The fundamental criticism against the book from the astronomy community was that its celestial mechanics were irreconcilable with Newtonian mechanics, requiring planetary orbits which could not be made to conform to the laws of conservation of energy and conservation of angular momentum (Bauer 1984:70). Velikovsky conceded that the behavior of the planets in his theories is not consistent with Newton's laws of motion and universal gravitation. He proposed that electromagnetic forces could be the cause of the movements of the planets, although such forces between astronomical bodies are known to be essentially zero.