The Modern Physics Puzzler

Earth and Dearth are separated by exactly 10 lyr and are essentially stationary relative each other. Jack and John are born simultaneously (t = 0) on each planet, respectively. Note their births are simultaneous in their inertial reference frame.

Jill is born on a spaceship at the instant it is just passing Earth when Jack is born. The observers on the spaceship and earth all agree that Jack and Jill were born when the spaceship passed by Earth, that Jack's clock read t = 0, and Jill's clock read t' = 0. The spaceship is traveling at .98c towards Dearth. (Take gamma ~ 5) Use the relativistic transformation equations to answer the following:

  1. What age will John "appear" to be and what age will Jill appear to be when the spaceship passes by Dearth?
  2. According to Jill, at what metabolic rate has John been aging?
  3. Is there a contradiction in your answers to the first two questions? Explain. (Hint: Calculate when John was born, according to Jill. That is, what are the x' and t' coordinates for John's birth.)

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