I liked last Sunday’s episode of Cosmos for a couple reasons. The second reason is what the bulk of the show explored: the process of scientific data collection and analysis, the way simple classification can give way to insight about the reality of what the categories mean – in this case, how stellar spectra reveal both the temperatures of stars and also their chemical composition (or at least of their atmospheres), a crucial link in what has become a very long sequence of chains of evidence about the distance of the stars, their age, and the size of the entire universe. (As well as, of course, the often unsung role women have played in the history of science, a theme examined in Adam Lee’s review of this episode.)
But the first reason was the opening of the episode, about how all human societies invoke pattern recognition to see shapes in the stars (i.e. constellations), which reminded me of my own earliest interest in astronomy. In fact, when I think back on my life and try to identify the key events that led to my interest in science, and in science fiction, I can think of two key events, one for each (and I’m not sure which came first). The science trigger was this: in my sixth grade classroom, at Vanalden Avenue Elementary School in Reseda CA (a typical LA suburban school consisting mostly of bungalows), there was a cabinet beneath a coat closet that contained a row or 20 or 30 copies of a book called A Dipper Full of Stars, a very basic astronomy book. The multiple copies suggested they had been used as a class textbook, though it wasn’t used so during my 6th grade session. But I was curious and asked to borrow one copy and took it home and read it, and it was my first introduction to the sky, the constellations, the planets, and the vastness of the universe (it was up-to-date enough, in that era, to realize that the Andromeda ‘nebula’ was in fact a separate galaxy from our own Milky Way).
(I’ll save the science fiction trigger for another post.)
That led to The Sky Observer’s Guide, a little ‘Golden Guide’ book I must have bought through the school’s book ordering program, and my request as a birthday present for a basic telescope, which was granted. (A 3 1/2 inch refractor, if I recall correctly.) I remember setting it up in the driveway of our house in Reseda, pointing it up toward the sky, and being shocked by the apparent sizes of the stars, before I realized how to adjust the focus knob.
I think the most basic fact that one learns as an amateur astronomer is that the apparent brightness of anything you point your telescope at is no indication of its actual brightness or size; apparent brightness is a combination of actual brightness and *distance*. The planets are bright because they are near. Some stars are bright because they are relatively close (like Sirius). Others (like Deneb) are about as bright as closer stars because, even though they are very far away, they are really really bright. (How do we know they are very far away? A chain of evidence beginning with parallax.)
The Cosmos episode illustrated this nicely – showing how the stars in the sky are moving, how the constellations will change over millennia, how the stars of the Pleiades will drift through the galaxy over time.