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Everything posted by Schneibster
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idontknowwhyijustknow on gravity
Schneibster replied to idontknowwhyijustknow's topic in Speculations
Matter follows the least energy geodesic. Other matter warps the least energy geodesic's shape. So does acceleration. This, essentially, is General Relativity; I certainly don't mean to imply that's all there is to it, but it's the most important concepts of it, idontknow. -
idontknowwhyijustknow on gravity
Schneibster replied to idontknowwhyijustknow's topic in Speculations
The best answer to the OP is, I think, "yes." i mean to be somewhat amusing, but not sarcastic; in fact, it can be interpreted either way, theoretically. However, although we've figured out how to represent it as a field theory (General Relativity), we have not figured out how to represent it as a quantum theory (Quantum Gravity), and thus we cannot even imagine its Gravity Quantum Field Theory. We can only speculate, and try to constrain whatever eventual quantum gravity theory we will eventually, when we figure out the math, discover. This theory will obviously deal with quantization of the universe that we perceive as a superposition of fields. Techniques as powerful as the Yukawa coupling theory that allows scalar fields to be related to four dimensional tensor fields like the Dirac field that describes fermions will be required. We can, in fact, knowing what types of fields are involved, make good conjectures about what a final theory will look like based on what we have now. We are, in other words, quite close. We may in fact already know the required techniques and not yet have applied them in the correct manner. I don't expect to be famous or figure anything out, but I think someone might before the day I die. This is a truly awesome time to live; I have seen the confirmation of the Big Bang, and of the Inflationary Epoch. I am stoked. -
Because...? Frankly on just as much evidence as you have presented I say it does work and you are lying. Update: it has been brought to my attention that this could be interpreted as me saying you're lying. I'm not. I'm saying, rhetorically, that you don't have any evidence. My apologies for any appearance of insult. My intent was to be sarcastic, not insulting. Please forgive me.
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It's a justification for these small ones. However I think they've got big ones we're not seeing any videos of.
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Good question. +1. I believe your first statement is correct: the aim of the troll is to disrupt, annoy, irritate, and create drama. But I think your hypothetical "good troll" is not truly a troll. I'm not saying they're not trolling; they might be. But they're not there to be a troll. The true troll thrives on watching other people fight. I don't. I think there is a cultural tendency to encourage them to think and behave in accordance with their emotions rather than their rational thoughts; some (most, unfortunately, in my generation; this seems to be changing) succumb to it, some do not. Independent dispassionate thought is certainly not the sole province of men, and no more is irrational, herd-driven, emotional reaction the sole province of women.
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I think it's pretty clear from the way they're talking to the reporters from FP that they figure to make them a lot bigger. I'm interested in the magnetic engineering, actually. It has applications in space flight and fusion. A true railgun uses electric or magnetic linear acceleration. I would expect the accelerator to run half the length of a ship or more, with a final (comparatively) short barrel to provide final direction. I wouldn't expect more than a few degrees' off-axis aiming from the main axis of the ship. I'd expect a projectile in the neighborhood of a ton. I'm thinking this may be more of a rail-boosted gun, with a sabot penetrator. Sexy, but not really a "rail gun." Just kind of a hand-wave at it.
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NASA releases photo of light coming of ground on Mars...
Schneibster replied to Moontanman's topic in The Lounge
I gotta go with swansont here. I'll only make one minor point: Mars does have an atmosphere so theoretically there could be some scattering, and there is also dust. Although Martian dust storms are pretty impenetrable (as I have had many occasions to swear at after spending all afternoon getting prepared and then finding it impossible to see anything but a reddish-orange disc). Later: Ice? Steam? The rectilinearity of it does, as swansont says, look like a couple hot pixels. How many pictures have the feature in them? Has NASA said anything? The site we're looking at is a bit... errr, sensational. Not to say anything nasty about someone's favorite site. -
Sure.
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Why can't we go faster than light?
