11, An astronomer on earth observes two spacecraft moving away from each other along an axis that passes through the earth, The Astronomer measures the speed of each spacecraft to be 0.65c relative to the earth. At what speed are the spacecrafts moving apart relative to each other? 0.91c 0.79c T- 1.30c V 0.46: 0.70c - D:65 - 065 4 - V 1 - dev 1- (cass X0.65