Q: What is the vernal equinox?

The Spring Equinox is defined as the day on which the spring season begins astronomically, in which the Earth is in a moderate position relative to the Sun (not tilted) so that the sun’s rays perpendicular to the Earth’s equator, so the day of the vernal equinox is equal in length of night with day throughout the Earth .

The vernal equinox occurs in March of each year in the northern hemisphere, and in September in the southern hemisphere.. more