We have non-speculative, concrete evidence that dark energy is the mechanism of gravity, analogous to the U(1) spin-1 electrodynamics field equation, so the lagrangian for repulsion of masses has a similar propagator for repulsion of similar charges in QED (Moller scattering). Therefore, in the presently-observable (low energy) limit of quantum gravity (very small coupling), Feynman’s well-tested rules for calculating the perturbative expansion of the path integral show that: (a) only the term for 2-vertex, tree-level interaction (Moller scattering) diagram in the perturbative expansion makes a significant contribution at low energy (the tiny gravity coupling suppresses the more complicated interactions in the expansion, since they have more vertices and hence pick up higher powers of the very small coupling), and (b) the cross-section (relative interaction probability, i.e. square of the sum of amplitudes), is proportional to the square of the coupling. So cross-sections from weak scattering of neutrinos can be multiplied by the square of the ratio of the known gravitational coupling to the known Fermi (weak interaction) constant (both expressed in units of GeV^-2), to find the effective cross-section for quantum gravity at low energy. This cross-section predicts the cosmological acceleration due to dark energy, a = (c^4)/(Gm), and automatically quantizes mass, revising the electroweak theory to include quantum gravity, with U(1) hypercharge now generating both dark energy and quantum gravity. This new paper uses a new diagram to improve understanding, and presents key facts in a single page to try to overcome inertia due to the lack of time most people have for "alternative ideas". More extensive and lengthy treatments can be found in other papers including: http://vixra.org/abs/1111.0111 and http://vixra.org/abs/1302.0004