Schneibster

No. Gravity travels at the speed of light, and if we can't see galaxies because they're moving faster than light, we also can't be affected by their gravity.

Actually the involvement of relativity in those cases is still explicit, but its values are all poles/zeroes. So t time equals tau time, mass equals rest mass, and length equals rest length. This seems an obvious place to define a zero frame: it's motionless. Here's the problem: there's nothing to make it motionless relative to. So this both works (your local frame to the observed object) but also doesn't work (what's "moving" mean?). Are we OK so far?

Through SR in the Dirac field of the fermions. The Higgs scalar field is invariant over velocity. It merely acts on the masses of the fermion fields. Since these masses are determined partly by SR when the velocity is nonzero, the Higgs field interacts with the relativistic mass. If I recall correctly. Later: also, Dirac fields are Lorentz invariant theories. So you were redundant.

Where did the CMBR come from, then? And how come it's the same in areas separated by 26 billion light years?

There is no requirement to create spacetime from anything. Since it's empty, i.e. nothing, it can be created from nothing. It's more correct to ask "what creates it," and the answer is the Casimir effect/cosmological constant/dark energy. Just as it pushes two plates together in the laboratory, it pushes space apart. And in answer to the OP, since spacetime is nothing, it's massless and can exceed the speed of light. Also there is an error in your question: we cannot see anything going faster than light. The point beyond which galaxies are receding faster than light is called the "horizon" and we can see nothing beyond it.

Mmmm, not quite sure that's entirely correct. Technically proper time is the time between two events measured on a clock that passes through the locations of the two events as each one happens. So not all inertial frames can measure proper time. If I understand "proper time" correctly. And the math says I do. michel, could you please answer my question in post 74?

So you're saying you can only measure the "true" length, mass/energy, and time from a frame that is comoving with what you observe? You're going the same place I did. I'm going to try leading michel step by step.

I think they're victims of Putin. It's just music. What's his problem? A bunch of crazy gggurls being rebellious teenagers can get to him that much? Boy, he's pretty weak.

They didn't figure that out for a while. When they did they started making them bigger.

You want to try to get a whole picture of the particle cloud from each collision, and so you layer the detectors so that the stuff that penetrates gets detected at the outside and the stuff that doesn't penetrate gets detected at the inside of the detector array. What's impressive is that we already know so much that the detectors are thirty feet tall! I have pictures of setups from the '40s and '50s and they're the size of your fist! Wilson Cloud Chambers. With a diaphragm to supersaturate the air just when the synchrotron beam goes through. Think of that now. HEP is so very gaudy and has so much sexy hardware. Fifteen tons of it is like some sort of erotic dream or something to someone like me.

The cascades of detectors, for all the different classes they want to look at, are many times the size of a human. That's probably the best answer, closest to answering the question you think you're asking, Genecks. ;D It's not the particles, it's all the different detectors we want to run them through. Because some of these particles are very elusive, their detectors have to be correspondingly physically large to increase their probability to detect them to something reasonable. In addition there is a minimum size for a given energy, dictated by the strength of the strongest magnetic fields we can make, which requires the accelerator track to be miles long; but the question remains, from the IP, "Why can't we put all the detectors on a chip even if we have to make the accelerator rings huge?" and that too is a valid question, and almost certainly of interest to everyone. Looking at the huge ATLAS detector for the LHC with a tiny human standing next to it makes the point; the beam is coming in a millimeter wide. Yet there are tens of meters of detection equipment. And this is as it should be. In fact, some of the particles that the LHC makes are sent through solid rock to a point many miles away in Italy, where there is a neutrino laboratory. The miles thick solid rock acts as a filter, leaving only the neutrinos on the end of the beamline.

You can sneak them in, but they always make weirdness, like the twin paradox and so forth.

