Clyde Tombaugh


Hence the pizza!  Nice of the NY Times Op-Ed page to allow me a little room to celebrate what would have been Clyde Tombaugh’s 105th birthday.

A blogger at the Philadelphia Area Center for History of Science has been writing about the Planet X story lately; in his most recent post, Darin points out that in the initial announcement in 1930, V.M. Slipher went out of his way to credit Percival Lowell for leading the way to the planet’s ultimate discovery — while underplaying Clyde Tombaugh’s central role in the painstaking photographic search.

The extension of credit to Lowell, and the relative under-recognition of Tombaugh, could suggest that Slipher simply knew where his bread was buttered.  You give credit to the man with his name on the letterhead, after all, not the undereducated farmboy from Kansas.  And part of the mission of Lowell Observatory was to rehabilitate the reputation of its founder, who was thought to be a bit of a kook.

(For example, Lowell had believed passionately in the existence of a Martian civilization — sustained by an elaborate series of canals.)

It’s worth noting that Slipher’s relationship to Lowell — and the Lowell family — was (understandably) a complicated one. By 1930, Slipher’s old friend Lowell had been dead for fourteen years. Constance, Percival’s widow, had been a thorn in Slipher’s side since the astronomer’s death, spending more than a decade fighting Lowell’s multimillion-dollar bequest to his own Observatory and cutting the astronomers’ salaries in the bargain. On the other hand, once the Planet X project got underway again in 1928, the Lowell family (apart from Constance) invested substantially in the equipment needed, including the remarkable triplet lens the 13-inch astrograph required. It can be imagined that the family expected results from their investment, and that Slipher’s emphasis of Lowell’s role in the discovery of Planet X was indeed at once an acknowledgment of his old friend’s ancient, originating ambition and a recognition of the family’s more recent, crucial involvement.

But consider another line as well. Slipher — and others involved in the Planet X search — knew they had an unusual case in Pluto.  Even before announcing their discovery to the world, they had tipped to the notion that Lowell’s calculations had not in fact been borne out by the discovery of Planet X, because it was too small to have been detected mathematically.  Still, one can imagine Slipher and the others being reluctant to get in the way of a good news story.  We don’t know who wrote “confirmed” here in the headline, but I bet Slipher didn’t protest too much.

Note that this question should be distinguished from the matter of whether Planet X should have been called a “planet” to begin with.  What other word would have fit?  Though its exact dimensions weren’t clear, it was still thought to be a fairly large object.  Certainly it was no asteroid.

The Tombaughs were farmers of wheat and oats; together with other farmers in Pawnee County, they were part owners of a great steam tractor and thresher, like the one here below (I couldn’t find a picture of the Tombaughs farming).  Clyde Tombaugh was responsible for some of the maintenance on the thresher, and some of the same equipment he used for grinding his lenses he also employed in the sharpening of the thresher’s many blades.  The meticulous, umcomplaining work he did around the farm would surely be of help to him later, when he was poring over the endless photographs of the night sky, looking for the one moving speck that would be Planet X.

thresher

The steam tractor provides the power for the great whirring thresher belts while you rake the cut wheat and gather it into your arms and throw it into the thesher mouth, to be separated grain from chaff.  After an hour of standing beside the roaring machines, gathering the cut wheat into your arms, bending and standing, raking and kneeling, you stop hearing the engine, you stop thinking of hearing as something you do, and then all at once the noise emerges again into your consciousness, full of its many constituent parts, a rumble and a liquid pounding and a million high whinnying sounds from the belts and other things besides.  You feel it in your sternum in a strangely personal way.

A fascinating post here braiding together the lives of Clyde Tombaugh, Venetia Burney, and the unusually named Plato Chan.  Born on March 14, 1930, he was supposed to be named Pluto, as it happens — and he would come to his own early fame, as Peter Sieruta points out.  Influences and perturbations indeed!

Plato (Pluto) Chan, winner of the Caldecott at age 12

It’s hard to believe, but Clyde Tombaugh really did make his own telescope essentially from scratch.  In an effort to try to understand how this was actually done, I hunted down old reference guides that would make the process plain.  These images are from 1001 Celestial Wonders, published in 1931.  For a complete account of the step-by-step procedure, and for a description of the materials Clyde might have made use of, go here.

Somehow, when you grind two glass blanks against one another, one goes convex and the other goes concave.  I honestly don’t entirely understand this myself, even after reading about it extensively.  But it works.

In the novel, Clyde does a fair amount of this work, especially early on, as he’s making the telescope that will get him, eventually, to Flagstaff and Lowell Observatory.

Clyde’s grinding post must have looked very much like this.  In the stained glass window rendering here, you can see all these elements.

In the archives of Lowell Observatory, under the excellent guidance of archivist Antoinette Beiser, I came across this typewritten memo – in its original, a few pages long.  While it’s not clear who composed this note, someone has penciled “VM?” in the upper margin — Vesto M. Slipher, director of the Observatory.

In this memo, Slipher (probably) is acknowledging that there was some delay in the announcement of the discovery of Planet X (later Pluto).  Clyde Tombaugh found the retrograding trans-Neptunian object on February 18, 1930.  Lowell Observatory didn’t announce their findings until March 13.  This happened to be Percival Lowell’s birthday — as well as, through one of this story’s many cosmically-arranged coincidences, the date on which Uranus was first discovered.

Aside from the pleasing timing, why the delay?

As I’ve written here before, the astronomers at Lowell weren’t sure what they had.  The object was too small to be the gas giant they’d been expecting.  But their mathematics seemed to indicate that a gas giant was indeed what was out there to discover; only a very large planet could perturb the orbits of Uranus and Neptune in the way that was posited.  So they were understandably puzzled to have found a very small object in just the place that Lowell’s mathematics suggested a gas giant would be.

But what’s of interest to me in this memo is the phrase “In view of the unusual character of the discovery into which the institition [sic] and its founder had given so much in the way of effort and time we had to be content to allow the momentary gusts of emotion to blow over…”

One way of reading this goes: we’d been looking for the thing for so long, and under such pressure to find something, that we wanted to make sure we had something genuine before we said anything.

That’s a legitimate reason to hesitate, of course.

But I think, too, that it’s fair to read those three weeks as a pregnant pause, during which the astronomers decided whether to call this object Planet X or not — that is, whether the accumulated pressures of history and institutional expectation outweighed the obvious problems with the object.  It wasn’t what they were expecting.

So – should they gamble?  Should they go ahead and try to call this object Planet X?

Had it been a gas giant — had they found what they’d been expecting — I bet they would have announced it the next morning.  Instead, over the next three weeks, they took countless photographs of the object, hoping to solve their conundrum.  They never did.  And in the end, of course, they didn’t call it Planet X when they finally announced it.  They just called it a “solar system object apparently trans-Neptunian.”  It was the press that called it Planet X, and so a planet was born.

According to what I can find, the astronomer Kenneth Newman arrived at Lowell Observatory shortly after the discovery of Planet X in 1930.  At any rate, he begins to publish articles and to appear in Observatory photographs around 1932.  It’s nice to think of Clyde having someone to work closely with — someone around his own age, I mean.  And it’s a little eerie to see Newman here in this photograph, seemingly playing the part that the fictional character Alan Barber does in Percival’s Planet.

It strikes me that astronomy in that era — with its long periods of nocturnal solitude — could be awfully lonely labor; I imagine Clyde found it a relief to have somebody else around.


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