§253c。 onsequences of Einstein' s postulates Example: your starship passes Earth with a relative speed of 0.9990c. After traveling 10.0 y(your time), you stop at lookout LP13, turn and then travel back to earth with the same relative speed. The trip back takes another 10.0 y(your time). How long does the round trip take according to measurements made on Earth? (neglect any effect due to the accelerations) Solution: Event l: start from earth Event 2: stop at LP13 Proper time: To=4,=10.0 y 8 25.3 consequences of Einsteins postulates The earth measurement of the time interval is 10.0 =224(y) √1-(v/c)2√1-0.99 On the return trip, we have the same situation and the same data. thus the round trip requires 2 total =448(y) 1-(v/c)15 Example: your starship passes Earth with a relative speed of 0.9990c. After traveling 10.0 y(your time), you stop at lookout LP13, turn, and then travel back to earth with the same relative speed. The trip back takes another 10.0 y(your time). How long does the round trip take according to measurements made on Earth?(neglect any effect due to the accelerations) Solution: Event 1: start from Earth Event 2: stop at LP13 Proper time: 10.0 y τ 0 = ∆t0 = §25.3 consequences of Einstein’s postulates The Earth measurement of the time interval is 224 (y) 1 0.999 10.0 1 ( ) 2 2 0 = − = − = = v c t τ τ ∆ On the return trip, we have the same situation and the same data.thus the round trip requires 448 (y) 1 ( ) 2 2 0 total = − = v c t τ ∆ §25.3 consequences of Einstein’s postulates