Solar term lamp

(1) connects the center of the earth with the sun. It is known that the direct point is located in the Tropic of Capricorn, so it is the winter solstice.

(2) Make the sun's rays pass through the vertical line of point B, and use the shadow on the other side of the sun's rays to represent the night hemisphere.

(3) At this time, the direct point is located in the Tropic of Capricorn, so the spatial distribution law of the noon sun height is decreasing from the Tropic of Capricorn to the north and south sides.

(4) Day and night on the equator are always equally divided, that is, day and night are 12 hours each. According to the characteristics of terminator line, the intersection time between equator and dark line is 18 hours. (5) According to the nature, the closer to the direct point, the higher the height of the sun at noon, so the bigger the point B is. Point B is located at the equator, so the linear velocity is the largest and the AB angular velocity is equal.

So the answer is: (1) Solstice in winter?

(2)

(3) It decreases from 23 26 ′ s (or tropic of Capricorn) to the north and south sides.

(4) 18, 12

(5)B, B, equal