During which event do the Sun's rays strike the equator directly?

During which event do the Sun's rays strike the equator directly?

• A. Spring and autumnal equinox
• B. Winter solstice
• C. Spring equinox
• D. Autumnal equinox

Answer: (A)

The Sun’s rays strike the equator directly when the subsolar point sits on the equator, which happens at the two equinoxes. On those days, the tilt of Earth’s axis places the Sun directly overhead at noon along the equator, so the rays hit the equator perpendicularly. That occurs during both the spring (vernal) and autumn (fall) equinoxes, so the full answer is spring and autumnal equinox. The winter solstice and summer solstice place the Sun over latitudes 23.5°N or 23.5°S, not the equator, and a single equinox would miss the other half of the year.

The Sun’s rays strike the equator directly when the subsolar point sits on the equator, which happens at the two equinoxes. On those days, the tilt of Earth’s axis places the Sun directly overhead at noon along the equator, so the rays hit the equator perpendicularly. That occurs during both the spring (vernal) and autumn (fall) equinoxes, so the full answer is spring and autumnal equinox. The winter solstice and summer solstice place the Sun over latitudes 23.5°N or 23.5°S, not the equator, and a single equinox would miss the other half of the year.