Part 1: Using scientific laws, given the current positions, velocities and sizes of the planets, we can predict their future positions. Is it fair to say that the current situation explains the future situation?
Part 2: Does the scientific law cause the future situation?
Part 3: Because the laws are reversible with respect to time, future configurations can be used to compute current ones. Is it fair to say that the future situation explains the current situation?
Part 4: Does the future situation cause the current situation?