Capiert

In physics, mass is a property of a physical body. It is the measure of an object's resistance to acceleration (a change in its state of motion) when a net force is applied.[1] It also determines the strength of its mutual gravitational attraction to other bodies. The basic SI unit of mass is the kilogram (kg).-Wiki https://en.m.wikipedia.org/wiki/Mass

I don't doubt he is telling standard physics.

Yes, ?, please continue. Please explain.You gave us a rooted (energy) equation, modelled perhaps?

As far as I know, the double slit experiment (results) confirms (or at least convinces me) light is a wave. Maybe a half wavelength could be interpretted as a (particlelike) impulse? ? Impulse? That's wild, & blows mine too.Some of the professionals will have to comment there, I don't know that new background. I prefer Maxwell's Ether opinion, too. Yes, variety is the spice of life, see that you don't suffer (integestion, heartburn) from too much spice (=new changes).

Moment (=stop please).Isn't (at the speed of light, c,) light standing still wrt to the other photons? (E.g. those photons going in the same direction wrt the earth.) Isn't speed c also a reference frame? What do you mean by shortcut? Please explain (a bit). ~Particles with [non zero] rest-mass, can be accelerated & deaccelerated, etc. What is the etc? (constant speed?)

Please proceede. Explain a bit (if you want). I agree, imagination & that we can understand is the hard(est )core to connecting & making sense of things. E.g. We do not write these threads for machines; they are written that people will understand, particularly the 1's asking. I find that most relevant. (Good that you pointed that out: Ridgidly relevant, (I like that).)

10-27 eV/(c^2) is mighty small, (I must admit); but if it (=the photon mass) lies at e.g. 10-32 eV/(c^2) then we will not know till we can achieve (better than) that precision.

..(photon suppose to have mass).Only the basics physics m=mom/c of the photon's momentum mom per light's_speed c; but we have to dissect Swansont's presentation to get to the bottom of it. In my book (=opinion, perspective) mass m=F/a is a coefficient (effect) for the rate of (inverse) acceleration (in Newton's force equation). Both F & m are virtual but you have made something of it (=mass) which you do not define further except as a thing. In German mass is a measurement of length, perhaps applying to the "inverse" of your mass_spectrometer's (electro)magnetic deflection (distance). But we know momentum mom=m*v. I cannot imagine momentum without a (physical) mass m (& speed v). That is its definition, or should I ignore that? Would you please explain that exclusion method a bit?I'm not clear yet. E.g. What fraction of an electron's mass do you anticipate (=assume) the photon's mass should be? (To get anywhere near into the correct range.)

It seems opinions are changing.What was said in the past is not true now. (What a mess.) Is it possible we don't have enough accuracy yet?

I tend to agree with you. Ignoring the slightest, is no excuse for denial.

How did you get the momentum?

You know that, the medium speed is c. m=mom/c m~8.5*(10^28) [kg* m/s]/(2.97*(10^8) m/s), at 780 nm, according to you.

There is no such (physical) thing as a zero mass particle, because that (so called) thing is a figment of your imagination (=fantasy, science_friction)! A photon has mass (no matter how small it is) because it has momentum mom=m*v. If a particle does NOT have mass (at all) then it does NOT exist, & is only a virtual (hypothetical) point (created by you, as a man_made fantasy) (with zero dimensions). (Otherwise we could call it (at least) a phenomena because it is happening with real (physical) mass.) Any wave, is carried by a (massive) medium (=mass), so mass must be involved. What makes you think otherwise? (Massless particle? that's like saying military intelligence, they don't intersect. Is destruction intelligent? You are implying a "zero" mass particle (with (the word) "massless") but everyone knows "less" still means it has mass, instead of none at all. So it's rediculous to claim a photon has no mass. E.g. You've approximated, & rounded to zero. Is that the truth?) (Charge can NOT exist without mass, it's always a mass to charge ratio.)

