Jay

Jay

  • Commented on The morning after
    In my experience, problems come from: Human nature: 75% Inconvenient physics: 25% Use of dodgy numbers: 15%...
  • Commented on The referendum question
    The Simpsons' groundskeeper Willie has weighed in on the subject, just in case you wanted the viewpoint of a homicidal, drunken, deranged, stereotypical Scot. https://www.youtube.com/watch?v=W6vDzf-wSbk...
  • Commented on Wag that puppy
    I am particularly impressed by the foolishness of movie-makers--who are themselves illusionists--when they are tricked In Hollywood, I get the impression that everybody's faking it all the time, everybody knows it, and calling somebody's bluff is considered rude....
  • Commented on Martial arts and the cycle of bullshit
    One of the best overall rules for fighting is to try not to let the other guy set the terms. If you're attacked, your goal is to break contact. If you're doing the attacking (and you probably shouldn't be), then...
  • Commented on Martial arts and the cycle of bullshit
    Part of the difference is in how you hit. There's a big difference between aiming at the surface of the target and aiming at a point about six inches behind the surface. The first hit is a tag; the second...
  • Commented on Martial arts and the cycle of bullshit
    I was a poor student of Tae Kwon Do, but my instructor was good. On day 1, we covered fighting. Eyes, throat, balls, kneecaps. That was our fighting instruction. The rest was TKD....
  • Commented on The referendum question
    You could be right. I've used helium-3 in the lab before (good NMR nucleus), and I was told that it had come from weapons refurbishment, but maybe they're doing things differently now....
  • Commented on New guest bloggers: Tricia Sullivan and Kameron Hurley
    If you want to attract physicists, don't pop the popcorn. Unpopped kernels can be approximated as spheres, and physicists like that....
  • Commented on The referendum question
    intercontinental rockets aren't exactly maintenance-free turnkey items with a multi-year shelf-life It's also fortunate that fusion bombs tend to go bad over time as the tritium decays....
  • Commented on The referendum question
    The US constitution delegates foreign affairs unambiguously to the federal government. As a result, the US tends to seem more unified from outside than from inside....
  • Commented on The referendum question
    The solution to this is nuclear weapons. Great. Now what's your solution to having large numbers of people (sometimes erratic, usually stressed, occasionally drunk) with their own nuclear arsenals?...
  • Commented on The referendum question
    the kind of nationalism that brought us the Great European War ... is pretty much dead. That may be true in western Europe. It's not at all true in the U.S., China, or (from what I can tell) Russia. India's...
  • Commented on Crib Sheet: Neptune's Brood
    Only that, if antimatter did have this unlikely set of properties, it might move faster-than-light drives from the "impossible according to current physics" bin to the "ludicrously impractical, but not literally impossible" bin....
  • Commented on Crib Sheet: Neptune's Brood
    The last I heard, CERN was trying to measure the gravitational polarity of antihydrogen, but hadn't nailed it. It isn't easy weighing a few hydrogen atoms; electromagnetic effects are many orders of magnitude stronger. If you have more up-to-date information,...
  • Commented on Crib Sheet: Neptune's Brood
    Sure. Now consider the hypothesis that antimatter has a negative mass for gravitational purposes and a positive mass for inertial purposes. Normal matter doesn't work that way, but antimatter might for all we know. Negative gravitational force on positive inertial...
  • Commented on Crib Sheet: Neptune's Brood
    The conjecture isn't quite that primitive. It's more along the lines that a positron is essentially a hole in the quantum field where an electron ought to be. As other potential-electrons in the quantum field get attracted to the gravitational...
  • Commented on Crib Sheet: Neptune's Brood
    Sorry. Stopped....
  • Commented on Crib Sheet: Neptune's Brood
    We agree that photons have energy and momentum, and don't exist at rest. We disagree on whether it's valid to divide that momentum by c to get a mass, but that's a distinction so subtle as to be essentially philosophical....
  • Commented on Crib Sheet: Neptune's Brood
    Photons do, in fact, have mass. E=mc2. Take the energy of a photon, divide it by c2, and you get its mass. It's not a big number per photon. Because photons have mass, they carry momentum, which makes lightsails possible....
  • Commented on Crib Sheet: Neptune's Brood
    antimatter is matter with its electric charges reversed. Both act the same to gravity AFAIK. That's the leading hypothesis, but it hasn't been experimentally validated because we've never actually made enough antimatter to weigh. The last time I checked, the...
  • Commented on Crib Sheet: Neptune's Brood
    That sort of thing requires, as Kaku notes, large quantities of "negative matter". We don't have any negative matter, or even know what it might be. It is conceivable, but highly controversial, that "negative matter" might be antimatter. In which...
  • Commented on Crib Sheet: Neptune's Brood
    I think you're seriously underestimating the spread of the beam and the power necessary for the lasers. Remember, the recipients won't be able to spatially resolve the signal from the nearest star, so the sun is providing broad-spectrum background radiation....
  • Commented on Crib Sheet: Neptune's Brood
    The beam spread is big enough that, even if you used an impractically large laser, a send rate of an hour or so per bit, and a big array of photon counting detectors on the other end, you'd probably drop...
  • Commented on Crib Sheet: Neptune's Brood
    I never said I had. I was just asking a question. And explaining a physics point about lasers, for what that's worth. These sorts of questions are why I prefer fantasy; the author makes up the rules to serve the...
  • Commented on Crib Sheet: Neptune's Brood
    (Not to mention that there is no way to transmit information between stars without the laser beam being so wide when it arrives, the entire star system can read it. And 120 star systems BEHIND it.) For anyone who saw...
  • Commented on Crib Sheet: Neptune's Brood
    They do pay it back: that's the whole point. How? Do they physically ship economic goods? Paying in digital currency doesn't help; we have plenty of numbers right here. How can they actually transfer useful, valuable resources to their lenders?...
  • Commented on Crib Sheet: Neptune's Brood
    I'm a bit confused about the idea of currency backed by the debt of extremely distant people who will never pay it back. It seems to me that this currency should be valueless, in the same way that a bond...
  • Commented on Apology
    I suggest that something like "Gruinmarkt Saga" has the right combination of recognizability for fans of the series and independence for the newbies. Any distinctive, recognizable proper noun from the first series should do as the first word, since Gruinmarkt...
  • Commented on The Ferguson Question
    One word: racism. Of a kind qualitatively alien to your (British) experience. That's a big part of it. The rest is fatigue. To white Americans, talk about racism tends to go in the same mental folder as global warming, peak...
  • Commented on The Ferguson Question
    correction: I don't agree with a lot of things Fred writes. I really should use preview more....
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