Schneibster replied to kirbsrob's topic in Astronomy and Cosmology
You're still not answering my question. I started to do what you ask ("please explain"), and you didn't agree with me on the basics in post #77, and you won't tell me what you disagree with. You keep bringing up extraneous material. I'm sorry, I don't intend to let go of this until you've answered it. I don't build houses on foundations of air. Until you agree with the basics I don't see how you can object to their results unless you say what basic you don't agree with. Which one of the basics in post #77 do you disagree with? I am becoming impatient myself, now. If you think can show me something wrong with my reasoning, then show me something wrong with my reasoning; so far you can't. Oh, and incidentally I made another mistake; I should have said Einstein tensor, not Ricci tensor. It's actually mostly the Ricci tensor but we should be rigorous. It does not, however, make any difference to my point. And I do not intend to move on to your other points until this is cleared up. Sorry but if you're going to tell me I'm wrong you're darn well going to tell me how. -
I couldn't listen to the video, just watch it; something funny with my system no doubt. I read the article and extrapolated from "rail gun." Whatever they're doing, it's not technically a rail gun, which is purely electromagnetic. I'm still trying to figure what's making flames come out the muzzle. The sabot trick was what they used for the penetrator DU rounds in tanks; I guess you're familiar with the details of that, swansont. Obviously what they're doing there is barely capable of hitting a single hard target, a tank or (in the video) truck. Thanks for running the numbers, John Cuthber. I was gonna get up today and do that. You're right, it'll take a heckuvalot more velocity, or mass, to hit hard enough to outperform, say, the New Jersey's main guns which throw a projectile the mass of a Volkswagen some twenty miles or more. (I'll go look up the details if anyone's interested.) This thing they're playing with in the video is a toy compared to that.
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23 pounds, delivered at Mach 7 a hundred miles away. This explodes like a nuclear weapon, without the radiation or the fallout. No explosives. It's just the kinetic energy of the slug. All heat nothing more. Iron is presumably the best material. It's highly magnetic and therefore ideal for railgun acceleration. http://complex.foreignpolicy.com/posts/2014/04/07/watch_the_navy_s_futuristic_star_wars_railgun_blow_things_up This article is from my favorite foreign affairs site. You will have to register, but you will be able to view ten free articles every month, and comment on them. If you don't want to register, then here is the direct Vimeo link: Bear in mind that actual use of the weapon against targets has never before been shown on any medium. I doubt this has seen public viewing on a science site up until now. Enjoy.
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Feed it back in! This is actually a US Navy project, and they claim jet fuel for $3/gallon. http://www.nrl.navy.mil/media/news-releases/2014/scale-model-wwii-craft-takes-flight-with-fuel-from-the-sea-concept The US Navy has always tried to be green-- it makes them more effective. This little trick could make them no longer require fuel from land for an aircraft carrier; just food and clothing and cleaning supplies. And people. And wherever they went they'd reduce CO2.
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In this recent paper from Michael Mann, the recent so-called "global warming slowdown" is shown to be indistinguishable from the Atlantic Multidecadal Oscillation, or AMO, previously called the "NAO" or "North Atlantic Oscillation" before its full character had been measured. Dr. Mann's original "Hockey Stick" paper was based on study of the NAO, so this is familiar data territory for him. Mann says, So another denial falls by the wayside, and global warming wins again. Full details are available here and I will be fairly available for questions unless ajb takes up all my available CPU cycles.
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I was gonna gig you on that use of "constant," speaking of I think it was a true triumph that the Gravity Probe B folks managed to find their problem, and not only that but correct for it and reanalyze the data. Now THAT required asking the right questions. (A good schneibster always asks good questions. I am a connoisseur, IOW.) I think they found out what the Pioneer Anomaly was, last time I checked. Extra heat radiation pressure from the reactor?
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This is a measure of the expansion of the universe at high redshifts (z > 2) to unprecedented accuracy: circa 2%. This is using the new Baryon Acoustic Oscillation method pioneered by BOSS, this time with three times as many individual objects measured as previously to get the original high resolution results. The current measurements use over 150,000 quasars, as opposed to the last results which used 48,000 and the original survey results which used only 16,000 quasars. http://newscenter.lbl.gov/news-releases/2014/04/07/boss-quasars-measure-expansion/ This approach obviously is one of the most effective possible, and it's good to see astronomers starting to gain the data processing expertise to identify the algorithms to achieve these results. We can look forward to surveys of this type of a million objects in the next decade (and that's pessimistic). As it is, we already have SDSS surveys with photometry of over 500 million (half a billion) objects, and spectra for over a million of them. And the surveys are automated, computerized, and ongoing.
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Flaky buttermilk biscuits
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Flaky buttermilk biscuits are one of the foods that take me back to my childhood in my grandmother's kitchen.
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In modern cars they can blow confuse the mixture computer, which fails safe and turns off the gas. (I don't think they're going to use something that will blow peoples' computers on the far side of the freeway.)