Is it really? I've seen the formula n0 = p+ + e- + 0.766 MeV (anti_neutrino). An electron is 0.511 MeV. (Energy, mass equivalence.) Now, take a neutron's mass, subtract a proton's mass, and multiply by c. That's how much momentum is released in the beta decay of a neutron. (?) (No!, doesn't fit because you ignored the proton's recoil.) (But that's no problem: opposite & equal reaction (Newton's 3rd law) says it (=the total (released momentum)) must be double (the electron's (released) momentum). What's the difference between Einstein's rest mass energy E=m*(c^2) formula & KE~m*(v^2)/2, using v=c? Answer: the half. E.g. (My) speed energy SE=2*KE (definition=substitution).)

Please explain. (Perhaps you are saying a particle cannot go at light speed, so the (newly released) Beta particle cannot (begin at c, (from the Coulomb charge repulsion) to) slow down from light speed via collisions to (e.g.) ~0.98*c; & the proton's speed would be much slower (in the opposite direction) from the recoil.) Thanks for the links. But each (small) particle decayed (or thrown off, e.g. mom1=m1*v1, using small syntax number 1 for simplicity, smallest) will have its own appropriate "deficit" (-2*mom1*mom2) depending on its own mass (m1), the (larger) partner daughter product mom2=m2*v2 & (largest=) original parent mom3=mom1+mom2. (Largest number, of the 3.) Thus your variety of (so_called) neutrinos. The important thing is, something is suppose to be missing if we add terms (of the equation's squared sides).

When I calculate neutron decay, into proton & electron using momentum & starting (both e & p) with light speed c instead of (the neutron's) 0 m/s, then I get a mass deficit of 2 electron masses instead 3/2=1.5 electrons, e.g. what you call an anti_neutrino. Please show me a neutrino "particle" that you claim to have discovered, I've never seen 1.

When I calculate neutron decay, into proton & electron using momentum & starting (both) with light speed c instead of (the neutron's) 0 m/s, then I get a mass deficit of 2 electron masses instead 3/2=1.5 electrons, e.g. what you call an anti_neutrino. Please show me a neutrino "particle" that you claim to have discovered, I've never seen 1.

When I calculate neutron decay, into proton & electron using momentum & starting with light speed c instead of 0 m/s, then I get a mass deficit of 2 electron masses instead 3/2=1.5 electrons, e.g. what you call an anti_neutrino. Please show me a neutrino "particle" that you claim to have discovered, I've never seen 1.

Very good.

Very good, some (kind of an) amount of momentum, so the unit must have time in it as you said. Yes & it's useful to look at it's (strengths &) weakness, with comparisons.

Please explain.Can we not recalibrate, starting with Hydrogen's light? (E.g. Starting from scratch.) Is the cloth so whole?Didn't Leibnitz's vis viva (~KE) do that with Newton's? (m*v, momentum, confirms the 1st law: constant speed v of a mass m; mom=F*t, confirms the 2nd law: acted on by a force F, for a duration time t.) Does it really?How then do you explain dark (=unknown) energy & dark mass? (=(unexpected) Problems?) Haven't you swapped your priorities biasing (=basing) everything (now) on energy, instead of (originally) momentum? Relativity, Quantum mechanics, gyromagnetic ratio, Higg's boson (was not predicted correctly), dark matter & dark energy. (All had difficult births.) What will be next? (Anti_energy? =my attitude.) It looks like the cloth is bursting at the seems. (Isn't the complexity increasing, instead of decreasing (to unification) for the patchwork cloth (you're mending, =trying to keep it sewed together, &) which constantly receives more patches=fixes=repairs?)

Momentumwise a wave('s amplitude) goes back & forth (up & down if you will) like bumping (bouncing) around. How do we know we are not dealing with light's (e.g. a photon's) momentum is mom=k*f where k is some tiny amount of a universal momentum? In other words the frequency f is a direct relation, & can be manipulated (=changed) with (extra) bumps (=bumping, bounces).

What is the formula for E?

Thanks for the excellent summary. Thank you also for pointing out my type error p, (I would have continued so without knowing because I use it so rarely).

Uh? Please explain. #12 You just stated before (#12 formula with rho), &#16 mv (=momentum) is used for photons; which are light speed particles (if I may say). Isn't moving at the speed of light also at least relativistic? If we use momentum to derive energy for the (relativistic speed) photon; but momentum is not correct (for relativistic (speed) particles) then our energy must also be NOT correct. (Why not then throw relativity & energy away?) Please explain.