Tim_Lou

it makes no sense that total kinetic energy of the universe is decreasing, 'cause that would violate the second law of thermodynamics... the temperature of the universe would decrease. Perhaps thats one of the reasons why an expanding universe is so troublesome.

i've read some wikipedia articles about masses... it says that mass is defined such that momentum is conserved. http://en.wikibooks.org/wiki/Special_Relativity:_Dynamics i found an excellent derivation of relativistic mass... before reading it, you should understand the general lorenz transformation in 3d. (the symbols ARE confusing... it took me quite a while to go through the whole thing)

i think perhaps if we discuss about the creation of a "particle" we might be able to figure something out. let's say...2 high energy photons interact, forming one electron and one positron. in terms of waves. what exactly happens when the 2 wave functions interact with each other creating a "discontinuity" in the electromagnetic field function. (also an impulse of gravitation field would results since "matters" suddenly appear) or let's look at the destruction of particles. let's say one electron and one positron collide, the gravitional field suddenly vanishes. (it should result in a "gravitional impulses" travelling outward). the electromagnetic fields become continuous and well-defined in all space and time.... well what exactly happens?

man, my job ain't fun at all..... i have to memorize all models of cell phones and price plans, policies. I haven't even memorize them all as of now. and people are constantly "battling" with you. With my boss trying to tell me to get more sells, and my customers trying to get cheaper deals..... these are all too... different from solving a... lets say physics problem... hehe

angular momentum a) relativity is based on [math]\vec{F}=\frac{d\vec{p}}{dt}[/math] so that momentum is conserved when there is no external force b) the concept of energy is never violated in relativity c) rest mass is a constant... so, its a constant d) in relativity, the position vector undergoes complicated transformation when switching frames of references. since angular momentun involves a cross product with the position vector, it is not generally conserved in relativity

perhaps you are thinking about the classical F=ma but in reality, the more fundamental equation is: [math]\vec{F}=\frac{d\vec{p}}{dt}[/math] and the thing is, according to relativity, an object with zero mass can have a non-zero momentum, since: [math]E^2=(mc^2)+(pc)^2[/math] if m is zero and E is non-zero, p must be non-zero. hence, the acceleration needs not be "infinite" when a "massless" particle is being "accelerated".

so how much is your first paycheck and how did you spend it? i took my family out for a nice dinner and saved the rest, as my sisters did. (well since im not much of a spender... don't know what i want to get/need)

relative to the center of mass: [math]R=R_1+R_2[/math] [math]mR_1=MR_2[/math] [math]R=R_1(1+\frac{m}{M})[/math] since [math]F=mv^2/R_1=mw^2R_1[/math] substitute...... it turns out that the first one is correct... perhaps you forgot to take the reference at the center of mass?

the thing is.... how complicated do you want it to be? mathematical wise? physics wise? equipment wise?

let's say we have a "photon", associated with an electromagnetic wave function. let's say this wave travels through a straight line, in the x direction. well, if we take a "look" just a little bit above that "wave function" (with a slightly different y-coordinate or z-coordinate), would the E/B field be non-zero? if so, wouldn't there be like infinite "numbers" of "photons". perhaps photons are just 3 dimensional disturbance of E/B fields. Well, what exactly makes one "photon", one "photon? maybe "one" photon can be defined as a "disturbance" of E/B fields with total energy one hf (integrating the energy density through the whole 3D space)? or a more general question, how must particle exists as integers? not 1.5, not 2.58323, not 0.2135446878647654... or as jay says, we will never know if particles are discrete or not..... to my understandings, the only way one can define a particle is through operations. If so then in an accelerated frame, it can be assume that gravity exists and a particle is causing it somewhere using general relativity and we should be able to interact with this imaginary particle (or mass)! if not then the equivalence principle is violated (am i missing something?)! i think this might be one of the problems GR faces.

and all massive particles are "excitations" in "gravitational" fields? so what exactly is this "excitation"?

perhaps the existence of a particle can be defined by gauss law? (neglect strong and weak force as i have no idea what the equations behind them are) as long as the surface integral of E field is non-zero, we say a charged particle exists within that region. or even better, using divergence (only for "density" though). (same for gravitational field) but then the definition of "fields" have to be re-written (so that it does not use a "test" particle)

Well, planck's energy distribution of black bodies can be derived perfectly from the assumption that energy exists in discrete packages. the only explaination for this is that photon is discrete particles, so that 1 energy package= 1-photon package, 2 enerage package= 2-photons package planck's finding really is mind boggling... I'm still trying to understand it fully... i read the above in a book from barnes 'n nobles, it shows the how planck first "accidently" derive it when trying to improve Wilhelm Wien's distribution, then comin up with a explaination to it....:) :hihi: nice free learning from barnes n' nobles. this has indeed shaken my understanding of continuum...it troubles me to think that one almost perfectly validated concept does not go with another almost perfectly validated concept... Anyway, how is electromagnetic field defined? another test "particle"... well the existence of photon must still rely on other "particles" regardless of whether not it is a particle... i think that something is missing regarding fundamental definitions here.

immortality... as a being, i would like to live. What else is there to do otherwise?

i have been thinking about this thing for a while. seeing how fields are always not well defined approaching the position of a particle, perhaps a particle can be defined as a discontinuity of field (any kind of force field) but then.... a photon, there is no discontinuity of electromagnetic field. perhaps this is something different. as I am not so good with quantum mechanics... knowing that position is not very well defined, the position of the "discontinuity" wouldn't be very well defined as well.... What other ways can a person detect/define a particle otherwise? besides observing severe distortion of force fields? hmm.... and how would a person observe a particle without another particle? if a particle is only well defined in relation with another particle, what does it mean?

i have to admit that i did learn a lot in the working places. during these couple of days, i made some pretty bad mistakes. Got my manager pretty mad. But i thought, "hey, deal with it Tim, where did your 'Tim-ness' go"? i kept doing my thing... and i was glad how i was able to cope with everything.

