On Tue, Mar 15, 2016 at 10:32 PM, Vibrator ! <[email protected]> wrote: > That's conflating relativistic mass with rest mass. I know the conclusion > that potential energy raises a system's mass is commonly accepted as an > inevitable implication of GR, but it's one frought with pitfalls: > > For instance, i dig a 1 meter-deep hole next to a 1 kg mass, at 1 G the > system now has 9.81 J of PE. But is there a relativistic mass increase (i > don't care how small it'd be - multiply the scale if you wish)? > > What if the mass never falls into the hole? > > Similarly, a vertical wheel is balanced on a hilltop, with an unequal drop > on either side, so the system's PE is indeterminate - could relativistic > mass also be indeterminate? >
The gravitational potential energy has a maximum finite value at an infinite distance from the earth. The point at infinity ensures that gravitational potential energy does not have to be arbitrary. As one moves closer to Earth the potential energy decreases relative to this maxium value. Harry
