The position of the Earth when the Northern Hemisphere has the longest day.
Explanation
The Summer Solstice is an astronomical event caused by the tilt of the Earth's axis as it revolves around the Sun. It represents the moment when the Sun reaches its highest position in the sky as seen from the North or South Pole, resulting in the maximum duration of daylight for that hemisphere.Option Analysis:
- The time when the Sun is vertically overhead at the Equator. is Incorrect: The position where the Sun is vertically overhead at the Equator corresponds to the Equinoxes (Vernal and Autumnal), occurring approximately on March 21 and September 23.
- The position of the Earth when the Northern Hemisphere has the longest day. is Correct: The Summer Solstice (typically June 21) occurs when the Sun is vertically overhead at the Tropic of Cancer (23.5° N). During this position, the North Pole is tilted towards the Sun, causing the Northern Hemisphere to experience the longest day and the shortest night of the year.
- The time when the Southern Hemisphere has the longest day. is Incorrect: This statement describes the condition during the Winter Solstice (typically December 22). On this date, the Sun is overhead at the Tropic of Capricorn, giving the Southern Hemisphere its longest day (Summer in the Southern Hemisphere) and the Northern Hemisphere its shortest day.
- The position when day and night are equal everywhere. is Incorrect: The position where day and night are equal everywhere on Earth occurs during the Equinoxes, not the Solstices.
Key Takeaway: The Summer Solstice (June 21) is characterized by the Sun being overhead at the Tropic of Cancer, resulting in the longest daylight hours in the Northern Hemisphere.