We’re well into the Dog Days – an interesting time of year for a number of reasons, from traditional harvest festivals to hot nights and their well-documented ill effects on our tempers. I’m therefore honoring the effects on our minds, bodies and spirits, with a short discussion of how the term Dog Days has come down to us over many centuries. From where did such an odd expression arise?
Dog Days extend roughly from late July to mid-September in the Northern Hemisphere, those muggy days when rain is welcome for its cooling effect, then cursed in its passing for the rise in humidity. The generally miserable character of this period has been recognized for millennia, as we need only step outdoors to imagine.
The brightest star in the sky – apart from the Sun – is Sirius, the primary star of the constellation Canis Major, or Great Dog. It is so bright, and its spectrum so intense, that the ancients thought it provided the Earth with heat. Sirius is the bright star that seems constantly to be changing colors, hanging about 10-20 degrees above the southern horizon for much of the year, depending on the observer’s latitude. However, during this part of the year Sirius is in conjunction with the Sun, meaning that they are more-or-less in alignment, and rising and setting at about the same times.
Our ancestors believed that this conjunction of the Dog Star and the Sun was the reason for the heat of late Summer – the star’s effects being added to that of the sun and thereby causing the exceptionally hot weather. We, of course, know that Sirius is about 8.6 light years from us, (or roughly 5 trillion times as far away as the Sun,) and that it is having no measurable effect on the temperature, even allowing for the greenhouse effect. Nonetheless, we once more honor the beliefs of our forefathers with our references to the Dog Days of Summer.