First Light: The Search for the Edge of the Universe

by Preston, Richard

  Professor Schorr gave him a basement room for a workshop, but der Optiker appeared to spend much of his time wandering around Bergedorf while talking to himself, apparently drunk, and puffing a tilted cigar under a brown felt hat pulled so low over his eyes that people feared he would catch the brim on fire. Der Optiker was terribly secretive. He allowed almost nobody to enter his underground vault. Opticians do not mix easily with humanity. As Mel Johnson, the optician who did some of the final figuring on the Hale mirror, explained to me, “All that scratching and dirtiness with people, it just kills you off.” The optician fears that people will feel the glass, and who knows where their hands have been. People will scratch their scalps, putting dust into the air, which can get between a polishing tool and the glass. One time, unbeknownst to Schmidt, a visitor picked up a polishing tool and took a few strokes with it on one of Schmidt’s mirrors, removing about a tenth of a millionth of an inch of glass. When Schmidt tested the glass, he saw skid marks where the visitor’s tool had touched down. “Somebody has been fooling around with this!” he screamed. Professor Schorr always felt that Schmidt’s real skill as an optician lay at least as much in his eyes as in his hand, for when Schmidt looked at glass through his testing instruments, he could tell instantly where it deviated from a perfect optical surface.

  Schmidt had such respect for glass that he dressed himself in a formal morning suit (a man’s long-tailed wedding suit) before he entered his polishing chamber. He hung a straw boater hat on a nail, revealing cropped, graying hair. He stood over a disk of glass and walked slowly in circles around it, watching the glass with a stern expression on his face, stroking the glass now and again with a small figuring tool faced with pitch, and kept his cigar stub unlit or let it burn in an ashtray to prevent ashes from dropping on the glass. His left hand looked like the hand of Michelangelo’s Moses—gnarled, monolithic, nourished with blood vessels. He knew the superiority of his hand to any polishing machine. “My hand is more sensitive than the finest gauge,” he said. His mirrors rested on bizarre contraptions made of crates and boards and ropes and pulleys. He refused to tell the world how he shaped his glass. “If I were to write it down,” he said, “it would so shock the astronomers and the opticians that I’d probably never get another order to construct anything.”

  In the summer of 1929, an eclipse of the sun happened in the Pacific Ocean, and the observatory dispatched Bernhard Schmidt and a young astronomer named Walter Baade to the Philippines to photograph it. They left Hamburg in February on a steamship and did not return until September. The eclipse was blanketed by clouds, ruining some of the observations, which seems a pity for Schmidt and Baade after such a long journey. During the trip Baade snapped a photograph of Schmidt. In it Schmidt has no arms at all. Schmidt had hidden his one arm behind his back, because he was holding a bottle and he didn’t want it to appear in the photograph. The expedition’s main event, at least for the history of astronomy, took place on the steamship somewhere in the Indian Ocean.

  Walter Baade never wrote much, but he left some stories with friends. What happened went something like this. It was evening, as Baade later recalled. While Baade did not describe the setting, I think it is likely that the two astronomers were standing at the rail of their ship, watching a dark tropical sea slide past. The air would have been so clear that the stars contacted the horizon. Under the spell of the Clouds of Magellan, der Optiker would have steadied himself at the rail with his hand and remarked, around a fresh-lit cigar, that he had thought up a design for a telescope.

  Walter Baade listened.

  This telescope, Schmidt said, would be able to photograph a huge area of sky in a single exposure, and the star images it rendered would be needle-sharp from edge to edge on the film. It would be a very fast telescope.

  Baade sensed that Schmidt had been thinking about this for a while.

  First, Schmidt said, he would grind a mirror into a deep, hollow, spherical curve. That was easy—any two-fisted optician could achieve a spheroid. The reason that nobody used spherical reflectors in telescopes was that they produced horrendous distortions across the entire photograph, making such mirrors useless for astronomy. But what if one could install a correcting glass on the snout of the telescope, to reshape the light falling on the mirror? The correcting glass, Schmidt said, would have a toroidal ripple in its surface, an undulation so subtle that the glass would look to the untrained eye like a piece of flat window glass. But it would not be flat. It would introduce subtle distortions in the light. When the light bounced off the spherical mirror and hit a piece of film in the center of the telescope, it would be in complete focus from edge to edge of the photograph.

