polar symmetry at the Equinox

UMass Sunwheel

Clouds partially obscured sunset at the UMass Sunwheel this evening, but the day was glorious and could not be damped by moisture at high altitudes. vernal equinox 2010 at the sunwheel Dr Judith Young’s astronomy lesson drew a crowd of over a hundred on this warm spring day.

I always learn something new from her “every day astronomy” as she labels the astronomical events that occur every day, 365 days a year, always and forever as long as the earth turns.  Today I was struck by the symmetry of light at the North and South Poles. If I got it right, today is the only day – just once in the entire year – when both the North Pole and the South Pole receive light from the sun. Not only do they each receive sun at the same time (once in 365 days) but they receive it for the whole day: an entire 24 hours.

Imagery came to mind as she spoke, of the earth rotating in a slow swirl of light and dark, pulsing back and forth (pendulum-like?) from this day of total light at the top and bottom to the opposition in six months, when both poles will be simultaneously in total dark for another single day. The North will swirl on, now, in permanent light, while the South twirls in darkness.  The pattern will shift a bit from day-to-day until the Fall Equinox reverses the trend, casting the North toward the dark and the South back into the light.  (There must be a good animation of this?)

Imaginational error!  Ha – I did find an animation, and it doesn’t look at all like I had visualized! The movement is an uneven rocking, not the smoothly symmetrical dance of intertwined light-and-shadow flitting about my brain. Well. Imagination is just that, right? Imaginary.

I also located Dr Young’s astronomy podcast for today, which proposes an International Unity Day in addition to including most of the information she shared on site. The proposal is premised upon the fact that for this one day only, everybody on earth is positioned relative to the sun in exactly the same way.

Coordinates (for coordinating)


During her talk at the Sunwheel, Dr Young made an off-hand comment about how Eskimos experience the sun very differently than we do. It gave me an idea about the Sapir-Whorf hypothesis, which poses the idea that people’s experience of the world is different because of the influence of their particular language.  It isn’t that the language per se generates a different world, but that the language reflects the particular coordinates of how a culture experiences the world around them. Then I remembered Bakhtin’s heteroglossia, which theorizes that every one (each individual) has, to some extent, their own language.

Given such a vast sum of possible variations (be it with languages or experiencing the sun) it is quite amazing that there are days (infrequent, and thus perhaps special) when anyone paying attention would discover that they were oriented to the sun in exactly the same way as everyone else (with exceptions at the extreme latitudes). It is as if the earth moves in such a way as to produce a single coordinate system – just a taste, for a time, to prove it is possible?

Dr Young (in her podcast, linked above) lists the 4 characteristics of the Equinox –

  1. the Sun rising due East,
  2. the Sun setting due West,
  3. the Sun up for 12 hours, and
  4. the Sun down for 12 hours.

And the amazing thing is that everyone on Earth sees this on the Equinox… So you may be located in Australia, or Ireland, or Ecuador, or Amherst, Massachusetts (where I am) and whether you are in the Southern hemisphere or the Northern hemisphere or at the equator, on the Equinox you will see the Sun rise due East and set due West, with 12 hours of Sun up and 12 hours of Sun down.

Just think about it – on the day of the Equinox, all creatures inhabiting the Earth will experience the same thing with regard to the direction of sunrise and sunset, and with regard to the length of time the Sun is up and the length of time the Sun is down.

Most days it is pretty hard to imagine umbrellas large enough to encompass all differences.  Personally, I’m eager to help create them.  I’ve joined this organization Four Years. Go. Perhaps it will keep me out of trouble (one hopes) when I’ve nothing else to do!

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