The Day We Found the Universe (36 page)

Edwin Hubble and James Jeans at the 100-inch telescope
(Reproduced by permission of the Huntington Library
,
San Marino, California)

Russell's instincts, it turns out, were very good. Hubble in the end won the AAAS award for extending the boundaries of the known universe. He was informed by telegram on February 7, but the amount he received was cut by half. The young astronomer was told he was sharing the award with another scientist. Parasitologist Lemuel Cleveland of the School of Hygiene and Public Health at Johns Hopkins was also honored for his study of microscopic protozoa found inside the digestive tracts of termites. He showed that the tiny organisms were essential for a termite to digest cellulose. “To scientists,” reported the
Los Angeles Times
, “the infinite and the infinitesimal are merely relative terms, alike in importance.” The Hubbles had just bought an acre lot in San Marino to build their charming new home (designed in the style of a small Tuscan villa) and used the funds to help pay for pruning the live oaks on their property and clearing out the deadwood—a needed renovation for appreciating the fine view of Mount Wilson and the San Gabriel Mountains from their backyard. There at his home Hubble began collecting old books, specifically on the Renaissance years, when the old Aristotelian representations of the universe were crumbling. “If an old scrap of paper, published within the sacred period, contains the names of Copernicus, or Tycho Brahe, or Kepler, or Galileo, [Hubble] hankers after that paper more than a debutante hankers after orchids,” wrote a local reporter. It was an apt hobby for the man who erected his own new-and-improved model of the cosmos.

Why was Hubble able to accomplish this magnificent feat while others were not? In actuality, there were several opportunities to resolve the island-universe controversy earlier. The Cepheids could have been hunted down and observed without the 100-inch telescope. It's somewhat surprising that more astronomers didn't sense the celestial riches to be found in distant space, just ready for mining. Having access to the world's largest telescope was not the essential key to Hubble's success (although it certainly helped). Mount Wilson's 60-inch telescope, erected in 1908, could have done the job just fine. Even the Crossley telescope at Lick had an outside chance. But few were interested in this area of endeavor, and those who did had bad luck. For example, the first person to find a variable star in a spiral nebula was not Hubble at all, but rather Wellesley College astronomer John Duncan. In 1920, while using Mount Wilson's 60-and 100-inch telescopes to search for novae, Duncan found three variable stars within the Triangulum nebula, M33. Over the next two years, he took additional images and also checked other photographs of the region made at the Yerkes, Lick, Lowell, and Mount Wilson observatories from 1899 to 1922 in an attempt to track the variables' periods but was unsuccessful. The data were simply too sparse at the time. And in his report of the find, Duncan refrained from directly linking the variables to the nebula. If he had followed up, the prize would have been his: The faintest variable he saw was later found to be a Cepheid and could have been used to peg the nebula's distance. Why didn't Shapley himself, the world's Cepheid guru, search for these special stars in the spiral nebulae and garner one of the choicest discoveries in astronomical history? It seemed like it would have been a natural progression for him. But around 1910 his colleague at Mount Wilson, George Ritchey, had photographed thousands of “soft star-like condensations” in Andromeda and other spirals, which he figured were nebulous stars in the process of formation. This interpretation suggested that a spiral nebula was simply the early stage of a modest star cluster forming, rather than an entire galaxy. Shapley admitted he was deeply influenced by Ritchey's images at the time, as were many others. Years later, in his autobiography, Shapley also suggested that strict divisions were in place in Mount Wilson as well: Shapley was relegated to the globular clusters and Hubble to the spiraling nebulae. Moreover, his taking the Harvard Observatory directorship distanced him from the thick of the battle.

But in truth, Shapley had basically taken off his scientist's hat and become too wedded to his vision of the Milky Way as the defining feature of the universe. He ignored conflicting data longer than he should have, which kept him from extending his work to the spiral nebulae and beating Hubble to the punch. He saw no reason to search for Cepheids in spiral nebulae, since he had already convinced himself that they were not separate galaxies. He was enormously attached to his Big Galaxy concept and had built his career on it. It's not surprising that he would be reluctant to let his vision be supplanted.

Shapley, in the end, was simply human. He didn't view his ignoring the early doubts about van Maanen's work as a scientific lapse but rather a personal one. “I faithfully went along with my friend van Maanen and
he
was wrong on the…motions of galaxies… [People] wonder why Shapley made this blunder. The reason he made it was that van Maanen was his friend and he believed in friends!” declared Shapley (oddly in the third person). He was also a man who was far too confident for his own good, if a popular tale often recounted at Mount Wilson is true. Around 1920 Shapley allegedly asked staffer Milton Humason to examine with the Blink some photographic plates of the Andromeda nebula Shapley had taken over the preceding three years. After comparing the plates for several weeks, Humason came to notice what appeared to be some variable stars in the nebula, possibly the same Cepheids that Hubble found a few years later. Humason, still in training, used a pen to mark off the suspects on the glass plates and went back to Shapley to show him the results. Shapley, not impressed, patiently explained to Humason why his spots couldn't possibly be Cepheids. Shapley was so certain of his position that he proceeded to take a handkerchief out of his pocket and rub out the marks, wiping the plates clean—not to mention wiping out his chances for further astronomical glory. While Shapley was waiting in 1920 to hear from Harvard about the directorship, he confided to one of his former Missouri professors, Oliver D. Kellogg, that he was frustrated by the university's indecision, since it disturbed his ability to prepare his research program for the next few years. Belying what he later said about there being “strict divisions” at Mount Wilson, Shapley noted that “spiral nebulae” were on his agenda and that “cosmogony” would be his future field. Had Shapley not gone to Harvard and instead stayed at Mount Wilson, he would surely have continued to look for novae in Andromeda, the purpose of his photographic survey, and perhaps come to recognize the Cepheids after all. He might have scooped Hubble. That he didn't only added to the ongoing rivalry between the two Missouri men.

