I simply replied with a silly sentence to your silly remark
" a photon at rest ? "
I dont know whether for a native english speaker the expressions "mass at rest " and "rest mass" sound completely diffrent
For me it is the same stuff
I suppose that nobody on the surface of the earth think that you can stop the light ,thus I found your comment a useless little provokation
Yet the term "rest mass" even for a photon is widely used in scientific literature ( ex wikipedia )
Why not simply : "a photon has no mass ", then ?
If some authors emphasized the term "rest" even for a photon there is a reason , I suppose

This is the point , I was expecting your comment while you are asking again the same question

Not to mention that I myself said that in modern quantum physics photon is considered a massless particle
I said "The scenario has changed again.."
Also I said that the mass in the Einstein's equation must be understood as the rest mass
Please read the other people post too,besides reminding the others to read yours

Anyway the discussion was about a possible interpretation of energy and matter

I supposed that it is more interesting to go through the evolution of these concepts in the hystory of physics rather than jumping straight away to the standard model
It is true that the "kinetic" mass in general , as well as the one of the photon is not considerd anymore a , so to speak , "true" mass but is not necessary to evoke the standard model
Yet, it is also out of discussion that photons share with material particles many "massive" properties
If the photon of light push away ( together with the solar wind) the tail of the comet which are made of thin fragment of ice, well I dont think it is an heresy to claim that a stream of photons is somehow similar to a stream of material particles, such as, in this example, the solar wind

Thus the difference between matter and energy is not that sharp as scientits assumed before the great revolution in physics at the beginning of the 20th century and as many people still assume nowadays