Final answer:
The sun's noon time rays are directly overhead on December 22 at the Tropic of Capricorn, marking the winter solstice in the Northern Hemisphere and summer in the Southern Hemisphere.
Step-by-step explanation:
The sun's noon time rays are directly overhead on December 22 at the Tropic of Capricorn. This is due to the tilt of the Earth's axis, which creates the seasons that we experience. The Tropic of Capricorn is the latitude where the Sun is at zenith during the December solstice. This phenomenon marks the beginning of winter in the Northern Hemisphere and summer in the Southern Hemisphere. Therefore, for locations on the Tropic of Capricorn, the Sun will be at an altitude of 90° at noon - directly overhead.
During the winter solstice, which occurs on December 21 or 22, the Sun's rays shine directly onto the Tropic of Capricorn at noon due to Earth's axial tilt of approximately 23.5°. This is also why the North Pole experiences 24 hours of darkness during this time, and conversely, the South Pole enjoys continuous daylight.