Even decades later, when writing his memoir in the late 1960s, Shapley couldn't let go of the beefs with his rival. “The work that Hubble did on galaxies was very largely using my methods,” he recalled sulkingly. “He never acknowledged my priority, but there are people like that.” But then he grudgingly conceded that Hubble had “made himself very famous, and properly so. He was an excellent observer, better than I.” Hubble was patient.

It was that patience that enabled Hubble to methodically carry out the measurements that eluded earlier astronomers. Others had approached the nebular mystery yet gathered only tantalizing and incomplete hints; Hubble performed the painstaking tasks that closed the deal. That meant searching for stars and novae at the very limit of his telescope's resolving power and using them to measure a distance. Curtis had removed himself from big telescope access; Shapley refused to consider that spirals could be huge stellar systems. Only Hubble pursued the question with dogged effort and even he had been looking for novae at first, not Cepheids in particular. Luck certainly played a small role, but as Louis Pasteur once put it, “In the fields of observation, chance favors only the prepared mind.”

Once the news was out, reporters couldn't get enough of the tall and broad-shouldered Major Hubble, as they often addressed him. He was turning into an accomplished popular communicator. “There is just not one universe,” Hubble told a local journalist about his discovery. “Countless whole worlds, each of them a mighty universe, are strewn all over the sky. Like the proverbial grains of sand on the beach are the universes, each of them peopled with billions of stars or solar systems. Science has already taken a census of nearly ten million galactic systems or individual universes of stars.”

Newspapers vied with one another to come up with the catchiest headline to describe the new cosmic order: “Ten Million Worlds in Sky Census,” “Gigantic Telescope Finds New Wonders in Heavens,” “Mount Wilson Observers Now Study Stars on Newly Found Horizons,” “Distances of Star Systems So Great 18 Ciphers Are Needed to Express Them in Miles,” “Light Registered on Photographic Plates Started Million Years Ago.” A London magazine ranked Hubble's achievement “with the greatest in the history of astronomy. Columbus discovered half of a known world, but Dr. Hubble discovered a host of new universes.” Another droll scribe said Hubble had found “more systems of stars than there are hairs in the whiskers of Santa Claus.”

Hubble had even gained enough fame to be joked about. “Professor Edwin Hubble announces that he has found another universe. Some people never seem to know when they have enough,” said the caption of a
Nation
cartoon.

At lectures Hubble drew record crowds. At one Los Angeles talk, the room was filled to capacity while hundreds more jammed the doorways and windows to listen in. An additional five hundred were turned away. “Astronomy, as a matter of popular interest,” reported the
Los Angeles Examiner
, “joined rank with football and prize fights” that night. When standing on the balcony of Mount Wilson's observatory laboratory one night with a reporter, the two gazing at the lights of the towns below, Hubble was asked how he carried out his work. “It is like looking at those lights,” he replied, “and from them alone trying to tell what manner of people live there.”

From that point on, the nebulae beyond the Milky Way became the sole subject of Hubble's professional life; he scarcely studied anything else—although he did by chance discover “Comet Hubble” in August 1937 while photographing a spiral nebula. When a friend asked him to name Jupiter's moons one day, he could recall three or four but no more. “I am commuting to a spiral nebula, and I forget the suburban stations,” he responded apologetically.

Astronomers had been proceeding outward into space and time on stepping-stones. The first stops were at the globular clusters, followed by a giant leap to the spiral nebulae. The conventional understanding of the universe was changing and very swiftly. Just a few years after Hubble confirmed the existence of other galaxies, Jeans wrote that “astronomy is a science in which exact truth is ever stranger than fiction, in which the imagination ever labours panting and breathless behind the reality, and about which one could hardly be prosaic if one tried.”

The English poet Edith Sitwell, upon a visit to Hubble's home, was ushered into the study, where she was shown slides depicting the myriad galaxies that cannot be seen with the naked eye, galaxies millions of lightyears away. “How terrifying!” exclaimed Sitwell, to which Hubble replied, “Only at first. When you are not used to them. Afterwards, they give one comfort. For then you know that there is nothing to worry about—nothing at all!”

Except, perhaps, what to call them. There was much confusion at first on how to identify the newfound stellar systems. Everyone seemed to have a pet name, including anagalactic nebulae, nongalactic nebulae, star clouds, cosmic nebulae, and island universes. Hubble preferred “extragalactic nebulae,” using it in his lectures and publications rather than the term
galaxies
, the name regularly employed by Shapley at Harvard. “I want to get away from both the words universe and nebula in reference to these objects, as frequently as possible,” argued Shapley. “Therefore I am adopting…the term galaxy, and from that the term inter-galactic space follows naturally.”