Amusingly I find myself in a discussion with Bryce Rydow on Daily Banter about trolling at this time. Bryce is a political blogger, so his opinion may be of interest (and a certain amount of credibility, this being his area of expertise) here regarding trolling. He and I are discussing the definition of trolling and he has brought the Urban Dictionary (which is a Pretty Good Source for such things) definition of trolling: I have proposed that there is an element if not of dishonesty, at least of disregard for the truth, involved in trolling. It is this element of essential disregard for the facts that is, in my view, the signature of the true troll. And I believe this is missing from the above definition. The troll wishes to disrupt and during the disruption gain allies and co-disruptors. The troll is uninterested in the truth or otherwise of its assertions; the only measure of them is the disruption they cause. Their truth is irrelevant. This is the worst characteristic of the troll. I have also noted that lately (i.e. this century), trolling is no longer a male monopoly. As many women as men are willing to troll, in my experience. Errr, yay trolling gurgle. I'm totally in favor of equal rights, but I'm not in favor of anyone being an asshole, no matter what their rights are.

Don't feel bad, I remember the time three of us designed an encryption scheme that would reduce anything to one bit. It was for "write only memory." 8D

There's another reactor design concept that's got some advantages similar to pebble bed reactors: Traveling Wave Reactors or TWRs. These have the advantage that they burn up everything radioactive and leave cold, radiologically inert (though potentially requiring chemical treatment) waste. So they're also more efficient, i.e. more kilowatts per kilogram of fuel. First, they are non-proliferating since there's nothing left when they're done burning the fuel; second, they cannot melt down; and there are many other advantages. In other words, we've solved this trick two ways. I disagree with some of the statements about the various accidents, and also point out that the problems at TMI, Fukushima, and Chernobyl were not in any way similar, nor were any of them similar to several other accidents that weren't mentioned. There's a lot to be discussed, and some of it is in the political realm; from an engineering point of view, however, it's more a matter of going and doing it than inventing anything we don't already know how to do. And this is a discussion that is becoming more crucial by the day as we continue to watch India and China build coal power plants.

Such errors are not uncommon (though fairly rare) in textbooks. I remember a problematic claim I found in one of my transistor theory textbooks that had the Dean of the electronics school shaking his head. I can think of perhaps one or two other times I've seen something like that. You're smart to have spotted it. Keep watching, it's a good habit.

What makes you think it was a "single point?" It was a vacuum fluctuation. That's small, but it's not a single point; and it instantaneously began expanding, and in 10-43 of a second (not 1/43; in fact, less than a billionth of a billionth of a billionth of a billionth of a billionth of a billionth of a second), the inflaton-- that is, the cosmological constant, or the Casimir force, or vacuum energy, or zero point energy, or lambda, they're all the same thing-- underwent vacuum decay, and all of its energy was dumped into the newly formed universe and made the Big Bang. Obviously the vacuum fluctuation was bigger than 10-43 light seconds (that same billionth of a... sequence minus one "billionth," of a foot; something on the order of a Planck length, IOW). As a result, locations on opposite sides of the universe have never been in causal contact. However, locations on opposite horizons are not "opposite sides of the universe," even if the universe is the smallest it can be given the other evidence we have of its size. In fact the largest the horizon can be is about 2/7 of the diameter of the minimum possible universe right now; that will change over time. Incidentally that's not a very good description of the reasons for the addition of inflation theory to the Standard Model, ΛCDM. There are quite a few (I think ten or more) reasons for it, and most recently we've seen gravity waves it predicted in the CMBR. But we can get into that later. Let's get each of your questions answered first. Actually, the universe is remarkably homogenous (symmetric). We are only beginning to detect asymmetries at the ten-billion-light-year scale, for example the Great Wall in Hercules. The answer is, inflation expanded the sizes of tiny quantum fluctuations within the inflating universe from submicroscopic to that ten-billion-light-year scale. These quantum fluctuations also of course exist at scales down to the million light year scale, where clusters of galaxies have formed due to the compression of matter by gravity. So the reasons for these asymmetries are similar, but on vastly different scales. Do you have some other definition of "asymmetry" that you'd like to present? The galaxies near the horizon would behave differently than they do if there were no other galaxies beyond them. There isn't any more light coming from anywhere beyond anything; expansion is now accelerating and every year we can see a light year farther, but all the galaxies have moved out more than a light year. That's due to dark energy. There you go! Feel free to keep asking, I like answering questions like this, it exercises my knowledge and makes me look stuff up sometimes, which generally results in me getting smarter. Oh, and good questions! +1 for that. BTW if anyone wants real exact numbers, The primal vacuum fluctuation was on the close order of the Planck Length, 16 x 10-36 meters. Inflation is estimated to have finished by 10-43 seconds, by which time the universe was at least a hundred billion light years across. Inflation was stopped by vacuum decay. At this point, the cosmological constant (which, because it is not mass or energy can be freely created along with the creation of space; it is, in fact, the exponential feedback of increasing spacetime creating increasing cosmological constant creating increasing spacetime that results in the inflation in the first place and makes it so large so fast) dumps all its energy into the newly created empty spacetime. Wikipedia has a timeline; it wasn't accurate the last time I was there, they were still trying to put the inflation after the Big Bang.

