The twin paradox is fun to think about over a glass of warm milk. the idea is that one twin (jan, the active one) is an astronaut, while her sister (jen) observes the trip at home from the stocker astroscience center. [maybe jen "just likes to watch"] jan travels to alpha centauri (a distance of 4.22 light years), spends 1.00 year there taking measurements, and travels back to earth (again, a distance of 4.22 lightyears) and the spaceship has a velocity of v 0.9c (as measured in the frame of jen. obviously, the spaceship has no velocity as measured in the frame of jan). a) how far away does each sister see the distance between earth and alpha centauri? b) how long would jan measure for the time of the entire trip? c) how long would jen measure for the time of the entire trip? d) the texts like to talk about proper time. which frame here is the proper time? e) initially, since jan and jen are twins, they are the same age. which sister is now older? each sister thinks that in her frame, she sat still which is the paradox. f how do you fix that paradox?