I got a job at a cell phone selling place recently..... gaining some real world experiences. I just wanna share my happines of my first paycheck--around 300 bucks. I have much less time thinking about physics and other stuffs... i don't know if it's good or bad though.

actually, things are the other way around. when we experience "fictitious" force, we know that we are being accelerated and in a non-inertial system. Now what exactly is the definition of fictitious force? i think there isn't a definition, fictitious force is as "real" as the other force. we simply put some gravitional fields in our equations and apply the GR eqations (please don't ask me how, 'cause i dont even know).

all particles. wavelength=h/momentum his hypothesis came from: [math]E^2=(pc)^2+(mc^2)^2[/math] for a photon, [math]E=hf=\frac{hc}{\lambda}[/math] [math]E=pc[/math] [math]\frac{hc}{\lambda}=pc[/math] [math]\lambda=\frac{h}{p}[/math] deBroglie hypothesized that perhaps this equation works for all things, not just photons. the diffraction pattern of electrons match his hypothesized.

E=mc^2 can be easily conceptualized with relativistic momentum without exact derivations involving some integrations. suspose a particle is moving at very close to c/2 and a force is applied for some time and it is now moving at very close to c. At another frame of reference moving in the direction opposite of the particle's direction, the initial velocity of the particle is almost c. the final velocity is also very close to c. the velocity increased very little (since nothing can travel passes the speed of light according to time dilation). in a classical mechanics sense, in the other frame of reference, the particle is like un-usually "heavy" so that the velocity changes very very little when a force is applied. Since the change in energy should be the same in both references (in a classical sense), somehow, the masses must contribute to the total energy.

after FIFA, there aint nothing to watch..... i spend more time in front of the computer than in front of the TV

electric field is defined as force per charge [math]\vec{F}/q[/math] if you place another charge near a charge, the "other" chrage will certainly experiences a force, the electric can be calculated as force divided by the charge of "the other charge" (assume the other charge has no effect on the first charge) before the unification of the two, magnetic and electric are considered as two separate things. magnetic field is definied as [math]\frac{F}{qv}[/math]. the direction of the field can be experimentally determined. the direction is the same as the direction of the compass if it is places at that location. So, magnetic field only excerts a force on a MOVING charge, not just any charge while a presence of a electric field will excert forces on any charge (be it positive or negative). to calculate force for electric field, one simply multiply the field E vector by charge, however, in a magnetic field, it is quite different. [math]\vec{F_b}=q\vec{v}\times{\vec{B}}[/math] here the cross product is used, this is experimentally determined back in the old days.

well, electric field lines always point away from positive charges direct toward negative charges. since electric field is defined as [math]\lim_{q\rightarrow 0}{\vec{F}/q}[/math] field lines do not mean much physically, it is just a visual interpretations of things. relatively speaking, field lines sort of represent "electric field density" (dont take it too literally). the closer the field lines are, the greater the electric field(magnitude). the thing is, lets say you have a positive charge and you want to draw the field lines around it. You can draw 10, 5, 20, or 100 field lines, it wouldn't matter, you will always end having having less field lines further away from the charge (lesser electric field magnitude). its just for visual interpretations. these field lines are good for understanding certain theories, like gauss's law. (the number of field lines going out an enclosed area - the number of fields lines going in this enclosed area are directly proportional to the charge enclosed--this is gauss law in terms of "field lines").

G, what is G? the gravity constant G? what do you mean by "gravity"? the gravitional field? if so, what is the direction of the field? what is the physical significance of G? how can it be measured to varify your equation? what is the definition of G besides [math]G=\frac{mc^2}{e.sv}[/math]? you said vortex but how would you define vortex? what is the mathematical description of it? what does it mean to be a vortex? your statements seem very vague and they lack any physical and mathematical support. Everything seems to be rhetoric talks. you need proofs to what seems to be "obvious". otherwise, I can just say "this is obviously wrong". if you are incooperating relativity and/or string theory, then incooperate the mathematics. words prove little in physics, show us some mathematical derivations of things. "3D space is compressed into the vortex" where does this idea come from? what "vortex" are you talking about? mathematically? "negative and positive pressure" what do you mean by postive and negative, mathematically? "3D spatial volume vaccum is energy" how come? where is it derived? i might seem critical but there needs to be solid justifications of things you said.

mass is a variable in the equation, and all others are constants. now if what you say is true, then all particles, no all systems will have the exact same mass because G is constant, which is not quite possible since mass is certainly a variable.