  Baade was stunned. The potential of such a telescope must have been immediately obvious to Baade: it could be used to search the sky for moving objects. Baade told Schmidt that he must grind one of these corrector glasses as soon as possible.

  Noch nicht! Schmidt said. Not yet! First, he said, he must think up a method to polish his corrector glass. He would never, never, do a sloppy job on a piece of glass. Never! The praxis, the technique, he said, must be sehr elegant.

  When the expedition returned to Germany, Baade and the observatory’s director, Professor Schorr, began to press Schmidt to make his corrector glass. Schmidt answered them by walking calmly and aimlessly around Bergedorf, drunk, threatening to catch his hat on fire with his smoldering cigar. “Above all, he valued his independence,” recalled Baade. Abruptly Schmidt took off for the Island of Women. At some point—it is satisfying to think that it might have happened while Schmidt was tramping around those fields where he blew off his arm—he dreamed up another of his bizarre machines for polishing glass. He returned to Bergedorf. To Baade he remarked that he needed to know something about the bending characteristics of a thin sheet of glass. Baade gave him a handbook of physics. Schmidt studied the book and then donned his wedding suit and shut himself in his vault. He wanted nobody to see what he did.

  When Schmidt had been in his vault for thirty-six hours, Baade began to worry about him. Baade finally went downstairs and found Schmidt unconscious near a wafer-thin, fourteen-inch disk of glass. “On waking,” Baade said, der Optiker “accepted cigars but declined coffee and sandwiches,” because, Schmidt said, he still had twelve hours of polishing left to go. Schmidt smoked a couple of cigars and shooed Baade out. The work climaxed in a frenzy of polishing.

  The finished corrector glass was so thin that a pull with a pair of hands could have snapped it. As for his “elegant method,” Schmidt had placed the glass on a pan, like putting a lid on a cook pot, so that it formed a seal. He then pumped the air out of the pan while the glass bent downward and was sucked into the pan. He polished his glass flat, released the vacuum, and the glass popped up into a rippled shape. Sehr elegant!

  By the summer of 1930, Schmidt had built a telescope to house his glass. One muggy Sunday afternoon he took Baade up to an attic window in one of the buildings at the Bergedorf observatory for first light. Ordinarily it is not possible to look through a Schmidt telescope by eye (the light comes to a focus in the center of the tube), but for this occasion Schmidt had evidently rigged up some kind of a prism to bring the light to an eyepiece. Schmidt pointed the telescope across a wide meadow, toward the Neuer Friedhof cemetery.

  Baade squinted into the eyepiece. Baade noted a clarity of colors. He noted that the edges of the leaves on the trees in the cemetery were razor-sharp.

  “Can you read the names on the tombstones?” Schmidt asked.

  “Yes,” Baade said, in awe. “But I can see only one thing: the optics are absolutely marvelous.” Baade then asked Schmidt just how big a corrector glass could be ground.

  Forty-eight inches across, said Schmidt. Not any larger.

  Then they put film in the telescope and photographed a tombstone. The letters of the name were clear.

  That summer and autumn, Schmidt photographed the sky. Light passed through the glass, down onto the mirror, and bounced halfway b
ack up the tube until it came to rest on the film—a simple and powerful imaging system. The films were circular and spangled from edge to edge with veldts of the Milky Way. One winter night he and Baade pointed the telescope horizontally and made an exposure of a windmill two miles away. The sails came out crisply. When they looked at the photograph through a magnifying loupe, they could count individual twigs on distant trees. As a matter of fact, it was a moonless night; the twigs had been illuminated by starlight.

  The Bergedorf observatory was immensely proud of its new telescope. But when der Optiker offered to build Schmidt telescopes for other observatories, nobody wanted one. He lowered his price to a pathetic sum. No other observatory in Europe would touch his camera, the fastest telescope on earth. Der Optiker grew loud and resentful in the taverns of Bergedorf. When he had taken a lot of brandy and had become what he called drunk “auf Achse” (“drunk to the axle-shaft”), he would order a round for the house and proclaim, “The whole world is going to hear of Schmidt someday!”

