What is the red line on the globe?

The red line on the globe is the ecliptic line, which actually represents the orbital plane of the earth's revolution. The different solar terms above refer to the point where the sun shines directly, which is the solar term.

The ecliptic is the great circle where the earth's orbit around the sun intersects the celestial sphere, corresponding to the equator. The earth revolves around the sun once a year. From the earth, we see the sun moving 365 or 366 times a year in the sky. The route of the sun's movement is called the ecliptic-it is an imaginary great circle on the celestial sphere, which is the projection of the earth's orbit on the celestial sphere. The ecliptic intersects the equatorial plane in vernal equinox and vernal equinox.

Revolution leads to the change of seasons, and rotation leads to the alternation of day and night.