Science Questions

Ali & Steve asked the Naked Scientists: Could there be an antimatter equivalent to light it makes sense that the positron would set up an electric field/magnetic field as it moved from one level of excitement to another just as an electron does but the radiation would have it's poles reversed? It should also annihilate normal light? Steve Thompson Lankeys Creek Australia What do you think?

yes the antimatter equivalent of light is light a photon is its own antiparticle  (this is not the only case of this in quantum mecanics)it is quite possible for one photon to cancel out another. you see this effectively where you get destructive interference.

However thats not quite the full story because photons are always on the move and unless these photons are carefully aligned so that they always cancel this anhilation will only happen briefly at one instant of time

Dark energy, if it exists, would be the antimatter equivalent to light.  Photons are regarded as their own anti-particles but this only applies to their phase, and two anti-phase photons will not annihilate each other (the product of which would be photons), but will only cancel each other at the point of collision.  The photons will carry on afterwards, as before the collision, with no loss of energy.

Light is not matter, and trying to relate anti-matter properties to something that is not matter doesn't work.

Can you explain your reasoning behind that? The only thing I can think of is that "dark" is the opposite of "light"; but that is just terminology. I'm sure an intellect such as you possess would not make such a spurious connection except in jest.

<<it makes sense that the positron  would set up an electric field/magnetic field as it moved from one level of excitement to another  just as an electron does but the radiation would have it's poles reversed?
It should also annihilate normal light?>>

a positive charge's motion generates the same electromagnetic radiation generated by a negative charge's motion.

DrB - that's not an assertion of any authority.  Heh - any assertion that invokes Dark Energy is speculation but some scientists believe that DE may effectively be negative energy.

Can't quite get my head around it, personally.

My intellect is old and knackered, and I'd rather you didn't draw attention to it.

I would take issue with your idea of photons 'annihilating' each other.
Waves may add constructively or destructively but the photons, if you insist on including them in this particular part of the process, are merely re-directed away from some parts of the diffraction pattern (troughs) and directed to others (peaks).

Uncertainty cannot allow you to specify the phase, frequency and position of two photons and predict how they will 'affect each other'.

Why oh why do people have to keep the 'little bullet' picture of photons in their minds. It is such a fraught concept. Stick to waves because they will tell you what will happen on the journey. Photons will help to describe the interaction. The small thing about a photon is its energy - its 'size' is not relevant (or even meaningful, I believe) to understanding and predicting what goes on.