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About rbc

  • Rank
    Veteran Member


  • MBTI
  • Enneagram
  • Global 5/SLOAN
  • Personal DNA
    Reserved Idealist


  • Location
  • Occupation
    Physicist Mercenary
  • Interests
    applied math, theoretical physics, neurobiology of behavior, books, hyperdetailed simulation games
  • Gender
  • Personal Text
    Always carry a gyroscope. You'll never fall; you'll just precess.
  1. Are you still around, rubiks cube?

  2. While I was in college in the early 90s, Massachusetts was in the process of passing an assault-rifle ban, so one of my friends organized a trip to a range for one last spin. He brought an AR-15, an AK-47, a FN FAL and an H&K G3. The FAL was by far the heaviest, and also my favorite. It made me feel most like I could easily make it do what I wanted. The AR-15 was so light it was hard to aim consistently, and I hated the sight. The G3 was the one I would have wanted if I had to carry one with me all day (the FAL seemed better suited for static defense). The AK lived up nicely to its reputation of "Jammed? Smack somebody with it!" :)
  3. Sometimes I think I should try. Not always, but sometimes.

  4. thanks for this. it won't work, but thank you for trying.

  5. I think it's quite common, especially for INT types. I didn't realize I did this until I tried to understand my INTP father's behavior. What he and I -- and many, many other introverts, I am certain -- separately found is that if you pretend to be a bubbly extravert, no one will look closer, so you can better defend your core self from attack when forced for some reason to interact with others. Interestingly, though I can pretend to be E or S, I seem completely incapable of pretending to be F.
  6. It is not an assumption. The reality and practical utility of g is an empirical fact. Everyone actually doing psychological research knows this. The larger society (including, perhaps especially, journalists) doesn't want to believe this, but it is nevertheless true. No one set out to prove g, but no would-be psychometrician has ever managed to avoid discovering it, even when they were explicitly trying not to find it. As a result, there is no longer any shadow of a doubt that g is important and real. It is not a competition! Fluid/crystallized, verbal/visual, etc., are only *aspects of* g, not alternatives to it. Every attempt to construct a multi-factor theory has always found that their posited factors are not independent; in fact, they are mostly the same. g is exactly that sameness. Saying that fluid/crystallized is an alternative to g is exactly like saying that because one human has two legs, it is therefore not one organism but two independent ones. Those claims are incorrect. It is theoretically quite easily falsifiable. However, every practical attempt to falsify it experimentally has instead increased support for it. That is exactly how science works when the current theory happens to be mostly correct. Not true at all. Instead, they try to ask as broad a range of questions as they can imagine -- anything which could plausibly be linked to anyone's concept of a mental ability. The constantly observed experimental fact is that all of those questions, even when on the surface they seem very different, are in fact all quite strongly related to each other. That relationship is g. Then when one measures nearly any life outcome (salary, health, chance of death in a car accident, dogmatism of beliefs, ability to read a bus schedule...) and a whole bunch of possible causes, g always turns out to be one of the most important variables, often the most important. As a result, I am now annoyed by any sociological study which doesn't include g as one of the things they measure and try to control for, since failing to do so drastically limits the study's explanatory power. g is not a guarantee of anything, but it is helpful with everything. Well said! This is exactly true. I once wrote lots of posts about IQ, but it's been a few years since my last one. Please consider this, this, this, this and this to be pasted into this post at this point.
  7. Mmm, yes and no. Exactly. In fact, the name "big bang" was coined by an opponent of the hypothesis, who thought it was silly. But that's all any scientific theory is. In the words of the authors of Numerical Recipes (two of them astrophysicists), "At best, you can substantiate a hypothesis by ruling out, statistically, a whole long list of competing hypotheses, every one that has ever been proposed. After a while your adversaries and competitors will give up trying to think of alternative hypotheses, or else they will grow old and die, and then your hypothesis will become accepted. Sounds crazy, we know, but that's how science works!" (page 609 of the second edition in C) Of course not. Even if you could create a new universe in the lab, that still wouldn't prove that's how this universe was formed. The only thing any cosmological theory can do is suggest mechanisms which might possibly have produced the few things we can measure from way back then, like the microwave background and the flatness problem. You have misunderstood what the big bang theory means. It is not an explosion *in* space, it is an explosion *of* space. Sadly, we have no way to discuss it except with equations (which we don't know are correct) or metaphors (which we know are incorrect). Galaxies are all moving away from each other *on average*, but there are large, local, and apparently random deviations from the average. The concept is called peculiar velocity. In this case, peculiar doesn't mean "how strange that this would happen", but rather "every galaxy is observed to have motion somewhat different from that of all the others".
  8. Exactly this. Gardner is just out to sell books. He stopped doing real science decades ago, because it would hurt his sales if he admitted he'd changed his mind since then, which pisses me off. There are interesting factor structures within g, and there are heritable talents for many things, but the ways this crap has been misused just muddy the waters to no good purpose. He also once said he didn't think you could truly exhibit any of these without at least a 120-130 IQ, which means that even he knows they are at best components or side effects of g. I mention side effects because of the kinesthetic bit: when the US Air Force tried to design dexterity tests to select who would be a good pilot, they discovered to their surprise that they had actually developed an intelligence test instead. Sure, eye-hand coordination helps in "pursuit rotor tracking", but being able to mentally *predict* where the rotor is *going* to be is much more useful. This is in fact one of the clearest biological indications of intelligence. Reaction time to even very simple stimuli (here are four buttons; when one lights up, press it) is significantly correlated with IQ; smarter is faster. Also important is efficiency and consistency of the process. Functional MRI measurement of cortical glucose metabolism correlates almost as strongly (.7 to .8) with the score you get on the IQ reported by the test you were taking inside the MRI machine as two IQ tests of different brand names correlate with each other (.8 to .9).
  9. Thanks for the comments on tank rounds! As for physics, I meant more of how some phenomena interact with many kinds of matter, and not others. For instance, if magnetic waves interact with sub-atomic particles, as well as standard particles...why is it that the waves interact with some and not all? Just as gravity interacts with nearly everything. I see harmonics, and I cant help but consider that perhaps gravity and magnetism act just like sound... that forces only interact because the particles and atoms are the right "size" to catch the "frequency" of a force, just like a glass picking up harmonic sound waves... while other objects are totally unaffected. Is there any theory on why forces interact with seemingly unrelated particles on entirely different scales?

