Re: Want to prove E=mc²? University labs should try this!

As I wrote before, the cavity NEVER reaches a steady state (thermal
equilibrium is just one possible goal to reach a steady state).
The stored energy increases constantly until the temperature of the
cavity
walls (not cancelled by any means) destroy the material that form the
cavity (either coatings or places on the cavity surface, making holes).
In physics, a steady state is a condition in which a system or process
does not change over time, or any changes are balanced out. This means
that the variables that define the system's behavior remain constant.
Some examples of steady states include:
Bathtub with a running tap: After a while, the water level stabilizes
and the system is in a steady state.
Thermal equilibrium: Two systems are in thermal equilibrium when they
are at the same temperature and there is no heat flow between them.
In 72 hours none of these conditions are reached: No steady state nor
thermal equilibrium. The inner temperature increase constantly, due to
the accumulation of energy within the cavity.
Regarding the orifice used to inject the laser beam, I always thought of
using a directional micro-glass window that reflects, internally, laser
hits.