As a high-speed spaceship flies past you, it fires a strobe light that sends out a pulse of light in all directions. An observer aboard the spaceship measures a spherical wave front that spreads away from the spaceship with the same speed c in all directions. (a) What is the shape of the wave front that you measure? (i) Spherical; (ii) ellipsoidal, with the longest axis of the ellipsoid along the direction of the spaceship’s motion; (iii) ellipsoidal, with the shortest axis of the ellipsoid along the direction of the spaceship’s motion; (iv) not enough information is given to decide. (b) As measured by you, does the wave front remain centered on the spaceship?

As a high-speed spaceship flies past you, it fires a strobe light that sends out a pulse of light in all directions. An observer aboard the spaceship measures a spherical wave front that spreads away from the spaceship with the same speed c in all directions. (a) What is the shape of the wave front that you measure? (i) Spherical; (ii) ellipsoidal, with the longest axis of the ellipsoid along the direction of the spaceship’s motion; (iii) ellipsoidal, with the shortest axis of the ellipsoid along the direction of the spaceship’s motion; (iv) not enough information is given to decide. (b) As measured by you, does the wave front remain centered on the spaceship?