Relativity hypnotists wish to know why Einstein was silent about momentum and mass of the photon:

http://www.physicstoday.org/vol-59/iss-6/p11a.html [nofollow]Other hypnotists have provided the answer:

http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html [nofollow]"Einstein went on to discover a more general theory of relativity which explained gravity in terms of curved spacetime, and he talked about the speed of light changing in this new theory. In the 1920 book "Relativity: the special and general theory" he wrote: . . . according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity [. . .] cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position. Since Einstein talks of velocity (a vector quantity: speed with direction) rather than speed alone, it is not clear that he meant the speed will change, but the reference to special relativity suggests that he did mean so."

In other words, the speed of light can be 300000km/s in Position 1, 300001km/s in Position 2, 300002km/s in Position 3 etc. An even more informed hypnotist, Tom Roberts, explains further in sci.physics.relativity:

> Sam Wormley wrote:

> > Valev confuses *velocity* of light with *speed* of light!

> AFAIK Einstein basically thought in German, which does not have

> different words for "speed" and "velocity" ("die Geschwindigkeit" is

> used for both). Certainly his "velocity of propagation" could be phrased

> as "speed of propagation" without changing the underlying physics.

> Tom Roberts tjroberts@lucent.com

> Pentcho Valev wrote:

> > CAN THE SPEED OF LIGHT EXCEED 300000 km/s IN A GRAVITATIONAL FIELD?

> Sure, depending on the physical conditions of the measurement. It can

> also be less than "300000 km/s" (by which I assume you really mean the

> standard value for c). And this can happen even for an accelerated

> observer in a region without any significant gravitation (e.g. in

> Minkowski spacetime).

> Tom Roberts tjroberts@lucent.com

Note that the relevant problem is WHETHER THE SPEED OF LIGHT IS VARIABLE IN A GRAVITATIONAL FIELD, not whether the photon is massless. The variability of the speed of light in a gravitational field implies (through the application of the equivalence principle) that the speed of light in the absence of a gravitational field is c+v, where c is the speed of photons relative to the light source and v is the relative speed of the light source and the observer. This means that VARIABILITY OF THE SPEED OF LIGHT IN A GRAVITATIONAL FIELD IS FATAL FOR EINSTEIN'S THEORY AND MODERN PHYSICS IN GENERAL:

Albert Einstein:

"If the speed of light is the least bit affected by the speed of the light source, then my whole theory of relativity and theory of gravity is false."

"I consider it quite possible that physics cannot be based on the field concept,i.e., on continuous structures. In that case, nothing remains of my entire castle in the air, gravitation theory included, [and of] the rest of modern physics."

Pentcho Valev