  The 1930s in Germany were not a good time or place for a one-armed Estonian with a criminal record for pacifism. Schmidt smelled another war coming, which made him extremely angry, and so he contrived a method to escape the war: he began to thoroughly rinse his bloodstream with expensive cognac—an elegant praxis—and it worked. In the winter of 1935, “Death took the polishing tool from his hands,” as one of Schmidt’s colleagues wrote, referring to Schmidt’s “hands” in the plural, seeming to forget that Schmidt only had one hand. They buried him in the same cemetery that he and Walter Baade had photographed while testing the first Schmidt telescope. It is the Neuer Friedhof cemetery in Bergedorf, near Hamburg. If you happen to visit that graveyard, I recommend that you turn through the right-hand door at the main entrance of the cemetery and follow a ring path until you reach a magnolia. You will now be standing among the very tombs from which Baade and Schmidt took first light. There you will find der Optiker’s own grave, which is a dark headstone engraved only with his name, a star, and the words PER ASPERA AD ASTRA.

  In 1931, Walter Baade joined the staff of the Mount Wilson Observatory in Pasadena, bringing with him the photograph of the tombstone that he and Schmidt had taken, as well as some photographs of the night sky. These greatly impressed George Ellery Hale and everyone who saw them, including a Caltech physicist by the name of Fritz Zwicky. Soon afterward, Zwicky collaborated with Walter Baade in a great discovery—they found that stars can explode with extreme violence. They used the word supernova to describe the explosion. Fritz Zwicky longed to watch a supernova go off. A supernova is a rare event, and Zwicky realized that he would be unlikely to see a supernova anytime soon inside the Milky Way, but he figured that with a wide-field telescope he could monitor a large number of galaxies and perhaps thereby raise his chances of seeing the gleam of a supernova. A Schmidt telescope would be perfect for a supernova search. Construction of the two-hundred-inch telescope had barely begun on Palomar Mountain, but Zwicky began badgering opticians and engineers at the Mount Wilson Observatory and at Caltech to build him a telescope. The result was the eighteen-inch Schmidt telescope, or Little Eye, now used by the Shoemakers to search for comets and asteroids. Russell Porter, who styled some of the details on the Hale dome, designed the eighteen-inch telescope’s aerodynamic lines.

  First light hit the mirror of the Little Eye in 1936, when Fritz Zwicky began photographing swarms of galaxies in Virgo, hoping to catch an exploding star. He had luck. He found supernovas popping off in galaxies all over the sky. Zwicky’s eighteen-inch Schmidt was the first telescope on Palomar Mountain, and the only one there for the next twelve years, until the Hale Telescope went into operation.

  In 1947, the forty-eight-inch Palomar Schmidt Telescope saw first light. This telescope was Walter Baade’s jewel. He had supervised its construction. It had a corrector glass of exactly the largest size that Bernhard Schmidt had said would work, that summer afternoon in Bergedorf. When Baade’s telescope went into operation, Zwicky’s little Schmidt dropped into obscurity inside a thicket of carrasco oaks, and Zwicky began to feel ignored by his colleagues and especially by the press. He began to feel that the other astronomers, Baade in particular, did not want him to use the Hale Telescope. Zwicky probably did not help his requests for time on the Hale when one night, when he was working at the forty-eight-inch Schmidt, he ordered a night assistant to hurl a series of cherry bombs out of the dome, hoping that the explosions would improve the seeing. The seeing did not improve, but the noise and flashes, which made it sound as if Zwicky had started a war near his telescope, did not encourage the other astronomers to let him use the Big Eye.

  Zwicky began to remark loudly that he had built the first Schmidt telescope. Baade reminded Zwicky that Bernhard Schmidt had. Zwicky became irritated with his former collaborator, Walter Baade. Zwicky began referring to Baade as “the Nazi.” That was a cruel joke. Baade was an excitable, rather delicate man, with pointed ears and a bow tie. He limped badly—one of his legs was a good deal shorter than the other—and he stuttered. He was no Nazi. His hands trembled from nervousness, giving some of his colleagues the impression that he was about to come apart at the seams. Yet somehow whenever Baade took the guide paddle of a telescope in his hands, all the shaking stopped, as if Baade were transfixed at the sight of his guide star in the way that a deer can be jacked in a flashlight beam; and then Baade took masterful photographs of star fields that were as fine as powdered talc.

