According to National Geographic, equinoxes are when Earth’s subsolar point (where the sun’s rays shine perpendicular to the Earth’s surface) passes through its equator. During an equinox ...

Of course, the technical definition is that spring begins on the vernal equinox, which marks the point when the sun’s sub-solar point is directly over the equator. The vernal equinox occurred ...

A sub-solar point is when the sun is directly overhead at a particular latitude. When the sun is at the zenith (the highest point in the sky) its rays will be hitting a particular point exactly ...