Considering the electron jets from the quasar machine (which everyone pretty much figures is a young, active black hole) I'd be careful about making any blanket statements myself. It's not like we can go measure charge. A) we're too far away and B) seems like all the quasars have shut off. OTOH, I do have to agree that forming a black hole that has a charge could be impossible due to the point you've made. I think though that one getting a charge by some separation of charged moieties in the disk and/or jet processes after it already exists might be possible. As a speculation I wonder if it's possible to collect enough electric charge to make an electric singularity. Not on this thread though; let's stick to angular momentum hair.

I was fairly convinced when I saw the film of Andrei Linde quaffing champagne.

I'm pretty good with five plus sigma results. And they're a lot more significant than that, by now. I think with the latest data, that we've been discussing, finding the gravity wave signatures in the CMBR, it's pretty much over. It was still possible to argue against inflation before that. I don't think it is any more. It's too successful. I should note for all readers that inflation has gone from success to success and is currently making repeated predictions that are all coming out correct. I think the biggest question, davidivad, is whether the magnitude problem in the measured Casimir force with respect to the predictions of the magnitude of Λ are being resolved. That's always been the fly in the ointment.

You're living in the 1960s. The CMBR is the proof of the Big Bang. That dispute was history fifty years ago. Not to be disrespectful, but this is pretty disappointing. You're just dismissing evidence you've never seen. Sorry if I upset your applecart, but none of your claims hold water. At the end of your rant, you are dismissing relativity. Which is a hundred years old. C'mon, man, stop being silly. Nobody's lying to you here.

Basically that's Quantum Field Theory's point of view/interpretation of reality, right, davidivad? Second quantization leading to the field that is the probability function for all particles to interact with it at any given point?

Yes. However in the Cap'n's defense, it's a mistake we all make. And it does take infinite energy, so "infinitely close to the speed of light" makes colloquial sense, if not precise pedantic fussy accuracy. (Sorry, Cap'n, I assumed it was my mistake. I wasn't trying to be funny at your expense but at my own.)

There is a place where this gets hinky, but it's not the place you're thinking. It mostly has to do with the shape of a gravity field. A gravity field created by a mass is spherical. In real terms, this means, there is in fact an experiment that can tell you if you're accelerating or in a spherical gravity field. It's quite simple: as two objects at the same altitude fall in a real gravity field they move closer together. And this does not happen in an accelerating rocket. You will hear "local" used a lot; this is an acknowledgement of this real difference in the behavior of gravity and acceleration. The key point is, however, if you can imagine a planar instead of spherical gravity field, that planar field would, in fact, be completely indistinguishable from acceleration within the elevator. When relativists talk about a "local experiment," they mean one that doesn't cover enough volume to allow this difference to be measured. It is, BTW, more correct to say "acceleration due to the curvature of spacetime." However, that is a shot in the dark; I'm not entirely clear what you're objecting to so I'm quoting some doctrine that's similar to what I perceive you as talking about, but I'm not confident I'm really answering your questions. However, if I'm not, the above background is necessary to understand the correct answer anyway, so it's not wasted time. The car pushes you forward. This is a real force. You can also define matters (by using the frame in which the car is motionless and accelerates the Earth to its rear) in the opposite direction, and it is this that is called a "pseudo" or "fictitious" force; however, it is always (or, rather, it's components always add up to) Newton's Second Law, as modified by relativity. Later: One of the things that's always gotten my rear end beat by relativists is forgetting that motion and speed/velocity are relative, but acceleration is absolute. You can always perform a local experiment that will tell you if you are accelerating; you can never perform one that will tell you if you are moving.