What would most likely cause the future acceleration of the expansion of the universe

The answer is dark energy. This is the energy in the universe that opposes the gravitational attraction of matter in the universe. Initially, cosmologists had thought that the universe was decelerating due to the gravitational attraction between matter in the universe after the big bang. However, using the Doppler shift effect, evidence was gathered on the nature of the expansion of the universe.

jupiter is the largest planet in our solar system, having a mass and radius that are respectively, 318 and 11.2 times that of earth. suppose that an object falls from rest near the surface of each planet and that the acceleration due to gravity remains constant during the fall. each object falls the same distance before striking the ground. determine the ratio of the time of fall on jupiter to that on earth.