Chapter 13, Problem 50A

To determine

To identify: Whether an expansion of universe is consistent or contrary with law of gravitational law

Explanation of Solution

Introduction:

The distance between two gravitationally unbounded parts of the universe increases with time is known as expansion of universe. This is intrinsic expansion of universe. Due to this expansion scale space itself changes.

Concept:

Present evidence indicates that expansion of universe is slowing down which is consistent with the law of gravity. As the galaxies are move away from the center of universe, also it is moving away from each other hence net force acting on it is decreases because of it acceleration of galaxies also decreases therefore, expansion of universe slowing down. Thus, the expansion of universe slow down (or deceleration of expansion of universe), which is consistent with the law of gravity.

Conclusion:

Hence, expansion of universe is accelerating is contrary with the law of gravitation.