I’ve returned from the Christmas (and, here in the Southern Hemisphere, summer) holidays and, after settling back in to my office, I began the daunting task of dealing with the torrent of emails that came in over the 3 or so weeks I was away (hence a need to let off some nervous energy in a blog post… 😉
You know what I mean – a veritable maelstrom of email arrives during a break from work when you’re not looking. Hmm, a maelstrom of email: an “e-maelstrom”, if you will. 🙂
I’m not sure this qualifies for the Washington Post’s new words competition – take a word, change one letter and give it a new defintion – but it surely has resonance for many of us at this time of year (and especially here in the Southern Hemisphere where our holidays tend be longer owing to summer). And I’m sure the concept applies equally well to any return to work following time away from email.
Anyway, a new year has begun – but not, I would argue, on the 1st of January, which is an entirely arbitrary day in the Earth’s orbit around the Sun. Better candidates for clicking the numbers over might be one of the solstices or equinoxes, but my personal favourite is perihelion – the point in its orbit at which the Earth is closest to the Sun. The orbit is not circular but slightly elliptical, so there is a closest point – perihelion – and a furthest point – aphelion, since not all points are equidistant owing to the non-circularity. And therefore, although you might not have thought about it, the seasons don’t have the same length. Indeed, we lose a few days of summer here in the Southern Hemisphere as a result, while also getting a higher flux of solar energy than that experienced during summer in the North.
Owing to the variations of the Earth’s position and movements – the well-known Milankovitch Cycles – the seasons (which are governed by the cyclically-variable axial obliquity or tilt of the Earth’s axis, as well as its axial precession) do not necessarily line up or have any connection with the independent variations in the shape and position of the orbit (including changes in its eccentricity or “ovalness”, as well as its own apsidal precession). However, in this epoch, perihelion occurs close to the December solstice (northern winter, southern summer) around Dec 22 and even closer to conventional New Year’s Day. Currently, perihelion is around January 3 or 4, depending on your time zone and whether we are in a Leap Year (which we are), so I think we should use the Earth’s physcially-meaningful perhelion as the natural starting point to mark the start of an orbit, and thus also of a year. It makes much more sense to do this, in the same way that 0 C makes much more (physical) sense than 32 F to mark the freezing temperature of water (at 1 atm pressure).
So Merry Perihelion everyone and a Happy New (apsidally-defined) Year! And I hope dealing with your own e-maelstrom won’t be so bad now that you can “name the Dragon” 😉
Now, back to it…