What is the name of the imaginary line that divides the celestial globe into two hemispheres?

The imaginary line that divides the earth into in this case the north and south hemispheres is called the Equator and it passes through Ecuador and actually Ecuador is the Spanish word for Equator. The French explorer La Condamine spent 10 years in Ecuador studying the equator and determined the oblate spheroid shape of the world.

Answer they are produced by collision of tectonic plates;

If you dont know the answer dont commnent anything