Equinoxes and solstices are a result of two things: Earth’s tilt and its orbit around the Sun. Solstice, the term comes from the Latin words sol and sistere , meaning “Sun” and “to stand still” . Initially, the naming arose from observations of how the Sun’s apparent path across the sky changes slightly from one day to the next, which is caused by the same process as the subsolar point's movement described above. In the months leading up to the December solstice, the position of sunrise and sunset creeps southward. On the day of the solstice, it reaches its southernmost point. After that, the daily path of the Sun across the sky begins to creep northward again. The winter solstice , also called the hibernal solstice , occurs when either of Earth 's poles reaches its maximum tilt away from the Sun . This happens twice yearly, once in each hemisphere ( Northern and Southern )....