timo

Sure. In the economists' perspective.

A lot of the apparently obvious problems with relativity mentioned in the OP could probably be resolved by actually knowing a bit about the topic. Didn't read the "Fresnel lens theory" part, so I cannot comment on that.

Okay, I see now. I understood the OP (and dapifo's 2nd post) completely different. I considered that all-bold question a rhetorical one, given the 2nd sentence, as well as (presumably) the links, give the answer to it.

I agree with the last two sentences with only a small extra comment, namely that they tested an additional part of the parameter space. But I neither get the implication of your first sentence nor the overall message you try to communicate. What is your point?

I'm not sure where you draw the line between "hypothesis" and "evidence". Other findings are considered as an evidence by some. A single experiment not finding evidence certainly does not rule out existence - it does at best rule out the particular parameters that were tested for. The motion of the hammock I currently lie in gives no evidence whatsoever about the existence of atoms, but that doesn't rule out that at a size much smaller than a thread matter is not a continuous substance, anymore. Btw.: mutliple exclamation marks in combination with bold font all-caps and a message of questionable intellectual value don't impress people.

I assume that "do we want a draft dodger as president" is a rhetorical question. But out of curiosity: how many people in the US would count not participating in the Vietnam war as a strength of character?

I'd go as far as to say that nothing weights significantly more than it does. That comment may seem like nitpicking to you. But perhaps you could also come to the conclusion that having a 2nd thought about what "wouldn't black holes weigh significantly more than they do" is supposed to actually mean (and the implicit assumptions that went into this statement) may lead to some insight by itself.

That doesn't exactly lead me to the conclusion that I need to grow up.

I didn't know that; considered it as more of a historical terminology, in fact (-> "photoelectric effect"). Judging from the index (looking for "wave-particle duality" and "duality, wave-particle") I could offer Merzbacher: Quantum Mechanic Schwabl: Quantum Mechanics Schwabl: Advanced Quantum Mechanics Bjoerken, Drell: Relativistic Quantum Mechanics Bjoerken, Drell: Relativistic Quantum Field Theory Weinberg: The Quantum Theory of Fields which happens to be all of the book I have at hand at the moment. That's admittedly only from looking into the index, not from reading through all of the books just to disprove your point (one may think that a central concept is listed in the index, though). I actually do have a chemistry book (Atkins: Physical Chemistry) that lists "wave-particle duality" in its index, though. Incidently, it happens to be from an author who was recently mentioned on sfn for making strange claims about physics.

Wherever one doubts the existence of Zombies, he should be shown this thread.

Being a scientist my knowledge about producing sound is naturally non-extensive - especially in a programming language I never used myself. Generally, for questions like "how do I do X in programming language Y", Google is an excellent source of information. For example, the very first google hit I got was http://www.daniweb.com/software-development/c/threads/57693/how-do-you-make-the-computer-speaker-beep-in-c , which looks promising for a start. Good luck!

Okay, I get your explanation now. I am not sure if that problem may specific to Windows, and at the moment I cannot look into it in detail (partly because I don't use Windows). However, my guess is that if you enter the answer "a" and hit enter, scanf will read "a", and then the next time it is called will read "\n". Try the following fix (as a blind guess; I am not a C programmer): scanf ("%c",&NOTE); /* old line you had in your code */ scanf ("%c",&A); /* add this new line exactly after the one above, to capture the "\n" character */ It's just a blind guess of mine, but try it out. Note that it's a nasty hack. Also note, that I am abusing the fact that you declared variables A,B,.. that are not used in the program. For proper code, define a proper variable. To make one more point for c++ related to your unused variables: Contrary to C, C++ allows to define variables where you need them, whereas in C you need to define them at the beginning of the function. So in C++ you could write char guess, cr_catch; scanf ("%c",&guess); scanf ("%c",&cr_catch); and have the definition of the variables and their usage at one place in the code (the definition at the beginning of the function could be removed in this case).

That doesn't make any sense to me. The answer is probably "no". I think you should delete the term "dimension" from your vocabulary and re-learn it with a proper definition (e.g. the above-mentioned "number of independent degrees of freedom"). Higgs bosons are something like "ripples in the Higgs field", so in that sense "yes". I'd like to point out that the translation (Higgs field, Higgs boson)<->(Electromagnetic field, photon) is not completely one-to-one in all aspects, though.

