Question

What are hemispheres?

Answer 1

Hemispheres are the halves of a sphere into which the sphere is divided by a plane through its center.

Explanation:

For the Earth, the equatorial plane divides Earth into two hemispheres, with surface 0 deg to 90 deg latitudes, in the North and South of the equator, respectively.
The latitude at the equator is 0.
The zenith of the northern hemisphere is North Pole (lat 90 deg N). The South pole is antipodal, at 90 deg S. .