Okay, fair enough, there's more to mass than the simplicity of the equation might seem to indicate...

Thanks for the insights. :) Always good to get more info.

I guess I was just thinking of mass in terms, to some degree, of pressure, and deformation (a growing or shrinking sphere). I was also reading a physics book today (after my last post before yours), and about the relationship between mass and energy. And I think it kind of fit with my thought line (granted there may be more to it than the simplistic case).

Anyway, what I was reading sounded like the relationship between mass and energy was pretty direct, and to some degree matched up with the beach ball analogy earlier, IE, tightly packed systems may hold more "mass"/"energy" per volume than a less densely packed object. IE, the force of the energies used to pack the object tighter contributes to the overall energy of the system, thus its mass.

So, in some regards, my thought line goes along the lines of (on a basic level) mass is like "pressure." Say, when you take the beach ball and compress it down into a smaller space. You have the same amount of mass/energy but in a smaller space. But you have to also factor in the energy used to pack everything into the smaller space too (in the example of the physics book, they likened mass to a watch that's wound up; you have to account for both the mass of the spring that's wound, and the kinetic energy used to wind it that's stored as potential energy, thus increasing its mass). So, I guess I think of "mass" as "packed energy" or energy that's been pressurized within a sphere or other semi-stable structure.

And, I guess I see energetic reactions (in simple cases), kind of like the beach ball example. If you throw a rock at the beach ball, the beach ball deforms slightly, and is also imparted with more kinetic energy. But the resistance to the motion of the outside body increases, probably in a steep curve, the closer the interloping rock gets to the beach ball's center of mass. At some point the rock stops, when it no longer has enough energy to impart to the system. At that point, the outward push of the deformed (slightly more "mass"ive, or more energetic) beach ball becomes far greater than the energy exerted by the rock. Acceleration of the rock slows, stops, and the potential energy of the beach ball is converted into kinetic energy, ejecting the rock.

I guess it's that metaphorical resistance of the beachball to being moved, and growing resistance to the rock's motion based upon how deeply the rock travels that I'm seeing as the intensity of resistance that varies with distance from the center of mass. Obviously the beach ball might move a little bit, but probably not much, if the rock is small and not thrown very hard.

Don't know if that gels or not. But like you said, thre's all sorts of other ways of generating or dissipating energy aside from a straight pressure relationship. Appreciated.

I just thought the beach ball analogy was kind of decent for the mass energy realtionship as it relates to distance between objects, mass variation with "packing of energy" and "resistance to being moved" and/or collision interactions... Be it maybe not quite a perfect model...

All sorts of fun to consider new things. I'll do some more reading tho'. :)