Experiment To Derive The Mass Of The Photon
Sven Gelbhaar
27 October 2008
We know that radiation exerts pressure on bodies of mass (wikipedia:
radiation pressure), that it acts as if it is subject to
gravity and therefore probably is (wikipedia: gravitational lensing), and
that its speed can be altered in laboratory conditions
just as if it has mass. But how can we find out how much mass a photon
has? How much does a photon actually weigh?
We set up a light-proof box, situated in a zero-gravity environment.
Inside we place an object that has a metric weight – say 1
gram. We then expose this object to a known amount of photons (we already
assume to know how fast they go by default so that
won’t have to be determined at this stage in the game), measure how far and
(more importantly) fast this radiation pressure
moves the 1 gram object, and then work backwards using the law of momentum
to solve for m(ass) (p=mv).
This assumes that quantum fluctations aren’t going to throw off our
results, so for a control we’ll leave the object suspended and ensure that
quantum phenomena aren’t moving the object. This should be superflous, as
we’ve already covered the Casimir Force here at /Occam’s Razor/ and it
should probably be discounted. Also we’ll have to
factor in gravitational force, and to do that we’ll use two different size
box enclosures.