...believe it or not.They do have the mass of movement.Ask any expert for astrophysics,if you want too.When photons don't move,they don't have mass. They have discovered that photon irradiates 2eV,which means it must have mass.And they also told me that everything falls into a black hole because of everything has mass. Please,comment this,but really anyone I have asked,and anyone that studies astrophysics will tell you that photon has the mass of movement.
This is true, since stationary photons don't exist, and nonexistent objects certainly don't have mass. This may be true for an old-timer astrophysicist who is clinging to the now deprecated notion of relativistic mass. Nowadays, mass is defined as frame invariant, and it can be proven mathematically that photons have zero mass.
I contemplated this one from another angle a few months back. Firstly look (not directly) at a light bulb with a filliment when it's on, and ask your self "Where are the photons coming from?". It's obviously from the energy, however it's not taking any mass from the filliment or bulb as there would be nothing left. This suggested to me that a Photon, Doesn't actually exist and is just a pure waveformation that emerges from the filliment. I then extrapolated perhaps the photon exists (If seen by the correct equipment) as preportionally a waveformation Shudder, where a photon itself is like taking a rope by one end shaking it so it creates a wave effect down the rope, where the wave that seems to start from the end your shaking is the wave that moves down the rope and I believed that a photon could kind of be like that, but shifting through spacetime in a similar way. This would explain why it has no Zero-rest mass, because it's relationship to the universe would be flattened.
Nope, photons have no mass. You're messing up mass and momentum. Light has momentum; that is movement of mass, which photon's do have, even though they have no mass.
Well thats just making the matter more complicated! It is better defined as the product of energy and velocity.
What is the product of energy and velocity? Energy has units: M - L ^2/ T^2. (M = mass, L = length, T = time) Velocity has units: L/T. The product would have units: M-L^3/T^3. What kind of a physical quantity is this? Momentum is M-L/T.
StryderUnknown Try answering some of the questions in this thread. Many things are unknown to u. http://www.sciforums.com/showthread.php?t=38273
Gravage: Physicists never use the term "mass of movement". Perhaps you mean "momentum". Photons certainly have momentum, but momentum is not the same as mass. Photons also have energy, but energy is not mass either. A common argument made by people who don't really understand physics too well is that because E=mc<sup>2</sup> and photons have energy, they must have mass. What this misses is that Einstein's equation does not actually apply to photons in the form given here. For photons m=0. I don't understand what you mean when you say photons "irradiate" 2eV. Perhaps you can explain that for me. Photons fall into black holes because their trajectories are bent by the gravity of the hole. But, according to general relativity, that does not require that photons have mass.
Yes I knew some argumentative idiot would say this Please Register or Log in to view the hidden image! I decided not to complicate it but if u want the full definition then I meant it should be described as the product of rest energy and velocity!
The product of any kind of energy and any kind of velocity has the units M-L^3/T^3. Momentum has the units M-L/T. Hence momentum can never be the product of any kind of energy and velocity. It is mathematically impossible. It's like saying that my car weighs 3 seconds. Seconds are simply not a unit of weight, and no one who has passed even one high school Physics class would ever make this kind of mistake.
Of course you are right but I would like to mention that sometimes, when you have a physical law that connect two physical quantities with different units by just a constant factor, those different quantities are the same even though their dimensions are different. For example, in relativity, instead of taking the time as the fourth dimension, you can take as fourth dimension c times time (ct) which has a unit of length. However, if you use units where c = 1, then, you measure time in units of length. The same way, because of the relation E = mc^2, mass and energy are the same, and again, if you use units where c = 1, mass will have the dimension of energy. Last example is when you do quantum physics, you can use units wher h = 1 (h is Planck's constant). In this case, you see that momentum has dimension of 1/L.
Actually I just looked back to see how this all started and Shofftsa said momentum can be described as movement of mass. I shouldn't have said "product" because that implies a complete equation which I know is wrong. I meant to correct him and say that momentum is better described as movement of energy since something does not need mass to have energy.
Well, it would be a less-used quantity ALSO describing momentum in terms of energy rather than the standard mass Please Register or Log in to view the hidden image!
I'm a biologist(ish) but everyone knows mass = energy. I can't say I understand it, but if you believe that then obviously photons have mass. Their path is affected by black holes, indicating it has mass which gravity can act upon. No sources, sorry. (Any A-Level/High school physics text book). Edit: Directed at no one in particular - Blue
You may wish to take into account the fact that 99.9% of the physicists in the world say that photons do not have mass. Photons are affected by black holes because they are affected by the curvature in space-time which constitutes a gravitational field. This does not require that they possess mass.
I have it on good authority that photons have zero mass at rest only. Since they always move at the speed of light they have mass. Source: my father, Maths MSc 2:1, Trinity College, Cambridge University. He went on to confuse me about zero duration as well.
Hum, The blackhole isn't something that <i>sucks</i> the light towards it...it just bends the space-time into a gravity well ...a passing photon is basically intertwined with the space-time framework and follows the shortest path. (i imagine that if there were a `bump` them then it would go round) Please Register or Log in to view the hidden image! The gravitational field not directly affects it I think the original poster said that the (photon energy) E ≈2eV which is true; The <i>wavelength</i> of the photon has an energy equal to the electron rest mass... λc=(h/mc) (Compton wavelength) And we have to remember that momentum is a <b>vector quantity</b>, (which if the poster is right would then implies negative energy!). And i suppose that the collective energy of all the photons in the universe cancels out, by virtue of them being, er, messenger bosons. (Hehe, though I'm not proposing a new 'conservation of photons' law here ...) As for time: I think because the photon is travelling at light speed then... T[me] x /¯(1 - v<sup>2</sup>/c<sup>2</sup>) = T[photon] Where T[me] is my subjective time and T[photon] is the `subjective time of the photon, with v being the speed at which the object is travelling. So travelling at velocity c ( any direction), t[photon] = zero for every value of T[me] How a zero time reference affects energy I'm not too sure about... Perhaps someone else can expand.
A degree in mathematics does not qualify one as a physicist. What is the meaning, please, of the rest mass of an object which is never at rest??? From NASA at: http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961102.html "....while photons have no mass, they do possess momentum"
Although his academic qualification is in maths his work was more physics realted, but perhaps he's wrong or perhaps he meant something. I will challenge him about the article, if he churns something out I'll be sure reply. Just because something does not stop doesn't mean you can't calculate its resting mass. I think I'm going to have to step out of this one as I'm only parotting what others have said and have no relevant knowledge.
