The Day We Found the Universe (6 page)

If the full amount required had been raised, Keeler would likely have stayed, not wanting to be disloyal to a town he had come to love. But the campaign fell short (to the relief of his wife, who longed to return to the sunny climes of the West Coast). Yerkes Observatory, in Wisconsin, home to the newest record-holding telescope, a 40-inch refractor, also made him a job offer but could not guarantee a permanent staff position. Keeler, anxious to advance both his research and professional career, at last telegraphed his acceptance of the Lick directorship to University of California officials. It was a time when the United States was finally emerging from its deep economic depression. Hope and optimism were on the rise, as the nation was attaining status as a world financial power, at last surpassing Great Britain in overall worth. Highways were being paved with asphalt, and cities brightly glowed at nighttime, awash in electric light. Telephone and telegraph wires lined urban streets like thick, artificial spiderwebs. Keeler's vocation was carried forward on the swelling tide.

Keeler went back to Mount Hamilton, or the “hill,” as it was affectionately known to its residents, on June 1, 1898, seven years after he had first departed for the East Coast. There he found his new duties resembling that of a small-town mayor. “It [was] like being shipwrecked on an island,” recalled Kenneth Campbell, who had grown up on the mountain while his father, William, was on staff. “The Director of the Observatory was, I would say,…the czar… He had to see that Mrs. MacDonald didn't break her leg on that back step, as well as worrying about spiral nebulae.” By then the complex housed three senior astronomers, three assistant astronomers, a small group of workmen, and assorted spouses, servants, and children, some fifty people in all. If a hostess sent out an invitation for an evening gathering, it was plainly understood: no clouds in the sky, no party. Astronomy always came first. A new teacher for the one-room schoolhouse was hired nearly every year (as she often ended up marrying one of the astronomers). For relaxation, residents took some clubs over to the rudimentary golf course, eight holes laid out by one of the senior astronomers on a stretch of flat land just below the mountaintop. No need for man-made hazards; they were all natural—ditches, ridges, ravines, and rock formations; the “greens” were oiled dirt. Occasionally a ground squirrel would carry off a ball, mistaking it for a tasty nut.

A biologist visiting Mount Hamilton returned to the valley below feeling as if he had “dwelt awhile upon Mount Sinai,…watched the marshalling of the stars and the dividing of the constellations.” Saturday nights were often held aside for visitors, with loaded stages and buggies coming up the mountain sometimes twenty to thirty in procession. Leaving San Jose, the wagons could take up to seven hours to traverse the twenty-five serpentine miles, passing first through orchards of figs, oranges, olives, and peaches. Always in sight during the slow ascent were the observatory's bright white domes. Not until 1910 did the automobile reduce the travel time to two hours.

Keeler resided with his wife and two children, Henry and little Cora, in part of a three-story residence known as the Brick House, just a stone's throw from the main building, where the telescopes were located. The move to Lick decidedly changed his routine. His research was now curtailed by innumerable administrative duties, especially correspondence with university officials, suppliers, prospective students, colleagues, and the general public. “There are no astronomical phenomena expected to accompany, or precede, the second coming of Christ,” he politely responded to one correspondent. In style and temperament, Keeler was the anti-Holden. “No member of the staff was asked to sacrifice his individuality in the slightest degree,” said Lick astronomer W. W. Campbell. “No one's plans were torn up by the roots to see if they were growing… Keeler's administration was so kind and so gentle, and yet so effective, that the reins of government were seldom seen and never felt.”

Science, though, remained Keeler's prime objective in accepting the directorship. He once again had access to large telescopes situated in a premier environment for viewing, far removed from polluted industrial air. He completed his first paper, the spectral analysis of a peculiar star's outer envelope, within a month of his arrival. For this, he used the famous 36-inch refractor. As director, Keeler could have wielded his power and become the prime user of the 36-inch, but instead he made a daring and momentous decision. He decreed that Campbell, who had become Lick's main spectroscopist during Keeler's absence, would continue using the 36-inch to carry out an ambitious project Campbell had already begun, measuring the velocities of the stars. Keeler, to everyone's astonishment, chose to work on something completely different: getting the disreputable Crossley reflector up and running.

