elfmotat

In the case of trolling I agree that using the report button is probably for the best, but what about in the case of crackpottery, which happens much more frequently? AFAIK crackpottery in itself is not against the rules.

This is the only part I particularly disagree with. What about when the post in question really does contain trolling or crackpottery? Just ignore it and move on? Pretend we don't know what's going on? That seems counter-productive, if anything. "Trolling" and "crackpottery" are activities that people choose to engage in, not necessarily personality traits. There's nothing personal about attacking the content of a post, and there's nothing wrong with calling a spade a spade.

What's wrong with the Nichols-Hull experiments? You said yourself that, "test seems to fit to the theory." Indeed they confirm the radiation pressure predictions of classical electrodynamics to an accuracy of better than 1%. If you disagree with their conclusions then at least give a reason why. All you've said is that you disagree, for weird nebulous reasons.

Okay, so can you relate those equations to some sort of "gravitational bubble solution" to the EFE's? Just at first glance, the bubble frequency varies as a function of 1/R. It seems like you could probably relate bubble frequency to gravitational potential in some way.

I never said it was your invention, just that it was bogus. The video is also bogus. Apparently Pamela Gay is giving him and his audience the standard popsci treatment, where concepts are oversimplified to the point that they're practically meaningless. If you have any specific questions about relativity then feel free to ask them in the relativity section. I'm sure nobody would mind answering, as long as you don't ignore the answers you receive like you've been doing in this thread. There is no known "mechanism" by which a photon can be produced with no momentum. (Except for the trivial case of an infinite-wavelength photon.) If you want to invent one, go right ahead. Just know that it isn't going to agree with experiment. Go ahead and try if you want, really, nobody is going to stop you. When you're done, report back and we'll see if my prediction came true. As far as the "mechanism" behind photon production, it will probably help to think of photons as "really" being tiny wave-packets moving through a photon field. The photon field can interact with other fields, for example the electron field (or any charged field). Wave packets in the electron field can transfer some of their energy/momentum into wave packets in the photon field, and vice versa. However, the photon field is massless, so disturbances in the field will always propagate with velocity c. As for why photons carry energy/momentum, that's a bit like tossing a pebble into a pond, watching the waves it produces, and then wondering "why do the waves carry enery/momentum?"

A lot of us know relativity quite well, and we know when you're making bogus claims. Photons do not "experience" anything, because talking about what a photon would experience from its perspective is a nonsensical question. There is no physical meaning behind those words. Photons do not have a perspective. We can't use physics to describe scenarios that violate the laws of physics. This entire thread seems like a textbook example of an argument from personal incredulity. "I don't understand/believe it, so it can't be true!" With the exception of creationists and climate change deniers, rarely do I see people work so hard to deny evidence.

And this is the root of the problem. Vague, ill-defined philosophical questions.