I don't understand your first problem. What does "the previous value of the 'note' variable runs the if function and a standard message is printed in the start of each try" mean? For the 2nd problem, you want to use a different data type to read the user input, namely a string or a "char*" rather than a char. However, my suggestion would be to use a C++ compiler and C++ data structures for your task (all of your code already compiles with a C++ compiler, so there is no need to start from scratch). In that case, your code would become something like // c++ includes and a "using" command you shouldn't bother about for now. #include <iostream> #include <string> using namespace std; ... do { // ask user for a guess. cout<<"\nFind the note (A to G): "; string guess; // "string" is the c++ datatype for texts. Oh, and I renamed it from "NOTE" to something that seemed more sensible to me. cin>>guess; // this reads a line from the input into the variable "guess". // note that you can compare to more than a single character. Also note that '' has been replaced with "" // also note the extra "|| guess=="do"" (or "mi", or "fa", or whatever would be appropriate). if (guess == "A" || guess == "a" || guess=="do") note = 6; else if (guess == "B" || guess == "b") ... else if (guess == "S" || guess == "s") { truetimes = tries - 1; cout<<"\nYou tried "<<truetimes<<" times" // I replaced the C output with C++ output. Strictly speaking there is, however, no need to do so. <<"You made "<<errors<<" errors"<<endl; system("pause"); return 0; } else { cout<<"cannot make sense of guess "<<guess<<". Please repeat guess."<<endl; continue; } if (note!=truenote) { cout<<"Try again!"<<endl; errors += 1; } } while (note!=truenote); // keep guessing until the guess was correct. It is of course not necessary to use C++ code, your issue can be solved in C, too. I would, however, strongly recommend using a C++ compiler and C++ datatypes for C programming. It offers a lot of nice extras "for free" without forcing you to actually program C++ (e.g. you can still ignore object orientation or arbitrarily many aspects of the C++ standard library).

The Bose-Einstein condensate (BEC) consists of bosonic particles. That can in fact also encompass matter. Typically, one uses certain atoms for realizing a BEC. Wikipedia says in this context that So according to above, photons have also been used (though that does sound way less impressive to me, at least at first). Gluons would be problematic: The theory of BECs does not consider a possible interaction between the particles forming the condensate, whereas gluons interact strongly.

More smileys ! I didn't know we had extra smileys that are hidden until you click "show all" .

I don't even know what "there was group of students who were answering to mathematics sums of high end mathematics questions without refering to rough calculations nor to any arithmetic calci" is supposed to mean. Of course, trained mathematicians can answer some mathematical some problems quickly that take untrained people using more basic methods ages to answer.

You presumably meant "QED", not "QCD". The simplified answer to your question is "yes".

No one posted an equation so far, and it is not clear what "the numbers" (which apparently cannot be exact) are supposed to be. Try rephrasing your issue with proper, grammatically correct sentences, and perhaps also proof-read your post before submitting. No offense intended, but some people trying to answer you put some effort into that, so I think you should at least put a fraction of that effort into the formulation of your question in the first place. To answer what may have been your question: There is formally an infinite number of possibilities for an electron and a positron to annihilate into two photons. In the center-of-mass frame, the two resulting photons have to have opposite momenta, such that the total momentum is zero. However, this anti-parallel pair of photons can still point into every possible direction in space.

An electron-positron annihilation must release at least two photons (assuming nothing else than photons comes out of the reaction). A single photon cannot satisfy conservation of momentum and energy simultaneously (*). Any number of resulting photons >=2 is possible for the same reasons as in the case of two incoming photons. But if I remember correctly, then at least for accessible collision energies 2 photons is the most probable outcome, with the probability rapidly dropping for each additional photon to be produced. (*): In the center-of-mass frame, the total momentum is zero, whereas the energy is at least two times the mass of an electron. Since for a single photon, energy and magnitude of momentum are directly proportional, a single photon cannot satisfy the two constraints of zero momentum and non-zero energy at the same time.

An anti-photon has no features distinguishing it from a photon (or alternatively: there is no such thing as an anti-photon). In principle, the reaction of two photons into N photons (and nothing else) should be possible for all N>=2 at one-loop level. In practice, two electromagnetic wave packets meeting each other (which is what you probably meant by "colliding photons") will just ignore each other - at least in vacuum.

Several - a possible correlation between the social and intellectual skills displayed by such a humble and well thought-through statement to the negative votes you receive being one of them.

Yet, the overall reputation of pretty much every long-term forum member is positive.

So you are the ominous .

That may just have been the first time that I understood what these magic words "ad hominem" (that I read in this forum for years, now) actually mean. Nice explanation.