What little I know about equinoxes is that they mean that days are as long as nights. However, even that little tidbit of knowledge is erroneous, and I stand corrected after reading this article by Phil Plait on Scientific American. It's a slight misconception but if we were to be factually accurate, then it is important to get the equinox right.
In some ways, defining what the equinox isn’t is easier than describing what it is.
For example, it’s not when the day and night have equal lengths. That’s a common misconception and an understandable one. The trouble’s right in the name: “equinox” means “equal night”, implying that day and night are each 12 hours long. But it turns out they’re only mostly equal because of a couple of pernicious physical facts.
To know further what an equinox is, read the rest of Phil Plait's article here.
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