In the Universal Acceleration model, all the celestial bodies including the earth are being accelerated in one uniform direction at roughly 9.81 m/s^2. The proposed method of propulsion is Dark Energy.
The elliptical orbits observed by Astrophysicists on earth are caused by planets moving along transparent, magnetic nexus rings. All significant celestial objects move along individual nexus rings. In addition, smaller objects such as asteroids may be slightly influenced by the pull of nexus rings. Nexus rings exert a small force on each other, but because of the vast amount of nexus rings in the universe, the net forces on each nexus ring are negligible.