# Relativistic Mass and Gravity

*Most recent answer: 11/06/2014*

- John C Murray (age 63)

Vancouver BC Canada

The inertial mass does blow up toward infinity as the speed v approaches c, but not following an exponential form. It goes as (1-(v^{2}/c^{2})^{-1/2}. The argument as to why it follows this form would apply to anything with rest mass, regardless of what causes the rest mass. Poincare' and Einstein had figured it out long before anyone dreamed of Higgs particles.

Yes, this increase in inertial mass does show up in the gravitational attraction. That's easiest to think about for a bag of particles whizzing about in all different directions, so the net momentum is zero, just like for a particle at rest. The gravitational effect comes from the sum of those inertial masses, bigger than the sum of the rest masses.

Mike W.

*(published on 11/06/2014)*