In your opinion what causes christians to believe in Jesus

[Thumpalumpacus]

Relativity is actually an add-on to Newtonian physics.

Gravity barely even exists under Einstein, and certainly not in the way Newton thought of it. For Einstein what exists is spacetime, and what we call gravity is nothing more than a curvature in it's fabric.

Gravity exists for everyone, and both Einstein and Newton endeavor to explain it. That relativity addresses much different forces as well, and in much smaller scales, doesn't take away from how it aided further understanding of gravity.