In the Planck Gravity Theory, there is a new coupling between cosmic expansion and gravity. With this new gravitational coupling, we can simply explain the phenomenon of accelerated expansion of the universe. The properties of the new gravitational coupling are consistent with the characteristics of dark energy and experimental measurements. This proves that the new gravitational coupling is dark energy. Dark energy does not exist. This theoretical model is also a method of accurately measuring the total mass of the universe. By making precise measurements of the rate of expansion of the universe, the total mass of the universe can be calculated.