First Light: The Search for the Edge of the Universe (22 page)

This required money. His only liquid assets were the three telescopes that he had built at the Red River Arsenal. He put a classified ad in the Beeville paper, announcing three telescopes for sale. A passing stranger saw the advertisement. He was a carnival man. In the 1950s, and earlier, telescope men were figures occasionally to be seen in small-town carnivals, selling crowds a tour through the solar system for twenty-five cents. Gunn tried to explain to the man that you couldn’t see anything through the giant telescope, the one with a lens as big as a salad plate. Sure, the telescope man said, but who the hell in Waco will know the difference? The man peeled a few greenbacks from a roll of bills, and that was the last Jim Gunn ever saw of his first three telescopes. They hit the road with a carnival man.

The greenbacks were seed money for a photographic system that
took Gunn five years to build. In the meanwhile he went to college at Rice University, where he finished the telescopic system during his senior year. The telescope had now evolved into a stark white cylinder loaded with cameras. He had wired the telescope up to a transistorized drive box crammed with electronic gear, including military-surplus parts. The telescope had two cameras: a wide-field camera and a planetary camera. The wide-field camera took wide-angle exposures of deep sky, while the planetary camera took close-ups of planets. People in some cultures believe that the souls of the dead can enter inanimate objects, such as rocks and trees. If this is true, then the spirit of Jim Senior must have entered into this telescope’s exquisite gadgetry, which was as compact and resourceful as Jim Senior’s aluminum egg.

Gunn photographed the Pleiades, the Horsehead nebula, the Veil in Cygnus, the Rosette nebula, and the spiral arms of the Whirlpool galaxy. The images were crisp and dramatic—
Sky & Telescope
magazine ran two stories on Gunn and his pictures. He graduated number one in his class at Rice University, a math-physics major. During his high-school years he had begun dating a Beeville girl named Rosemary Wilson, and shortly after their graduation from college, he and Rosemary were married. They moved to California, where Jim began graduate school at Caltech in astronomy.

At Caltech he became fascinated with cosmology, the science that deals with the birth, life, and death of the universe as a whole object—starting at the Big Bang and ending with the fate of matter. Gunn explored Albert Einstein’s equations of general relativity, which describe, in four dimensions, various possible presents, pasts, and futures for our universe. If Gunn had been a normal human being, four dimensions might have satisfied him, but he could not get rid of a chronic disease, the
cacoethes gadgetendi
, the itch to tinker. On his own initiative he decided that what Caltech needed was a machine to analyze star images in a glass photographic plate. The head of the astronomy program, Jesse Greenstein, gave him a midget darkroom in a basement of the Robinson building in which to build the machine. The room was so small that Gunn ended up prefabricating his machine in chunks
at home and assembling them in the darkroom. (I once remarked to Jesse Greenstein that a darkroom seemed a rather narrow place for someone of Gunn’s ambitions. “Yeah?” he said. “Who’s crapping? If you give these guys too much room, they don’t produce.”) One day Gunn rolled something out of the darkroom on wheels. It was a gray metal cabinet, considerably larger than Jim Gunn, and studded with fifty-four dials. The thing is now known to some people as Gunn’s First Machine. It works in the following manner: You clamp a glass photographic plate into an iron stand. A sensor touches one star in the plate. The sensor picks up an image of the star and feeds it into the machine. The machine analyzes the image and declares the exact brightness of the star. Jesse Greenstein still uses Gunn’s First Machine.

During the summer of 1965, Gunn asked one of his teachers, a gadgeteer named J. Beverley Oke, if he could observe on the Hale Telescope, a rite of passage for young Caltech astronomers. Bev Oke took Gunn to the mountain. Oke worked most of the night in prime focus at the top of the telescope, using an electronic instrument to collect red light from a quasar known as 3C 273. A few minutes before dawn, Oke came down and told Gunn to go up. Gunn stepped onto an aluminum platform that looked like a diving board: the prime focus lift. He hit a button, and the lift rumbled up along the inside of the dome, rising past the shadowed girders of the tube, past the curve of the enormous horseshoe bearing, until the lift came to a halt at the lip of the Hale Telescope. There, suspended in the mouth of the telescope, was a small room: the prime focus cage. This room was not unlike a lidless tin can.

