Chapter 13, Problem 13.8OQ

The vernal equinox and the autumnal equinox are associated with two points 180° apart in the Earth’s orbit. That is, the Earth is on precisely opposite sides of the Sun when it passes through these two points. From the vernal equinox. 185.4 days elapse before the autumnal equinox. Only 179.8 days elapse from the autumnal equinox until the next vernal equinox. Why is the interval from the March (vernal) to the September (autumnal) equinox (which contains the summer solstice) longer than the interval from the September to the March equinox rather than being equal to that interval? Choose one of the following reasons, (a) They are really the same, but the Earth spins faster during the “summer” interval, so the days are shorter, (b) Over the “summer” interval, the Earth moves slower because it is farther from the Sun. (c) Over the March-to-September interval, the Earth moves slower because it is closer to the Sun. (d) The Earth has less kinetic energy when it is warmer, (e) The Earth has less orbital angular momentum when it is warmer.