Show that in general a skew-symmetric tensor such as the spin tensor W has only one real principal value λ. Determine λ and the corresponding direction ˆn in terms of the components w1 = −W23, w2 = −W31, w3 = −W12 of the vector ˆω.

According to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does maria's voyage take according to samir?