Showing posts from August, 2015

Dog Days

Last month, if you happened to glance at the southeastern horizon at dawn, before the sky was bleached by daylight, you'd have seen a bright star rising. In Greek mythology, Sirius, the brightest star in the northern night sky, was the Dog Star, the canine companion of Orion the trophy hunter (he once bragged he'd kill every animal on Earth). The fact that the star rose together with the sun at the hottest time of the year led ancient Greeks to suppose that Sirius was responsible for that heat. Hence, the dog days of summer - a classic instance of confusing correlation with causation. Reality is, as always, stranger and more interesting than superstition. In the nineteenth century, Sirius was found to be in fact a double star. The previously unseen companion is a white dwarf , a fantastically dense object held up against the crush of gravity by an exotic quantum mechanical effect. Thoughts of ancient superstitions and modern physics flitted through my head as I sweated up