The electrons are not held in place (only) by gravity, they are held by other forces. If it was just gravity that held them then they would just leave the little tiny weak pull of gravity towards the nucleus(very small mass) and head towards the big powerful pull of gravity of the earth(very big mass).
Originally posted by Waldo2k2
>>, the nucleus has gravity over the electrons. Speed can increase (effect) weight, soooo, theoretically the electrons will become too heavy for the nucleus to retain it's gravitational pull over them....