Tropic of Capricorn, latitude approximately 23°27′ S of the terrestrial Equator. This latitude corresponds to the southernmost declination of the Sun’s ecliptic to the celestial equator. At the winter solstice in the Northern Hemisphere, around December 21, the Sun is directly over the Tropic of Capricorn and lies within the boundaries of the constellation Sagittarius, having reached its southernmost declination in the ecliptic. Previously, however, it appeared in the constellation Capricornus at the winter solstice—hence the name Tropic of Capricorn. Because of the gradual change in the direction of Earth’s axis of rotation, the Sun will reappear in the constellation Capricornus in approximately 24,000 years. (See Tropic of Cancer.)