As excitement builds over the coming autumnal equinox, which will occur for North Americans on the evening of September 22, it's a good time to learn about this and other kinds of celestial events. After all, looking up at the sky is something humans have done since forever. Here's what's actually going on, and some upcoming dates to keep in mind.
The spring, or vernal, equinox, will be March 20, 2019, at 5:58 p.m. Eastern time. The day (and time!) marks the beginning of spring. It is one of two days each year when the sun passes directly over the equator.