Gunn stepped off the diving board into prime focus. He crouched on a tractor seat. He leaned over Oke’s instrument, which sat in the center of the room. It had an eyepiece that looked downward at the mirror. He put his eye to it and saw a set of illuminated crosshairs. The night assistant uncovered the mirror, and Gunn saw a reflection of the universe, already fading in twilight, and suddenly the room tilted sideways and the tractor seat rolled, while Gunn fumbled with the controls of a starship, trying to catch the quasar known as 3C 273, chasing it down as it set into mist over the Pacific Ocean.

“Those big telescopes are a little like drugs,” Maarten Schmidt once said to me. He had probably spent more time at prime focus in the Hale than anyone else on earth. Schmidt had learned astronomy at the University of Leiden, in the Netherlands, and first arrived in Pasadena in 1956, having recently married Cornelia Tom, who had been a kindergarten teacher in the Netherlands. He and Corrie spent two years in Pasadena. They returned briefly to the Netherlands, and then Jesse Greenstein offered Maarten a job at Caltech. Maarten and Corrie settled in California and raised three daughters there.

A Caltech astronomer named Rudolph Minkowski retired soon after Schmidt joined the Caltech faculty. Minkowski was a supermassive astronomer who had difficulty climbing in and out of the prime focus cage, but he nevertheless had pioneered the study of radio galaxies (galaxies that emitted hissing radio noise). When Minkowski retired, he left behind an unfinished observing program, for the sky was too big even for Rudolph Minkowski. Schmidt, virtually by default, took over Minkowski’s program and found himself looking at radio galaxies.

Isaac Newton (one of the original gadgeteers; Newton invented the reflecting telescope) discovered that if he passed the light of the sun through a prism, the prism would produce a patch of color that ranged from blue to green to yellow to a red as dark as blood. A prism, Newton discovered, broke sunlight into its component colors. Newton had invented spectroscopy, or the decomposition of light, which is one of the central techniques of astronomy. By the use of a prism or a mirror ruled with fine lines, the light of any star or galaxy (since galaxies are made of stars) can be decomposed into a slash of color that goes from blue to red, as Newton did with sunlight. This streak of color is called a spectrum. For the foreseeable future, the decomposition of light is the only way we will touch the stars. To make a spectrum is to collect and analyze a star’s material—photons that came from the surface of the star.

A star’s spectrum is brighter in some wavelengths of color, darker in others. When light from a star is spread into a spectrum, the
spectrum shows black bands—narrow, dark gaps marking wavelengths where little or no light comes from the star. These are called absorption lines. They are caused by relatively cool gases and vaporized metals, near the surface of the star, that absorb light at particular wavelengths, thereby blacking out the spectrum in those particular colors. Certain stars—Wolf-Rayet stars, dwarf emission stars—show bright bands in their spectra; distinct, brilliant colors in which large amounts of light pour from the star. These glowing bands in a spectrum are called emission lines, and they are caused by hot, luminescent gases in and around the star, excited by radiation until the gases fluoresce in distinct colors, as does, for example, the gas in a neon lamp. During the nineteenth and early twentieth centuries, astronomers perfected techniques for picking apart starlight into its component colors. They learned how to identify dark absorption lines and bright emission lines as signatures of various elements—hydrogen, carbon, oxygen, metals. They passed the light of a star through a prism onto a black-and-white photographic plate, thereby producing a black-and-white banded streak. They looked at the bands under a microscope to determine the constituents of the star.

