Heide boards a spaceship and travels away from Earth at a constant velocity 0.45c toward Betelgeuse (a red giant star in the constellation Orion). One year later on Earth clocks, Heide’s twin, Hans, boards a second spaceship and follows her at a constant velocity of 0.95c in the same direction. 

(a) When Hans catches up to Heide, what will be the difference in their ages? 

(b) Which twin will be older?