From the geography of senior high school and the dichotomy between the earth and the sun

The straight line you draw is the earth axis.

The revolution direction of the earth is counterclockwise (from west to east).

Left and right earth: On the same earth, the summer solstice is close to the North Pole and the winter solstice is close to the South Pole.

As shown in the figure below:

Earth A in figure 1 and Earth C in figure 3 are close to the north pole of the sun, so it is the summer solstice; Earth C in figure 1 and Earth A in figure 3 are the South Pole, which is close to the sun, so it is the winter solstice.

Knowing the summer solstice and winter solstice, you can know the vernal equinox and autumn equinox by clicking it counterclockwise.