Dropped from the program

We encounter things that are no longer taught.

Reminded of his graduate school days by a review of his notes, our astronomer pulled out a textbook from his aspirational bookshelf.  Here is where he keeps volumes he intends to get to someday, but which he recognizes will take a significant commitment of time or effort.  It’s not that he’s given up on them, for indeed the membership changes regularly, though rather slowly.

This textbook is a nineteenth-century treatise on Natural Philosophy, what we now call Physics.  Though it covers quite a lot of familiar basic and advanced Physics at what we recognize as an advanced undergraduate level, it also includes matters that are now the purview of Engineering majors, as well as some practical applications (computing the tides, for example).  Our astronomer’s interest in it initially came from a couple of short passages that dealt with the stability of motion.  He used them in his thesis and at least one published paper.  But he recognized that there were large sections that went into detail and introduced techniques that he’d never seen, and might be useful someday, like a diagram called a hodograph.

It of course contains no Quantum Mechanics or Relativity, since they hadn’t been invented yet.  When those were found to be necessary for undergraduate science students, something had to go to make room; and that included the hodograph.  A possible alternative, extending the undergraduate course of study by several years, was impractical.

A similar thing happened in graduate school.  But here it was even worse, since grad students must learn enough of a subject to be able to use it to do things no one has done before, and that frontier recedes very rapidly.  A few years ago a professor of astrophysics wrote a two-volume textbook, The Physics of Astrophysics, to cover the basic necessary material, since there wasn’t time in grad school any longer.  (Those books sit next to the course on Natural Philosophy on the aspirational bookshelf.)

Well, scientists, and astronomers in particular, have been becoming increasingly specialized for a long time.  A William Herschel could design and make his own telescopes, carry out a program of observations, and formulate his own theories based on them.  Later the making of telescopes became something astronomers no longer did, but the task of constructing things resurfaced as the specialty of instrument-making.  Theory generally parted from observation, and those who studied stars separated from those who studied galaxies or planets.  In the last few decades the trend of specialization has been partially countered by the tendency to work in ever-larger groups.  Both trends appear to have no end in sight, though we’ve wondered what that will mean for the future.

But our astronomer still intends eventually to understand the hodograph.