US Has Heavily Researched Anti-Gravity, Book Says

150- good question - "We are in fact slidding down a slope created by the gravity of the center of the earth. The old 'curved-spave' analogy is useful. But what force is making us "slide down" these four-dimensional curves? "

are you trying to tell me that one photon of light will cancel out another photon of light?

No.

"Physicist" was trying to explain to you that "regular" particles have "mirror image" (in a manner of speaking) counterparts, called sometimes called "anti-particles." The counterpart to the electron is called a positron. It has exactly the same properties of and electron, except its electric charge is the positive instead of negative; thus the charge "cancels" that of an electron.

In the case of some particles that have no electric charge, the mirror-image particle turns out to be the particle itself. This is the case for photons, and, as "Physicist" has been patiently trying to explain, under any prosed formulation of quantum gravity, for a gravity particle. In such cases where the particle is its own conjugate (self-conjugate), they do not cancel each other out. That's the whole point.

"Physicist" is trying to explain that there is NO theoretical basis on which to hypothesize an "Anti-gravity particle" (which would posess the property of "cancelling" gravity), as this role is reserved for a particle's anti-particle, but when that role is played by the particle itself (when a particle is self-conjugate), there can be no cancellation effect, because in that case the anti-particle possesses the SAME, not the opposite, characteristic needed to cancel that of the regular particle.

I regret having attempted to explain Physicist's point; I seem to have caused more confusion than clarity.

keep trying, and thanks for trying. It is sometimes hard to get down to an understandible level, as one is used to using the jargon of the technical specialty with which you are familiar. Thanks to both of you, I am beginning to understand.

Yeah, the "Al Martin Raw" site is good on that connection.