timo

I know it´s a bit nitpicking (don´t get me wrong, it was a nice post of yours) but since you´re semi-quoting me with things I didn´t say let me add this minor correction: The "between two charged plates"-scenario is not the only one in which the intensity of the electric field remains constant.

In general, it isn´t. You probably have a specific field configuration in mind or mistook the results of a specific field configuration for being true in general.

The observer is simply someone who sits around and watches two light beams aproach each other (a third entity if you wish to see it like that). What might have confused you is that in this case "watching an object" does not mean that some light emitted from that object hits your eye but that the object has the respective coordinates in the observers frame or reference. The additional problem that to visually see something it must emit light which must reach your eye is usually not considered in relativistic toy-problems like this one.

For people wanting to give that information there is a field in the user description (something like "Academic Degree"). I think it is a good idea filling that in if one tends to ask questions. It might help getting more "fitting" answers.

That´s probably because he tried to exclude everyone who had similar interests .

Just to add: It´s not only cosmic neutrinos for which one goes underground for measuring them. Some attempts to find WIMPs (= weakly interacting massive particles, a new fundamental particle proposed by some exotic physics scenarios and a potential candidate for being dark matter) exerimentally also benefit from being placed underground to reduce background radiation. Seeing that Swansont and Martin both gave some links I don´t want to look cheap so I dug out at least one (not the experiment I was actually looking for but a similiar one) : http://edelweiss.in2p3.fr/index_newe.html EDIT: They also link to the other experiments on above site: http://edelweiss.in2p3.fr/pub/fichiers/autres.html . I was initially looking for CDMS as I´ve heard a few talks about it, lately.

Thanks to Tartaglia and expecially MattC for the answers. It was mostly the fact that I initially thought it might be magnetic resonance (tomography) but that no one commented on whether it is or not (all posters just wrote "NMR", too) - in fact, it was the "N" that confused me because I somehow thought of "N=nano" which didn´t make any sense.

Seeing that a surprisingly large number of people in here seem to know what "NMR" is, let me take the risk of souding stupid: What is "NMR" ?

I can´t really help you there but your chances of getting a usefull answer might be higher if you elaborated a bit on your question and what you are talking about. Examples: - What is NMR and NOE ? Perhaps someone who is not familiar with the apprevations still knows a bit about the subject. - Same goes for the term J-coupling (what is "J"? Coupling between what?). With all my non-knowledge about the topic I´ve shown above, let me at least try to give some direct help, even if it´s only a guess: Assuming NMR is what I know as "magnetic resonance tomography" then I would further assume that proton and carbon methods are two different modes that are sensitive to the respective material: Protons (=water) or carbon (err... bones?). The two substances probably (I´m still guessing) have a different resonance frequency so by chosing an appropriate frequency for the outer magnetic field you can get sensitive to the material you want to investigate (make a picture of).

I think inflation is the opposite of that.

I would have expected that IMM will quickly put an end to the admin-only porno collection.

Speaking for me I thought it was a harmless answer. I made my point clear that I don´t particularly like signatures. Why we are arguing? Because it´s possible that someone convinces the admins to increase the signature size. Be it for some fundamental reason or simply because a majority of people wants that. Within this scenario, I think it´s only fair to state that I don´t want it. -> Username, user profile This is exactly the reason why I compared signatures to adverts. -> user profile

Who reads signatures, anyways? Avatars are fine, you can realize who´s writing much faster than if you had to read the username (optimizing on a sub-second scale - now, am I lazy or am I damn lazy?). But signatures? For me they are just like adverts: "Information", but not the one why I am reading the thread / visiting the site. And usually completely irrelevant to the topic at hand.

You´re right except for Frankfurt which actually isn´t that big. The biggest cities in germany are: Berlin: ~ 3 million people Hamburg: ~ 1.7 million Munich: ~ 1.3 million Frankfurt is only ~ 650k. I´m pretty sure Cologne has more inhabitants, other cities possibly too. EDIT: Thx for the link ecoli. I had supposed that the US cities are bigger but it seems that was just (wrong) intuition.

It probalby means that he doesn´t know what a baryon is

I am not completely sure how to interpret your question. You mean "why?" in what sense? In the sense that the answer is something like "little green gremlins that feed on mass pull other mass closer to feed their hunger"? Physics boils down to being able to calculate processes not to give explanation in above sense. So mathematical descriptions are all that you get in physics. My standpoint is that more than that is even impossible to obtain for I think that human understanding of "this is how it works" cannot go beyond the "this model works"-level. By that I mean that if you have two completely different explanations for every possible experiment which both give correct predictions on the outcome you cannot tell which explanation is the correct one. In fact, I personally go as far as to consider things like force, potential, ... to be human-made terms, not reality. Of course but that´s completely normal. Gas has mass. ??? The force F exerted on a mass M at position x from a set of humans, each with mass m_i, at positions p_i is [math] \vec F(\vec x) = \sum_i \vec F_i(\vec x) [/math], where [math]\vec F_i(\vec x) = G \frac{M m_i}{\| \vec x - \vec p_i \|^3} (\vec p_i - \vec x) [/math] is the force exerted by human number i. Disclaimer: Above reply is about classical newtonian gravity. There are conceptual deviations in relativity but I had the feeling that newtonian gravity is more than enough here.

Well that´s what uncertainty is about. That you have two observables which you cannot find a common base of eigenstates for: If a system is in an eigenstate of operator 1 (e.g. after measurement of the associated observable) it is not in an eigenstate to op 2. Therefore, the value that will be measured for observable 2 is not clearly determined. On the level of matrix representation this simply means that both matrices cannot be diagonalized simultaneously.

What 5614 said does have to do with uncertainty in a way. For example, if you write down the projection matrix for a vertical polarisation and the projection matrix for ... say polarisation right-up, these two matrices do not commute which means that you cannot have both observables (quantum numbers) fixed.

I do not particularly like to introduce QM where it isn´t nessecary. I don´t know what "high school" is but it doesn´t sounds that someone in high school will be helped by being told that the example is a nice example of QM, especially not when the follow-up description is very vague. Stuff like a polarisation vector "up" and a polarisation vector "right-up" not being perpendicular (and therefore having a non-zero scalar product and a non-zero projection onto each other) is not unique to quantum mechanics but simple linear algebra. Admittedly, those LA properties directly transfer to QM which is based on LA to a large extend.

Tests for models with additional dimensions are far from being new. Whether astrophysical tests are something new of whether it´s just yet another testing idea I cannot tell.

But it´s bad for testing how to create a thread.

http://en.wikipedia.org/wiki/Calvin_cycle

Only grass with serious psychic problems does that.

Assuming you read my post, I´d like to know what was unclear there. I didn´t use uncertainty, my photons had a definite polarisation (x,y) and I didn´t use QM at any point (although admittedly the base-transformation used for filter 3 was heavily QM-inspired).

There´s absolutely no problem these two would have with each other. In fact, I attended a lecture on "Quantum Chaos" a few years ago - that was about the point when I lost my respect to call that chaos stuff a real science. The chaos-stuff in this sense is like statistical physics: You can do it for classical systems or for QM systems. No problem either way round. Yes, basically every theory sais that. Chaos theory is about that small inaccuracies in the knowledge of the initial conditions lead to huge inaccurancies in the prediction of the event within relatively small time. That´s correct if by "event" you are talking about classical (non-QM) ... err .. events. Most certainly QM. But as I said, the two don´t exclude each other.