🚀 go-pugleaf

In article <131163@lll-winken.LLNL.GOV> dk@imager (Dave Knapp) writes:



   In Article <1992Jul22.193837.18095@sfu.ca> palmer@sfu.ca 
   (Leigh Palmer) writes:

   > In order to illustrate my point, do you claim that a lump of
   > condensed matter has a the same mass as the sum of the masses of
   > its elementary constituents? Of course you don't.  That only
   > begins the parade of difficulties attendant to using the currently
   > fashionable definition outside its proper area of use.

   > To further confuse the beginning physics student you could explain
   > that the mass of that lump of matter is independent of its
   > temperature.

     This caricature of the "currently fashionable definition of mass"
   is pretty twisted.  Surely you can't be claiming that the use of
   "rest mass" as "mass" implies that one must use the sum of
   constituent masses to obtain the mass of an object?  If you are, then
   how do you think particle physicists define the proton mass?  As the
   sum of the masses of the constituent quarks?  Not likely.

     Hmmph.  I think I smell a straw man.  -- Dave

Nope. Define the mass of a neutron star, and consider that
most astrophycists will respond if asked: "baryonic mass
or gravitational mass?".
	Now for the tricky bit: given the distinction, explain
why a black hole's gravitational mass if non-zero and give an
operational definition...

*  Steinn Sigurdsson   			Lick Observatory      	*
* steinly@helios.ucsc.edu		"standard disclaimer"  	*
*  The laws of gravity are very,very strict			*
*  And you're just bending them for your own benefit - B.B. 1988*