Keeler became interested in reflecting telescopes while he was still director of the Allegheny Observatory. He knew such telescopes would be particularly advantageous for carrying out his specialty—spectroscopy. The thick glass lenses in refracting telescopes tended to absorb certain wavelengths selectively (depending on the glass and lens construction), keeping that light from registering on either the eye or a photographic plate. This was a dismaying effect to a spectroscopist, who was devoted to collecting each and every light wave emanating from a celestial object. Mirrors, on the other hand, didn't have this problem. They shepherded all light waves equally, no matter what the color, right to the focus. Moreover, lenses were reaching their maximum size at the end of the nineteenth century; they couldn't be manufactured much bigger than forty inches without getting distorted by their own weight. Mirrors, on the other hand, could be made much larger. In Keeler's estimation, reflecting telescopes had acquired a stigma in the past because they had been placed in cheap, flimsy mounts.

Keeler had seen the power of reflectors firsthand while visiting England in 1896 and attending a meeting of the British Association for the Advancement of Science. There Isaac Roberts, a former businessman and accomplished amateur astronomer, displayed the eye-catching photographs taken with his 20-inch reflector. Roberts had pioneered many of the techniques for taking long-term exposures and was the first to reveal that the Andromeda nebula was a spiral. Photography was then having a tremendous impact upon astronomy, radically transforming its procedures. Holden, right before Lick opened, wrote that astronomers can now “hand down to our successors a picture of the sky, locked in a box.” Observers were able to continue their research at their office desks, analyzing their images with mathematical precision, no longer dependent on crude drawings, hasty notes in a logbook, or the fading memory of their night at the telescope. Changes in a celestial object could at last be accurately monitored, from year to year and decade to decade.

After the palace revolt against Lick's former director, the Crossley had been abandoned. It was the mountain's white elephant. No Lick observer was interested in using the reflector, not a surprising turn of events given its dreadful reputation. Even before Holden left, a staff astronomer had written a long memorandum summarizing what sort of research could be done with the Crossley. The title of his paper broadcasted the answer with unforgiving bluntness: “No Work of Importance.”

Keeler thought otherwise, even though he had never before used a reflecting telescope. He was interested because he was after rare game: the particular stars and nebulae that had eluded previous spectroscopists due to their faintness, and the Crossley's special features were going to allow him to obtain a decent spectrum. The Crossley was not just any telescope mirror; it was the largest of its kind in America, but Keeler faced innumerable engineering problems, which he had to solve before the Crossley would be fully functional. For one, the spectrograph he inherited was so large that it had to be removed from the telescope each time the dome needed to be shut. And the telescope's mounting, originally set so it would correctly track the stars in England, had to be realigned to account for Mount Hamilton's more southerly location. Then there was the need for a new eyepiece, as well as a drive clock to keep the telescope in sync with the moving sky. Chemicals had to be gathered for silvering the yard-wide mirror—silver nitrate, caustic potash, ammonia, and a reducing solution composed out of rock candy, nitric acid, alcohol, and water—and telephone wires extended from nearby astronomers' cottages to the dome, so there would be electric light to illuminate the guidewires in the eyepieces.

Making improvements in fits and starts—three steps forward, two back—Keeler and his associates at last got the telescope operating tolerably in September 1898, just four months after he arrived back at Lick. On the fifteenth of that month he tried out his camera for the first time. His opening target, Altair, the brightest star in the constellation Aquila, was out of focus, but another exposure, east of the star, was better. “The fainter stars look pretty sound, but the brighter ones show irregularities,” he wrote down in his logbook. Two weeks later he took a photograph of the Moon, then nearly full. “Plates are fairly good,” he briefly noted. Inside the Crossley dome, the upper wall was painted black, in order to absorb stray reflections from the sky; the lower half, though, was colored bright red, so Keeler and his assistants could see where they were going in the dark. The whole interior was bathed in the faint glow from a lantern fitted with panes of crimson glass, as the photographic plates were not sensitive to red light. Such precautions were essential since the Crossley mirror was held by an open framework of iron rods instead of mounted within an enclosed tube.