  10. I like to play very detailed and complicated military history simulations, such as the Europa series, the Operational Combat series, and Advanced Squad Leader. The play time of 6 hours listed for Scorched Earth is either a typo or a sick joke: the game has over six thousand half-inch cardboard counters and nearly 30 square feet of map! The game can take 6 hours just to set up. In high school, I spent an entire summer playing it -- once. It took all summer to play it once, putting in more time per week than a full-time job. It was glorious!
  11. In response to your question, we can directly influence them -- it's just that electric and magnetic fields are the easiest way to do that. A cathode ray tube, like in an old-style non-flat-screen TV or monitor, is basically a tiny particle accelerator. It uses electric fields to accelerate electrons, and magnetic fields to steer them. The gigantic rings at CERN, Fermilab and the like do exactly the same thing, just on a much bigger scale, because we want to get them going much faster. The reason for that is, as you say, to see what happens when we smash them into each other. Fermilab's web site had the best description I've ever seen of what the colliders are for: it's like smashing two ping-pong balls together so hard, that they turn into bowling balls! Then the bowling balls decay into a shower of tennis balls and golf balls, which then further break down into ping-pong balls again. This is like running a nuclear bomb in reverse: they're both based on E=mc^2, but nuclear reactors and bombs turn mass into energy; particle colliders turn energy into mass.

  12. Great stuff! I'm a military history buff as well as physicist, but this post has lots of detail about tank rounds I never knew before. Thanks!

  13. While searching for a reference to footnote what I had originally written, I stumbled across a recent thesis which claims it does: chapter 5 is called "Unitary Proof of the Second Law of Thermodynamics". I don't really want to shell out 30 bucks to figure out whether this guy has finally explained "the arrow of time", but it's Springer-Verlag publishing for University of Tokyo, so it seems legit at first glance. Perhaps your uni library is already buying a copy. That said, the way I have come to look at it is that entropy measures all the other stuff you didn't bother assigning to any other quantum number. I just discovered that this is exactly how Wikipedia describes it: "Entropy may also be viewed as a physical measure of the lack of physical information about the microscopic details of the motion and configuration of a system, when only the macroscopic states are known." Sure, the S matrix is still unitary, but no one in their right mind would actually try to use the S matrix to calculate thermodynamic outcomes! Irreversibility and entropy growth are the same thing, in that if you throw away information (increase entropy), you can't go back to where you were, because you no longer actually know where you were. You lost track of it, because just thinking about writing the individual wave functions of the 10^23 helium atoms which well approximate a few liters of an ideal gas should make your pencil quake in terror. Entropy is fundamentally a measure of information: it is the log of the number of states which all have the same value of the macroscopic, average, approximate parameters you did measure (temperature, pressure, and so on). The analogous idea in operations research goes by the name "partially observable Markov process". QM is as pure Markov as anything ever gets, but the most important word is *partially*. You don't know exactly what the state of the system is, because so many of the possible ones would produce identical results to the (relatively simple) experiment you just performed. It's like when you have to "diagonalize the perturbing Hamiltonian in the degenerate subspace", in my favorite bit of physics jabberwocky -- you only measured some of the eigenvalues which describe the system, so the wave function only partially collapsed: you still have large amplitude in a whole family of states which aren't distinguished by the measured quantum number. It is also important to note that the "laws" of thermodynamics are NOT fundamental, at least not in the way they are commonly stated! In stars, heat routinely flows from colder to hotter. One could argue (correctly) that in those cases the whole concept of "temperature" is poorly defined, but it is nevertheless true that at the surface of every standard, shining star, energy flows from areas where there is less of it per volume (the photosphere) to areas where there is already more of it per volume (the corona). An intro class in plasma physics will quickly make you realize that Boltzmann and his buddies only found what they did because at "standard temperature and pressure" the distribution of particle velocities in the common terrestrial states of matter has a very specific form. Where that form of particle velocity distribution is not found -- namely, nearly the entire observable universe -- you need an quite different approach to thinking about thermo.
  14. You're welcome! :) I first used a variant of that phrase while standing in line to vote, just two months after starting my grad program. The person voting in front of me was a mother with her young son, who was complaining loudly to the poll workers about how much harder first grade was than kindergarten, and now he got as much as ten minutes of homework each night! I leaned down and said, "Excuse me, but I think you ought to know that I am in seventeenth grade." I will forever treasure the look of astonished horror on his face. :devilish:

    Also, in the latest version of the endless silly VR thread, I tried to answer your question on QM and thermo. In short, I think they're very compatible.

  15. I stole "18th grade" for my OKC profile. Figured I'd at least give you credit here. :p