You are using an incomplete equation. E=mc2 is the simplified equation for objects at rest relative to the observer. Obviously this is inapplicable to photons. The full version you should be using is E2=(mc2)2 + p2c2*. Since m=0 for photons, this reduces toE=pc. So stop trying to apply E=mc2 to photons. It’s wrong and will give you misleading ideas. * I can’t do superscripts on the device I am using. Please read E2 as E squared etc.
We know that in physical objects it's the mass of the object that is responsive to gravity. What then is the property of energy that makes it responsive to gravity? Energetic mass? From quora; Arinloye Sam Adebisi B.Sc Earth Science & Earth Physics, Federal University of Technology Akure (2013) Answered January 26, 2017 https://www.quora.com/Mass-has-two-...ted-by-gravity-and-occupies-space-Is-it-right
Why is it so hard for you to just accept that the umbrella that covers those things that affect gravity has expended to include energy? There simply is no reason that you have to cram the word "mass" in there somehow.
OK, I accept that. But then what is it in energy that responds to gravitation? It is a legitimate question.
No we don't we know that the stress energy is the source of gravity and all objects are affected by it full stop. In GR there is no aspect of an object that makes it responsive to gravity all objects must be because otherwise that would allow for something that didn't respond to gravity and then we couldn't use a geometric model.
Energy has a value. So has height and width and electric charge and many other things so if value is the only requirement for a thing to be subject to gravitation then almost anything should be. Or to put it another way you are doing your usual thing of trying to deflect a question you can't answer.
Something with a value that responds to gravity. https://www.sciencedirect.com/science/article/pii/S2211379719330943# I am not talking about photons flying around. I am talking about what occurs when a photon hits a physical surface and with what kind of non-zero value.
Do you believe there are things that are not subject to gravity? Can you cite an example? Not at all. I am boring in on the pertinent questions why light is responsive to gravitation if it has no value that can be acted upon. You are deflecting because you cannot explain what you posit. At least I am asking the question. So far I have not received a satisfactory answer except repetition of the same claim. I am waiting for your response, because you are the one making claims without supporting science. OTOH, I have produced supporting articles from reliable sources for my probing propositions. Just picked up a new term for me. "Radiation pressure" Can anyone explain how that occurs?
So it's a circularly defined term with no connection to reality I see. So what? Light in media travels at less than c and there it has mass as I've already said.
Of course not but you seemed to be claiming that a nonzero value of something was all that was required for a gravitational effect and a zero value of something was all that was required for no gravitational effects so I was just pointing out the absurdity of that. But the point of a geometric theory is that everything obeys the geometry it doesn't need a "value that can be acted on" because how can something not obey the laws of geometry? You are trying to make light fit into a Newtonian model of forces between masses and it won't work. You haven't asked for a source so far. See chapter 4 of Sean Carroll's lecture notes (https://www.preposterousuniverse.com/grnotes/) particularly equation 4.9 and the discussion between there and equation 4.22.
You did?! Oops,........ I must have missed it. Can you reference post#? On second thought, does that explain light in a vacuum being affected by gravitation? So far what I have is that everything is subject to gravitation, even if its value is zero. To me, that sound dubious. Haven't seen a paper on it yet, but I'll check out Sean Carroll.
From Sean Carroll Lecture Notes on General Relativity Gravitation ... ..... .... .... ... Gravitation due only to space-time curvature regardless of mass. Now we're getting somewhere. https://preposterousuniverse.com/wp-content/uploads/grnotes-four.pdf Still confusing. I just picked up these tid-bits from a cursory reading. I'll need more time to absorb the formal language. I like Sean Carroll! Thanks for the link.
http://www.sciforums.com/posts/3682376/ OK, we have mass of a photon with zero rest-mass when traveling at less than c in a medium. But traveling @ c in a vacuum the photon does not have mass? This is still confusing. Maybe reading Carroll I'll get a better perspective.
No we don't. No it isn't. \(m=\sqrt{|p^\mu p_\mu|}\) as I said. If \(p\) is null \(m\) is 0. If \(p\) is not null \(m\) is not 0. Light does not travel at c in media so its \(p\) is not null. In vacuum it is.