Most light is invisible to the human eye. The total spectrum of light goes from short-wavelength gamma rays, to X rays, to ultraviolet light, to visible light, to infrared light, to microwaves, and finally to long-wavelength radio waves. These are all forms of electromagnetic radiation, and thus they are light. The colors that the human eye can see amount to a razor-thin slice of the total spectrum of light. By the 1950s, it had become clear to astronomers that objects in the sky emitted much light other than that visible to the eye. Radio detectors began to reveal spots of radio emission all over the sky. Antennae in those days were not keen enough to pin down the location of a source; most radio spots were resolved only as blobs of noise, too fuzzy to be linked to any particular stars or galaxies. Astronomers felt the frustration of an ornithologist standing in a forest and hearing birds of unknown species singing in the trees. Listening to the songs of birds, the ornithologist sweeps the trees with binoculars, trying to identify new species. Some birds display themselves, but most remain hidden in the foliage. In an effort to aid the task of identification, astronomers at Cambridge
University in England assembled several lists of radio blobs. The third of these lists, which is probably the most famous, is generally known as the third Cambridge survey of radio sources. At that time astronomers thought that most sources of radio emission in the sky would prove to be either radio galaxies or threads of excited gas left over from supernovas, but nobody could be sure, since most sources listed in the Cambridge radio surveys remained unlinked to any objects that could be seen through a telescope.

In the fall of 1960, Thomas Matthews, a radio astronomer, managed to pin down the location of one radio source, 3C 48. (3C stands for “third Cambridge” and 48 indicates that it is the forty-eighth source of noise listed in the catalog.) 3C 48 was a blue star. Allan Sandage, an optical astronomer, became interested. From prime focus in the Big Eye, Sandage photographed 3C 48 and found strange colors. Measuring the object, he found it to be a point source—an object of minuscule diameter, as seen from earth. It appeared to be some kind of a radio star, or possibly the remains of a supernova. Tom Matthews found more locations for the Cambridge radio sources. Some of them turned out to be radio galaxies, and some turned out to be blue stars. A few astronomers began referring to these objects as radio stars, but in general, the astronomers who were looking at them did not think of them as any one class of object.

Jesse Greenstein decomposed the light of several radio stars into spectra, trying to figure out what they were made of. The light mystified everyone who studied it. They found inexplicable patterns of stripes—emission lines painted on top of a spectrum that glowed brightly at all optical wavelengths of light. The emission lines were soft and wide. They signified a bizarre object: something extremely hot, under enormous pressure, containing clouds of gas moving at high speeds, and evidently made of unknown matter.

Meanwhile, as he grew into Rudolph Minkowski’s job, the young Maarten Schmidt began spending long nights in the prime focus cage at the mouth of the telescope, using an instrument called the Prime Focus Spectrograph to break the light of radio galaxies into streaks on photographic plates. It had a slit that allowed the light of a single galaxy, reflected from the Hale mirror, to pass onto a reflective prism. The prism fanned the light into a rainbow. The
rainbow went into a camera and bounced off a mirror, passed through a lens, and hit a glass photographic plate that was the size of a fingernail. The plate was so small and frail that you could pick it up just by touching it with a fingertip, on which the plate would stick. There were two interchangeable cameras for the Prime Focus Spectrograph. One had a lens made of sapphire, the other of diamond. Ira Bowen, who had directed the final testing and figuring of the Hale mirror, had designed these cameras. One of his designs called for nothing less than a diamond lens
half an inch
across. Bowen had no idea where he would find a diamond that big for a price he could afford, but a quiet investigation led Bowen to a diamond dealer who had been using a flat diamond as a watch fob. Bowen persuaded the dealer to part with his watch fob for very little money, since the stone was too thin to be cut. Bowen gave the fob to Don Hendrix, who went to work polishing it with powdered diamond mixed with Vaseline, and turned the fob into a lens.

Just after Christmas, 1962, Schmidt went to Palomar Mountain for a run in which he planned to take spectra of radio galaxies. On the night of December 27, he spent nine hours gathering the light of a radio galaxy. Toward dawn, with a couple of hours on his hands, he turned his attention to a radio object in Virgo, listed as object number 273 in the third Cambridge catalog of radio sources—3C 273. He had seen a photograph of it. It was not a remarkable object at all—just a faint streak or a cloudy filament that was emitting radio noise. He thought it was probably a thread of excited gas. He prepared to take a spectrum of it.