one's bothered to make separate ones in this university's existence). They all (5 or so) got nearly 100% except for one student who didn't do the whole thing, which is typical quality for that class. The average grade on the for-scientists class was more like 50%, and there were only 1 or 2 nearly perfect scores, which is typical for them as well. I've pointed this kinda stuff out to many of my peers and they don't believe me! Then I say stuff like: Originally Posted By: me "They never talk about why things are like they are in the for-scientist classes! They just ask them to memorize things! Did you know they don't even talk about what F=ma means, or why it's =ma and not something else? Or *why* energy or momentum are conserved!?" Originally Posted By: them (after blankly staring at me for a few seconds) "But F=ma just, uhh, is.... conservation comes from Nother's theorem and they can't under..." Originally Posted By: me "Did Newton know about Nother's theorem? No, he didn't! How do you think they figured this out then!" Originally Posted By: them ... Yeah. Abysmal! To top it all off their focus on "memorize these things and calculate stuff" results in students not being able to do calculations other than the ones spelled out for them in the textbook! But go ahead, force us to teach that way, you've been doing physics education for years and obviously know what you're doing based on these decades of students not knowing how to do physics! Can you tell I'm annoyed at these people? I once, as an undergrad, was annoyed that they didn't have a baby QFT for undergrads class. So I, and a friend, made our own. We made a lecture class teaching baby QFT, in our own free time. We had like 30 undergrads and master's students show up. I had multiple people thank me and tell me I did a great job and they never understood it until I explained it to them. To this day that terrifies me.

Originally Posted By: Student of Trinity I'd still love to see how Lorentz invariance can introduce Newton's constant. My vague recollection of carefully going through this was that it's related to how you get the "gauge fields" out. Although I don't think it was literally the coupling constant, it was something like how you can rescale A^mu to eA^mu to get rid of / add in the coupling constant in QED. Quote: At least in Wald's discussion, a vierbein plus the Minkowski metric is so directly equivalent to a (pseudo-)Riemannian metric that it's all really just an equivalent alternative formalism, and not any logical reduction. (If I remember rightly, to get GR you have to impose relationships between the vierbein and the spin connections, and these are of course tantamount to the Riemannian formulation.) Essential for treating spinor fields in curved space, though. Yeah, that's exactly right. And that's why technically this global->local formalism gives you something slightly more general than GR. You still make some simplifying assumptions, like getting rid of torsion to get normal GR. But those were steps you had to take anyway to get to GR. Quote: I started off in high energy theory, while string theory was in its second death, but got more interested in non-equilibrium quantum stat mech than in trying to guess the Planck scale theory from Higgs scale data. (Once I realized that the previous 16 orders of magnitude had taken us from banging rocks to QCD, I became deeply skeptical of attempts to go as far again within the very conservative approach of string theory.) Well, the reason I like strings, and the reason I take it seriously (aside from the very nice phenomenological-ish arguments given in intro string texts) is that it's sort of the ultimate generalization of this general gauge structure idea. Although it's not always particularly easy to see. But it's part of the reason so many theorists think string theory is "obviously" correct, since it's the only tractable, sensible generalization of QFTs. (For certain values of "obvious," "correct," "tractable," "sensible," "generalization," and "QFTs" of course!) Although we've got AdS/CFT now which is pretty nifty! So we can do at least one field theory . Quote: So for the past dozen years are so I've worked theoretically on stuff you can do with quantum gases. Nowadays I say my theme is quantum thermodynamics. Statmech is not something that my school's focused too much on (well, recently that seems to be the case with all subjects, but that's a different story), so this is an area that I'm embarrassingly ignorant on . But what I have read about it looks pretty neat. Quote: I'm currently a professor at a university in Germany, although my German still isn't very good yet. This semester I'm teaching electrodynamics, and shouting 'Mush! Mush! On, you huskies!' to my grad students. Well, feeling like shouting that. That's fun. Electrodynamics has a lot of fun stuff you can talk about. Just make sure to actually talk about it . My class was just "boundary conditions!" and "series expansions!" and god it bored me to death! I'm still a grad student though, so I don't get to teach anything fun yet. All I've gotten to do, aside from teaching I did on my own earlier, is to babysit students while they fill out worksheets in "class." That's right, my department thinks that's an excellent use of time. Oh, and it really is babysitting because we can't like, give them answers or anything, that'd be crazy! And that they think grad students are not competent enough to actually teach. (Yay internal politics!) Although I don't have to teach now because we ran out of money!