hi, i have recently been studdying reletivity and the whole e=mc^2, mass energy exchange stuff... and i have a major question (in my mind) that i can't get answered, sincei don't have a teacher, i thought this would be the best palce to come... What happens when you start accelerating an electron and dump in in a sun's gravitational field. it gains gravitational potential energy, so what happens now? does alll that gravitational potential energy add to the energy you put into the electron to accelerate it to this speed? how does the mass of the electron change? does it get bigger the instant it enters the field and gravity starts acting on it? or does it gain mass as it starts to fall and pick up kinetic energy? please clear this up for me, it's really bothering me, i am able to see that the mass of an electrong doesn't instantly increase when you put it on a spring, but that's spring potential. (i think i just answered my own question). but please give me feed back.