Mike, you're putting us in the position of having to comment on something which isn't well-defined. We simply don't know what you mean by "spherical bubbles." It sounds an awful lot like a black hole, but apparently that's not what you're trying to describe. Classically a black hole can be arbitrarily small, and its properties are completely determined by its mass, electric charge, and angular momentum. This sounds directly analogous to the properties of elementary particles (ignoring weak and color charge), which is what prompts some people to think about whether elementary particles can be described as black holes. On the other hand, AFAIK nobody actually believes that particles are really black holes. As I said, this sounds an awful lot like a black hole. A BH with a mass energy as small as you describe would have an event horizon ~30 orders of magnitude smaller than the Planck length. They're explaining how Riemannian geometry is used for both soap bubbles and GR, not anything having to do with gravitational bubbles. This shouldn't be surprising either: Riemannian geometry is simply the geometry of curved spaces. The surface of a soap bubble is a 2D curved space. If you're wondering whether or not Riemannian geometry can be used to model electromagnetism (and therefore light), the answer is: yes, but with some issues. It was invented ~100 years ago, and is called Kaluza-Klein Theory. I'll give a quick explanation if you're curious: Basically, the entire theory of General Relativity can be boiled down to two equations: its Lagrangian and its equation of motion (the geodesic equation): [math]\mathcal{L}_{GR}=\sqrt{-g} \, R[/math] [math]m U^{\nu} \nabla_{\nu} U^{\mu} = 0[/math] where g is the determinant of the metric, R is the Ricci curvature scalar (which contains second derivatives of the metric), U is four-velocity and m is the mass of a test particle. The Einstein field equations (which determine the gravitational field) are derived from the Lagrangian, and the geodesic equation tells you how things move when there are no other forces present. Similarly, the entire theory of electromagnetism can be represented by two equations: its Lagrangian and its equation of motion (the Lorentz force law): [math]\mathcal{L}_{EM} = \frac{1}{4} \sqrt{-g} \, F^2[/math] [math]m U^\nu \nabla_\nu U^{\mu} = q U^{\sigma} F^{\mu}_{~\sigma}[/math] where F is the electromagnetic field and q is the charge of a test particle. Maxwell's equations are derived from the Lagrangian, and the Lorentz force law tells you how things move when only gravity and electromagnetism are present. Kaluza realized that if you postulate a tiny "curled-up" fifth spacial dimension, and if you construct the 5D metric in particular way, then something magical happens. By analogy with gravity in 4D, we define a 5D gravitational Lagrangian as: [math]\mathcal{L}= \sqrt{-\tilde{g}} \, \tilde{R}[/math] where the tildes above g and R denote that they are the 5D versions. The 5D metric is defined as: [math]\tilde{g}_{AB}=\begin{pmatrix} g_{\mu \nu}+\phi^2 A_\mu A_\nu & \phi A_\mu \\ \phi A_\nu & \phi \end{pmatrix}[/math] where the capital Roman indices run from 0 to 4, Greek indices run from 0 to 3, [math]g_{\mu \nu}[/math] is the usual 4D metric, [math]A_{\mu}[/math] is the electromagnetic potential, and [math]\phi[/math] is some constant (technically it's a scalar field). If you work out the determinant of the 5D metric, you find [math]\tilde{g}=g[/math]. If you work out the 5D Ricci scalar with this definition of the 5D metric, you find: [math]\tilde{R}=R+\frac{1}{4} F^2[/math] So the five-dimensional gravitational Lagrangian becomes: [math]\mathcal{L} = \sqrt{-g} \left (R + \frac{1}{4} F^2 \right ) = \mathcal{L}_{GR} + \mathcal{L}_{EM}[/math] Almost miraculously, 4D gravity + electromagnetism seems to pop right out of the definition of 5D gravity. Similarly, if we work out the 5D geodesic equation, we obtain the following two equations: [math]\xi \equiv U^4 + A_{\mu} U^{\mu} = const.[/math] [math]U^\nu \nabla_\nu U^{\mu} = \xi U^{\sigma} F^{\mu}_{~\sigma}[/math] The first equation tells us that there is some conserved quantity having to do with motion. The second equation looks startlingly familiar to the Lorentz force law. Indeed if we identify [math]\xi = q/m[/math] then the two become equivalent. Interestingly, this gives us a definition of electric charge: [math]q=mU^4 + mA_{\mu} U^{\mu}[/math] Since U4 is the velocity through the extra dimension, we associate charge with a particle's momentum through the extra dimension. Kaluza-Klein theory has a lot of problems though. For example: the size of the fifth dimension should be unstable, which should cause it to blow up and become macroscopic. It also predicts a so-far unobserved scalar field. The theory can't be made quantum mechanical either, because it includes General Relativity as-is. **Note that I've cheated a bit in places. For example I set [math]\phi=1[/math] for simplicity, and I've assumed the fifth dimension is too small to have a significant effect on the 4D motion of objects.

However there are physical scenarios where exactly the opposite is true. Past the event horizon of a black hole, the radial coordinate becomes timelike and the time component becomes spacelike. In other words, you can't stop getting closer to r=0 anymore than you can stop aging. Weird stuff happens with time too: you can quite literally see (as long as you're looking away from the singularity) events from both the past and the future. For example, if I jumped into a black hole, fell a distance of ~1 light-minute, then you jumped in after me, I would be able to see you from both one minute in the past and one minute in the future.

First of all, how do you know that's true? Lorentz symmetry may very well be an emergent symmetry that appears at large scales. It might be a fundamental symmetry, it might not, but you don't get to just make up an answer before we are able to do the tests. As of now it appears to be fundamental, but that might very well change. Second: even if Lorentz symmetry is fundamental, how does that show that "time is not physical"? I don't see the connection. And how are you defining physical? The usual definitions include something to the effect of "a measurable quantity." Time is a measurable quantity, so I would certainly define it as "physical." I don't say it's impossible, just that I don't know how to do it.** And apparently you don't either, because you keep giving circular definitions. **(Except, perhaps, by adding more time dimensions. But that certainly doesn't solve any problems in terms of defining what time is.) That seems like a vague philosophical question rather than a physical one. Well, that's just an unorthodox definition of the word "physical." It's generally a good idea to keep words' commonly understood definitions, otherwise you're going to be constantly redefining them and confusing your audience. Obviously. Causality is defined by a relationship in time. That would be circular. I'm not postulating anything. The only thing I've said in terms of time's definition is: "time is what's measured by clocks." You're making up some kind of weird hierarchy where some things are "more" physical than others. By any useful definition a thing has got to be either physical or not physical.

