Astronomy Practice Exam 2025 – Complete Preparation Guide

A solstice is defined by the position of the Sun relative to the Earth at specific times throughout the year, particularly during the summer and winter seasons. This phenomenon occurs twice a year when the Sun reaches its highest or lowest point in the sky at noon, resulting in the longest day of the year during the summer solstice and the shortest day of the year during the winter solstice.

During the summer solstice, typically occurring around June 21 in the Northern Hemisphere, the Sun is at its highest point, resulting in the longest duration of sunlight. Conversely, during the winter solstice, around December 21, the Sun is at its lowest point, leading to the shortest duration of daylight. This behavior is due to the tilt of the Earth's axis relative to its orbital plane around the Sun.

Therefore, the defining characteristic of a solstice is indeed the positions of the Sun at its highest and lowest points in the sky, marking these pivotal transitions in the seasonal cycle.