In late fall Comet Brooks appeared in the sky. This led to Keeler's first research paper based on his observations with the Crossley. His images, taken over eleven consecutive nights with the help of his assistant Harold Palmer, displayed finer details than previous photographs of comets. They even captured a double nucleus. “On the negative of November 10, obtained with an exposure of 50 [minutes],” reported Keeler, “the head of the comet is made up of two clearly separated nebulous masses, surrounded by the nearly circular coma…. I am inclined to believe that the division of the nucleus was real.” Keeler was not the first to discern such cometary structure, but it was exciting nonetheless.

He soon was observing the Pleiades, the impressive cluster of stars (the “Seven Sisters”) situated near the constellations Taurus and Orion in the autumn nighttime sky. Taking a series of photographic exposures, sometimes lasting longer than an hour, he was able to show that the Pleiades is embedded in filamentary and diaphanous clouds of gas. “Nebulous wisps…are characteristic of the region,” he reported. He later wowed astronomers with a spectacular photograph of the Orion nebula, convincing them of the capability of a reflecting telescope to bring out features formerly too faint to discern. The stunning image served as the frontispiece for an issue of the
Publications of the Astronomical Society of the Pacific
, and it amazed even him. “The photographic power of the Crossley reflector on a fine night is surprising,” he wrote, “at least to one who has hitherto worked with refractors only.”

Keeler went on to use the Crossley to record other arresting celestial sights, such as the sinuous and radiant strands of the Lagoon, Omega, and Trifid nebulae. “We know them so well today,” Osterbrock pointed out, “that it is hard for us to realize how sensational his photographs were to the astronomers of his time… They showed much more detail than even the best drawings of the earlier visual observers.” Keeler was generating the Hubble Space Telescope pictures of his time.

Outside his duties as Lick director, Keeler was spending all his available time on Ptolemy Ridge, becoming the world's expert on nebulae. “The [Crossley's] workmanship is poor and the design is clumsy, but on a fine night the photographic power is quite extraordinary. It has seemed to me worth while to devote some time to ordinary photography of nebulae, as nothing that I have yet seen in this line comes up to what I can get with the Crossley,” he told a friend.

The week before and the week after the new Moon, when the lunar orb was in inky shadow, were his best viewing times. Only then was the sky dark enough to photograph the faint nebulae he was beginning to detect, without interference from a bright lunar spotlight. When the night was clear and calm, he often had time to take several exposures. But then there would be stretches, even when the sky was cloudless, when the wind was so strong that the Crossley shook on its mount, ruining his observation.

Keeler at last got around to his first spiraling nebula on April 4, 1899. He started off with one succinctly named M81, situated in the constellation Ursa Major, just above the “pot” of the Big Dipper. He carefully tracked it from nine until eleven o'clock that evening, as two hours were needed to gather enough light to record an image on the plate. Once the plate was developed, he right away noticed a faint spiraling but considered it “valueless.” A misalignment of the telescopic axis had unfortunately led to the stars appearing as small arcs.

His luck was better the following month. With the Crossley fixed, he took several photos of M51, known as the Whirlpool for its wondrous view of the spiraling, face-on. Keeler's four-hour exposure captured aspects of the nebula never before seen, largely due to the steady air above Mount Hamilton. Keeler sent a transparency of this exposure to his friend George Ellery Hale, director of the Yerkes Observatory, where it took Hales breath away. “Everyone in the Observatory considers [this picture] to be far superior to anything of the kind they have ever seen or expected to see,” Hale responded enthusiastically.

There was something even more consequential in the image, although Keeler didn't appreciate the import right away. Surrounding M51 in the picture were seven more nebulae—though smaller and fainter. In a brief note to the Royal Astronomical Society in London, he listed the exact locations of these nebulae and described them. Some were round, others spindle-shaped or elongated. And that was only the beginning. “Several other faint nebulae, the positions of which were not noted, were observed during the search,” he wrote. “In fact, this region seems to be filled with small, apparently unconnected nebulae, large numbers of which would doubtless be revealed by long-exposure photographs.” It was a fascinating find, but he just assumed it was an uncommon grouping of nebulae, likely confined to that sector of the sky.