A(n) ______ marks the beginning of summer and winter.

• A. Perihelion
• B. Solstice
• C. Equinox
• D. Ceres

Answer: (B)

The time when seasons begin in a noticeable, astronomical sense is tied to the tilt of Earth and how the Sun appears in the sky. A solstice is when the Sun reaches its most extreme position northward or southward relative to the celestial equator, producing the longest day in summer and the shortest day in winter. In the Northern Hemisphere, the summer solstice occurs around June 21, marking the start of astronomical summer, while the winter solstice occurs around December 21, marking the start of astronomical winter. The sun’s extreme position at these times is what drives the change in daylight length that defines those seasons. This differs from an equinox, when day and night are equal and it marks the beginnings of spring and autumn. Perihelion is simply Earth being closest to the Sun, and Ceres is a dwarf planet, not a season marker.