When Xiao Ming opens the calendar and sees the solar terms below, where does the earth run in the picture on the right? Point a a b b c c

Test analysis: Point A is the tropic of Capricorn, which is the winter solstice in the northern hemisphere, and the date is about 65438+February 22nd. Point BD is the equator, which is the vernal equinox and autumnal equinox in the northern hemisphere, and the dates are around March 2 1 and September 23. Point C is the Tropic of Capricorn, which is the summer solstice in the northern hemisphere, and the date is around June 22nd.

Comments: This question can also examine the length and change of day and night caused by revolution: it is formed by the revolution of the earth. The distribution of the length of day and night from two points to the whole world: ① Summer solstice (summer), the polar day of the Arctic Circle and the polar night of the Antarctic Circle, the farther north the day is, the shorter the day is. The northern hemisphere has long days and short nights, but the southern hemisphere is just the opposite. The solstice in winter is just the opposite of the solstice in summer. ③ On the vernal equinox in Changchun, the terminator line coincides with the earth axis, and the global day and night are equal in length. ④ The length of day and night at equatorial latitude is equal throughout the year. So there are: the winter solstice is long, the summer solstice is short, the vernal equinox and the autumnal equinox are equally divided day and night, the summer solstice in the northern hemisphere is long and the night is short, and the winter solstice (winter) is short and the night is long; The southern hemisphere is the opposite; The change and shadow of the height of the sun at noon: formed by the revolution of the earth. The direct point of the sun has the highest height (the angle is 90 0), and there is no shadow; The farther away from the direct point, the lower the height of the sun and the longer the shadow. The higher the latitude is, the longer the shadow is in areas with latitudes greater than 23.5° 0° N and 23.5 0 S.: Rotation produces alternation of day and night and time difference. Because of the earth's rotation, the hemispheres alternate between day and night, and the time is early and late: because of the earth's rotation, the East always sees the sun before the West; Therefore, the time in the east is always earlier than that in the west, thus forming the time difference on different meridians (positions), that is, instantaneous difference.