Says who? What are "LT" and "RT"? I don't see how any of what you said addresses any of what I said. All you've accomplished is a pedantic shift in vocabulary. You're doing it again. How can there be change with no time? Your reasoning and your definitions are circular. Worse, they're conceptually meaningless.

What solution of the field equations are you using to describe these "spherical bubble photons"? What sort of stress-energy allows for solutions of this type?

"Go slower" through what? You keep doing this - you're invoking the vocabulary of time in order to explain and define time. It's not helpful or enlightening. Essentially all you've done here is proclaim "change" as a synonym for "time." Neither. For you time passes normally.

I'm not really sure what you mean by "there is no access to time than through change." Because that sentence implies that these changes are happening over time. In other words, "there is no access to time than through change over time." That seems circular, and true by definition.

So is this a concession that your point is wrong? Swansont made a point: you can talk about fields having values at each point in space, even if no sources are around. Even if you get rid of the concept of sources altogether, nonzero vacuum solutions will typically be allowed for a given field. The point being that "fields" and "time" are useful abstractions we take to exist even when we aren't looking at them. (In fact, even if they are zero you could still argue that they are still "there.") For some unexplained reason you decided that the fact that some fields have sources is enough to do away with swansont's point. Rather than get bogged down by exactly why your objection makes no sense, I decided to cut through it by giving an example of a physical nonzero field without sources. I quite clearly never said anything that would even hint at the chronon idea. Whether or not time is quantized is irrelevant to the point I was making, and I'm sure you know that as well as I.

What in the world do field sources have to do with his point? If you insist on being pedantic, how about the Higgs field then? It's nonzero everywhere in space without sources.

Time is what's measured by clocks. Why does anyone bother with these useless semantic descriptions, like "time is an illusion," or "time is just change"? Why not ask how many angels can dance on the head of a pin while we're at it?

No it won't. That's not the way interactions work. You need to be able to reproduce the predictions of quantum electrodynamics with your theory if it is any good. That means that via perturbation theory the probability for interactions with charged particles to take place will depend on the fine structure constant. You need to explain where the fine structure constant dependence comes from, and why it doesn't include the gravitational constant G (where does the G-dependence of the gravitational field go?).

Mike, I still have no idea what a you mean by gravitational bubbles. You're using very vague language, which makes what you're saying hard to interpret. You also didn't address my other question: why do photons interact so strongly compared with gravitons, if they are both aspects of the gravitational field? Any gravitational theory you invoke will include Newton's constant G, which should always keep interactions very very weak. You would presumably need to add additional degrees of freedom to the field to get around this, which means you aren't even using General Relativity anymore.

What, precisely, do you mean by a "gravitational bubble?" You haven't explained this. Also, why, if photons are part of the gravitational field, do they interact so strongly compared with gravitons? This doesn't seem possible to reconcile.

It was my understanding that the negative mass2 at [math]\phi=0[/math] is just a way of saying that the field is not stable at this value. I don't believe you can get any "real" tachyon quanta from the theory.

I still don't know what that means. Tachyons are not allowed in modern field theory. Tachyons make possible causality violation, which is not something that you want in a sensible theory. Theories of scalar interacting tachyons have been worked out though.For example: http://journals.aps.org/pr/abstract/10.1103/PhysRev.174.1808 (You might need access to a university library to read it.) Saying "particles are wavepackets with energy" is not quite the same thing as saying "energy travels through particles via waves." The former makes sense. The latter doesn't. The peaks represent places where you're likely to find a particle. They are not by themselves particles. Any massless particle will travel at c. Photons, gravitons, gluons... What do you mean by "proportional change"? It seems quite vague. Wave functions cannot be measured at all. They're the square root of a probability distribution. So I'm still not quite sure what you mean. Well, you must have had some reason for mentioning it. I just don't see how it relates.

What is an "airgap"? What do you mean by "permeable... to energy transmission"? Energy does not "travel through particles via waves." Not all particles, other than photons, have mass. Gluons, for example. What do you mean by "measured by particle velocity"? What do you mean by "channel energy into mass-bound particles"? What do you mean by "mass-bound particles"? What do you mean by "excite exotic matter into measurability"? What do you mean by "2-way matter-energy processing bottleneck"? What does this have to do with the Higgs field? Sorry, but your post is pure gibberish. Please don't make up nonsensical jargon and pretend it has meaning.

I've noticed the same thing, which is why I don't usually bother people with science-related discussion unless they bring it up first. That, plus I learned when I was little that nobody likes a know-it-all, especially one that doesn't shut up.

Zero is a nice number. Slightly more than zero is not nice, and generally requires some kind of fine tuning. (This is why the slightly non-zero cosmological constant is so puzzling.) From a theoretical perspective massless photons are much nicer.