Extra Attraction Generated by Spacetime Fluctuations

We show that, due to the nonlinear nature of gravity, fluctuations in spacetime curvature generate additional gravitational attraction. This fluctuation-induced extra attraction was overlooked in the conventional understanding of the cosmological constant problem. If the quantum vacuum of matter fields possesses positive energy and negative pressure, it would produce enormous gravitational repulsion, resulting in a catastrophic explosion of the universe -- the acceleration of the universe's expansion would exceed the observed value by some 120 orders of magnitude. We argue that such an enormous repulsion produced by the violent matter fields vacuum can be completely suppressed by the even more substantial attraction generated by the zero-point fluctuations in the spacetime curvature. As a result, the predicted catastrophic explosion of the universe is averted. Furthermore, at small microscopic scales, the structure of spacetime becomes locally highly inhomogeneous and anisotropic. When averaged over large macroscopic scales, the zero-point fluctuations of spacetime itself could drive the observed slow acceleration of the universe's expansion through a subtle parametric resonance effect.