Latitude of direct sunlight when the Earth travels to vernal equinox.

(1) As can be seen from the schematic diagram of the earth's revolution, when the earth is in position A, the sun is facing the Tropic of Cancer, which is the summer solstice in the northern hemisphere, and the date is around June 22nd. When the earth is in position B, the latitude of direct sunlight is the Tropic of Cancer, that is, the winter solstice in the northern hemisphere, and the date is around June 22nd. (2) When the sun shines directly on the equator, it is the vernal equinox (about 2 1 year in March) or the autumn equinox (about September 23rd) in the northern hemisphere. When the earth is in position A, the sun shines directly on the Tropic of Cancer. (3) The direction of the earth's revolution is from west to east, so the answer is: (1) summer solstice; Solstice of winter; (2) March 2 1 or so; Tropic of Cancer; (3) .