  Zwicky had his own ideas about how to photograph a galaxy: he thought that photographic emulsions should be mixed with explosive chemicals. That way you could point the telescope at a galaxy, open the shutter, and you would hear a little frying sound and a pop inside the telescope when the light hit the film, causing it to explode—now that was what you called a fast film. Zwicky was a maximal space freak. In the early days of rocketry, Zwicky put an explosive charge on the nose of a German V-2 rocket, and when the rocket had reached the top of its trajectory, Zwicky triggered the charge, which fired a scrap of metal off into deep space. Zwicky was proud of that because he, Fritz Zwicky, had sent the first human artifact into escape velocity from the earth. Zwicky held some fifty patents, including one for an underwater ramjet that he called the hydrobomb. He regarded most of the other Palomar astronomers as fools, and Walter Baade as a cretin. Zwicky, who had been born in Bulgaria but raised in Switzerland, believed that he was superior to the others not only mentally but physically. He tried to demonstrate this by doing one-armed push-ups on the floor of the Caltech Athenaeum, a posh dining room on the Caltech campus. There the faculty ate filet mignon and reasoned with one another on scientific topics—and on at least one occasion collectively stopped their forks midway to their mouths while they watched Fritz Zwicky flop to the floor like a bull seal and in a grunty, roaring Swisso-Bulgaric accent, challenge anyone to beat him at one-armed push-ups. The Palomar astronomers could not get rid of Zwicky—he had tenure at Caltech—but they consulted psychiatrists to see if he was edging into psychosis, and the outlook must not have been favorable, because Walter Baade grew physically afraid of Zwicky.

  It was not difficult to feel afraid of Fritz Zwicky. He had a glowering flat face, pale blue eyes, and a savage sense of humor. He would swear torrentially at night assistants, using scientific terms laced with obscenities. He referred to Baade and the others as spherical bastards—“They are spherical,” he said, “because they are bastards every way I look at them.”

  Zwicky was, in fact, a true genius, and one of the greatest minds at Caltech, although his personality kept him in deep trouble with his colleagues, some of whom clearly hated him. He made many discoveries. His most prophetic happened in 1933. Studying the motions of galaxies in the Coma cluster, which is a cluster of galaxies fairly near the Milky Way, Zwicky realized that these galaxies were moving abnormally quickly around their cluster. The galaxies were moving so fast that the whole cluster should fly apart. But obviously the cluster was not flying apart. He concluded that
some kind of powerful, unseen gravitational force was holding the cluster together. He did not know what it was, so he called it the missing mass. For many years astronomers tried not to think about Zwicky’s missing-mass problem (one tried not to think about Zwicky at all), until recently, when astronomers finally could not deny that the universe really does contain large amounts of unseen mass. They now call it the dark matter. And it is a very big problem. They do not know what the stuff is, although they do know that it makes up as much as 99 percent of the universe. In other words, astronomers do not know what most of the universe is made of; and Fritz Zwicky told them so. His discovery of the missing mass is probably the most important problem in modern astronomy. After all, it would be nice to know what the universe is largely made of.

  Zwicky used to say, “Only Galileo and I really knew how to use a small telescope.” According to one astronomer who knew Zwicky, Zwicky seemed to fill up more space than he actually occupied, as if he himself contained missing mass; and Zwicky fully occupied the little dome, slamming the eighteen-inch telescope around, allegedly putting dents on its tube while he looked for exploding stars. Walter Baade began to wonder what would happen if Zwicky went mad. What if he burst out of the little dome and came around to the Hale Telescope one night looking for Walter Baade—and not with any telescope, either? Hands shaking, Baade whispered to colleagues that he believed Zwicky was going to murder him.

  Rumors that Fritz Zwicky was on the verge of murdering Walter Baade got around. During dinners at the Monastery, Baade and Zwicky sat at opposite ends of the table, where they did not speak to each other and hardly to anyone else, although Zwicky’s pale eyes flicked in Baade’s direction, giving some of the diners the need to take an antacid. An astronomer named Milton Humason was often present during those dinners. Humason had begun his career as a janitor and a mule driver on Mount Wilson, and had been promoted to astronomer. Humason had collaborated with Edwin Hubble on the discovery of the redshift of the galaxies and thus of the expansion of the universe, one of the most important scientific discoveries of the century. Humason was a short, humble man who wore a Chicago-style felt hat and a heavy coat that generally came equipped with a pint of Jack Daniel’s somewhere in the coat, for extra protection against substellar cold. Milton Humason was regarded as the kindliest of the astronomers on Palomar Mountain, but Humason had been around mules long enough to know when to draw the line. One night at dinner, Zwicky gave the final proof that he had gone mad. Zwicky said in a loud voice that a rocket ought to be fired at the moon in order to recover moon rocks for study.