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As davidivad hints, there are hints about the construction of such devices most of which involve magnetrons and ultracapacitors and vaporize their wires. You can find a lot of sites of varying credibility that talk about them. I've never stepped up and done the math and engineering to prove it, but my sense of the magnitudes involved says your friend is not being outrageous at 5 meters distance, but I'd be surprised if it would actually smoke the circuits as opposed to just temporarily interdict communications. A true EMP will burn transistor junctions. That takes a lot of power. I mean a lot. The first EMPs were made with kiloton (i.e. terajoule) nuclear weapons. You really don't want a terajoule being suddenly released anywhere in your near neighborhood even if you have a blockhouse. And you sure as heck aren't doing it with a magnetron the size of your fist. I've seen articles that claimed a thousand pounds of ultracapacitors and a magnetron the size of a watermelon and worked over a distance of hundreds of meters/yards, no more. It seems like a good way to smoke all the electronics in an enemy tank; needs work to be feasible in aircraft. Interesting as an anti-missile close-in weapons system, fry the electronics before the missile can get close enough to hurt you. Need some serious cybernetics work though before it would be practical. Also you'd need to have shielded systems yourself to fire it off; it's just not that easy to make a thing like that all that directional. The backlash could smoke your fly-by-wire computer. After which you become aerodynamically unstable. At Mach 2. Bad idea. Think fly on freeway waiting for the windshield. I've seen articles that talked about purpose-designed EMP nuclear weapons, blown off in the ionosphere to maximize the pulse and spread it over a continent. Megaton-range devices are discussed IIRC. Megawatt radar arrays on guided missile cruisers of the great powers are said to be able to smoke the electronics on aircraft that fly through the beam too close; this is at the edge of believable with systems fifteen years old, and eminently possible these days as the synthetic aperture phased arrays have crept up into the tens of megawatts. Which kind are you talking about? Or are you talking about another technology?
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Why can't we go faster than light?
Schneibster replied to kirbsrob's topic in Astronomy and Cosmology
Sorry but if you won't answer questions I can't figure out where you've made your mistake. -
Your understanding of vacuum energy as measured in a Casimir apparatus seems correct to me. Specifically, the waves between the plates are less than the waves outside the plates. The amount, however, is not infinite. So your objection doesn't look correct to me, but not conceptually; only in terms of your assumptions about the quantities involved. OTOH, it's several orders of magnitude so your objection isn't ridiculous, just ruled out. Remember that although there may be an infinite universe outside the plates, only the waves that strike the plates register; and that's as true on the outside as the inside. This accounts for the frequent statement that expansion happens in the empty space between galaxy clusters. It's because it's not flat space inside them, but it's flat in the space between. If we measured the Casimir force in flat space it would be stronger. This latter is the experiment we'd need to perform to prove it.
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The Bay of Bengal and the Marshall Islands are good candidates for the next wave.
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Why can't we go faster than light?
Schneibster replied to kirbsrob's topic in Astronomy and Cosmology
So you deny something from that post? Could you be explicit about what you disagree with, please? I'm unclear from what you've said what the problem is. All of those propositions look fine to me and you're in the process of agreeing with each one piecemeal. So far you're getting impatient with me trying to figure out what you think is wrong. Maybe if you'd say something other than "your conclusion" and start discussing why the conversation might be productive more quickly. That conclusion, I'll point out, was not mentioned in that post, so actually you still haven't answered my question. Meanwhile, fine, so you admit mass comes into the Dirac equations for fermions through the Yukawa interaction with the Higgs scalar field, and you admit that the Dirac field defined by those equations is explicitly specially relativistic. Right? Now, do you deny that the rest mass that the Lorentz transform acts upon is the rest mass determined by the Yukawa interaction with the Higgs field? BTW, not sure what the claim that the Dirac field, i.e. the fermion field, is not Lorentz symmetric, is based upon. In fact the anticommutation of the half-integer spin fermions is determined explicitly due to Lorentz symmetry; it is therefore responsible for Pauli Exclusion and their other obedience to the Fermi-Dirac statistics. I have no idea what claiming the Dirac field is not Lorentz symmetric means. -
Why can't we go faster than light?
Schneibster replied to kirbsrob's topic in Astronomy and Cosmology
I asked it twice in post 75. What "claim" are you talking about? OK, now we're getting somewhere. Do you deny that the Dirac field is explicitly Lorentz symmetric, i.e. incorporates special relativity? -
Why can't we go faster than light?
Schneibster replied to kirbsrob's topic in Astronomy and Cosmology
I'm no physicist. Can't you do that? I note you avoided my question. I'll try each point in turn instead. Do you deny that the Higgs field determines the rest mass that is an input to the Dirac field equations of the fermion field, through Yukawa coupling of the two fields?