It was Gattis’ British television series Sherlock with Cumberbatch and Freeman that reawakened the tongues of English speakers to the lovely swinging ringlets of the phrase, “the obliquity of the ecliptic.” Once you know, you know. It’s the phrase we use to describe the 23 degree tilt of our earth on its axis with respect to the sun. I noticed its effect today in Amsterdam.

I learned about the obliquity of the ecliptic, and about the vernal and autumnal equinoxes, when I was around twelve years old, first from my Dad and then in an astronomy class I took at the University of Texas at San Antonio, then a small, new, commuter college where my father was the Director of the Division of Earth and Physical Sciences.

I was just a kid in middle school, but Dad spoke with the professors and they allowed me to audit an astronomy class and a geology class during my summer vacation. I wasn’t taking exams or being graded like the regular students of these summer courses, who were ten years older than me, but Dad made me report the exams and class work back to him and we worked on them together, sometimes.

I’d go to campus with Dad in the morning and spend the day there, taking my two classes and hanging around the new campus that was hardly built. Dad would be in the lab and I would be running around playing. I played basketball in the gym or I’d hunt for caves in the undeveloped limestone bedrock. In the 1970’s, the place was crawling with horned toads and lizards and snakes – a veritable smörgåsbord for the school’s mascot, the roadrunners.

Most of these species, including the roadrunner, have been made locally extinct in the area by the development of the 30,000-student, fulltime University that UTSA has become. Things change. Even the obliquity of the ecliptic, which is now about 23.4° but currently decreasing 0.013 degrees (or 47 arcseconds) every hundred years.

I didn’t realize how precious that time was to me, and the nature lover I became, until just now, thinking about that summer and the Astronomy class where I learned about the tilt of the earth – which I observed today at noon in Amsterdam in the long-shadowed, exaggerated evidence of the obliquity of the ecliptic: