Infinite mass = infinite gravity !? Someone asks me this: There is an object (in free space) attracted by a blackhole and accelerates towards it. Can the object be accelerated to light-speed-1？ I instinctively replied that "By Special Relativity, the mass will approach infinity as it moves closer to light speed, therefore it won't work." However, that person argues that as the mass approaches infinity, the G. force on the obj. also approaches infinity! How can this be answered? P.S. Additional thoughts: the mass and gravity actually never reaches infinity, right？ So...maybe the rate of increase of the former is much higher than the latter?