[Suicide Junkie]

quote:
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What is the exact value of the mass of a given photon?
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The exact value is unknown. I can not give you an exact value.

I can!
The energy of a photon is E= hf (planck constant times frequency)

E= MC^2, so M = E/C^2 so M = hf/C^2

For a 650nm photon from your red laser pointer there, it weighs: = 6.6e-34 x (C/6.5e-7) / C^2
= 3.4 x 10^-33 grams
Which equals zero to an accuracy of 1 part in a quadrillion quadrillions. Or a European "Million Trillion"

The silicon chip or magnetic tape has the same mass and number of electrons regardless. It's just that the little bits are in different positions depending on if they are ones or zeros.

Position is important, though. Take Uranium 235, for example. Now take roughly half the nucleons aside .
You have the same particles sitting around, but less mass and more energy than you know what to do with.

[ August 18, 2003, 16:03: Message edited by: Suicide Junkie ]