🚀 go-pugleaf

In article <mcirvin.711904014@husc8>, mcirvin@husc8.harvard.edu (Mcirvin) writes...
> 
>Actually, neither definition of mass would be temperature-independent,
>if you define it for the whole lump of coal.  When you raise the
>temperature, the energy in the rest frame increases!  The sum of
>the masses of all the particles is perhaps temperature-independent,
>but as you complained before, that's not the mass of the lump.

But inertial mass *can* be termperature dependent.  Consider experiments
now being done to "weigh" molecules in Penning traps and other such devices.
They are getting (soon) to the precision where you can actually "weigh" the 
molecular bond between two atoms (i.e., detect the difference between the
mass of two protons + two electrons vs. a hydrogen molecule which is the
result of the binding energy).  If you had a sufficiently hot sample
of hydrogen, in which some molecules were in excited molecular orbitals,
and you weigh some of these molecules, you will find that the inertial
mass is different for molecules in different orbital configurations - 
the mass of a hydrogen atom depends on the temperature of the gas.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver