Nitesh was wondering:
> What the speed of Darkness would be?
The answer is:
Speed of Darkness = Speed of Light
Particle physics, helps us to really understand this. We shall assume the existence of an elementary particle called Darkon, to represent darkness. A Darkon as such has no mass & doesn’t travel, hence doesn’t exhibit no electromagnetic symptoms. Its nothing but an antiparticle of a Photon.
Darkness is driven by Light. Which means, a Photon hits a Darkon with the speed of light & drives it out. By applying, The Law of Collisions, we know that the speeds of the particles will be exchanged, as there is Conservation of Momentums. Therefore, a Darkon gains the speed of light & hurries out of the place. Hence the answer.
You might wonder what happens to the Photon, which became stationary? This explains why the intensity of Reflected Light is not always as that of the source.
Any Questions? >:O)
Update #0: After seeing the pic above, a thought just sparked. There is always a Darkon for every Photon & not viceversa. State the reason (take it as an Exercise!).