And I don’t mean the Chevy. Really there isn’t much significance to the equinox other than geographical interest. It is a consequence of Earth’s axial tilt – called precession. That link is a neat video if a bit inaccurate though since the Earth doesn’t wobble quite like that. Here is a more descriptive image – Right now the Earth is in the bottom most position working our way around to the right. It is the time from which the days get shorter as the north pole moves further away from the sun. It marks seasonal transitions which are otherwise arbitrary. From a climate standpoint the vernal and autumnal equinoxes are static markers from which one can measure an earlier or later spring/summer and lengths of growing seasons. Personally, I think that all Earth calendars should be synced to it, but I’ll get back into that in December.
I always think of the equinox as being the planet in profile. It is like a perfectly side on view. There’s something dignified about it.
Interestingly, Saturn just had its equinox as well – which only happens about every 15 years. Prime desktop background material there for the astrogeeks.
