Today is the first day of summer in the Northern Hemisphere, or as Neil deGrasse Tyson would call it, the summer solstice. You might think, “If today is the solstice…then what the heck is an equinox?” Here’s a cheat sheet:
- A solstice occurs when one of the Earth’s poles (today, it’s the north) tilts toward the sun at the maximum angle. The two solstices, in December and June, mark the beginning of winter and summer and give us the longest days and nights of the year.
- Equinoxes are essentially the opposite of solstices. Deriving from the Latin for “equal night,” the equinox is when the sun is directly over the equator, leading to roughly the same amount of day and night. Spring and fall begin on equinoxes.