The prototypical Caltech trio of (left to right) Tom Soifer, Keith Matthews, and Gerry Neugebauer takes a break at the Palomar Observatory in 1978. They would have to wait many more years before seeing infrared images like the one above of Comet 73P/Schwassmann-Wachmann 3, taken by the Spitzer Space Telescope on April 1.

Infrarednecks

How Three Caltech Alumni Helped Take Infrared Astronomy from the Farm to the Major Leagues

By Michael Rogers

These are heady times for infrared astronomy. As the Spitzer Space Telescope orbits overhead, hardly a week goes by without some provocative new piece of data, often accompanied by a glorious image, emerging from a cornucopia of cosmic heat and dust. The fact that infrared radiation (some of which humans perceive as heat) is able, unlike light, to escape from the interstellar and intergalactic dust that shields some of the most interesting and beautiful objects in the cosmos explains this heat-seeking mission’s appeal to astronomers and lay public alike. To date, the Spitzer Observatory, less than a meter in size, has turned in a sellar performance. It has detected evidence of planetary formation in the stark, inhospitable neighborhood of a dead neutron star; directly detected the heat from planets orbiting other stars; identified “molecules of life”—otherwise known as hydrocarbons—that were present in the cosmos when it was one quarter its current age; and in general reiterated what new astronomical observations are always telling us—that the universe is an infinitely richer and stranger place than we already knew it to be. All this from a mission that on one occasion was canceled outright and later, as a last-ditch compromise, was downsized 75 percent before finally being launched in August 2003.

But infrared astronomy has always had an exceptional capacity to surprise. When Caltech astrophysicists produced the first infrared sky survey 40 years ago, using ground-based infrared detectors knocked off from military hardware, they opened an astonishing and previously unsuspected window onto the universe. A decade later, when balloon- and then satellite-borne infrared telescopes were launched above Earth’s obscuring atmosphere, hundreds of thousands of additional new infrared sources were uncovered, including galaxies emitting huge amounts of infrared energy, incandescent regions of star formation within and beyond our own galaxy, and the first tantalizing hints of planets orbiting other stars.

While many astronomers, astrophysicists, and engineers have contributed to the advancement of infrared astronomy, much of the credit for unveiling the infrared sky belongs to a small constellation of Caltech scientists who also happen to be Caltech alumni. For more than 30 years, they have worked together as a team, designing and building instruments, making pioneering observations, planning and operating facilities, and educating and mentoring a new generation of astronomers.

The mainstays of the group are Gerry Neugebauer, PhD ’60, the Millikan Professor of Physics, Emeritus; Tom Soifer ’68, professor of physics and director of the Spitzer Science Center; and Keith Matthews ’62, member of the professional staff in physics. Each has unique skills that have contributed to the development of infrared astronomy. And while Neugebauer is now retired, Soifer and Matthews continue to work together and to consult with Neugebauer, former director of the Palomar Observatory and former chair of Caltech’s Division of Physics, Mathematics and Astronomy. And with the help of today’s sophisticated instruments, including the Spitzer Space Telescope, the telescopes at the W. M. Keck Observatory in Mauna Kea, Hawaii, and the Palomar Observatory, they continue to produce increasingly detailed and dramatic pictures of the universe.

Neugebauer, Soifer, and Matthews are certainly not the only major players in infrared astronomy to come out of the Institute. The late Caltech physicist Robert Leighton ’41, PhD ’47, collaborated with Neugebauer to build Caltech’s first infrared survey telescope, used on the Two Micron Sky Survey at Mount Wilson in the mid-1960s. Other prominent scientists who have worked in Caltech’s infrared group include Eric Becklin, PhD ’68, chief scientist and director designate of the science center of the Stratospheric Observatory for Infrared Astronomy, an airborne telescope set for flight testing later this year; Steven Beckwith, PhD ’78, former director of the Space Telescope Science Institute, which runs the science operations for the Hubble Space Telescope; and Stanford physicist and Nobel Laureate Douglas Osheroff ’67, who crunched infrared data for Neugebauer as a Caltech undergraduate. But while Leighton passed through the field of infrared astronomy relatively quickly, and other scientists trained by Neugebauer came and went, Soifer and Matthews stayed. Over the years, they became good friends as well as colleagues who—like a seasoned jazz trio—jam harmoniously together.

Where No Astronomer Had Gone Before

When Neugebauer first went to work with Leighton, he recalls, most astronomers thought that they were running up a blind alley. The two had met when Gerry, then a Caltech graduate student in the high-energy physics group, worked with Leighton on a research project that involved using cloud chambers to investigate exotic subatomic particles produced in cosmic-ray decays. After getting his PhD, Neugebauer went to JPL in 1960 to complete his Army service, working on infrared detectors for the military. Returning to Caltech in 1962, he and Leighton got together to adapt the same detector technology for use in astronomy.

“In general, the physics and astronomy faculty didn’t care what we did,” Neugebauer recalls. “The astronomers basically thought we were wasting our time, but they were so busy with Mount Wilson and Palomar and had enough respect for Leighton that they left us alone.”

Leighton and Neugebauer built a 62-inch reflecting dish, followed by an infrared instrument that, as Leighton recalled in a 1986 Caltech oral history interview, was “sufficiently sensitive to be interesting and sufficiently precise to be able to locate objects in the sky.” The duo automated it so that it could rapidly image sources, tried it out on campus, and then brought it up to Mount Wilson in 1965 to begin the infrared sky survey. In 1966, they were joined by Soifer, who was just finishing up his sophomore year. Like nearly every Caltech student at that time, he had entered the Institute with the idea of becoming a high-energy physicist. Still, when his roommate, Ed Groth ’68, encouraged him to take a part-time job helping Neugebauer, Soifer signed on. “The way it worked, they had someone paid to operate the telescope five nights a week,” says Soifer. “Graduate students and undergraduates would operate it the other nights. So, every couple of months, I’d run the telescope.”

The 2.2-micron infrared telescope (above left) was built on the Caltech campus by Gerry Neugebauer and Robert Leighton (left to right, in photo at left) and then brought to the Mt. Wilson Observatory where it was put to use in an unprecedented sky survey. The telescope was eventually sent to the Smithsonian, where it was displayed at the National Air and Space Museum from 1983 to 1997. It is now on view at the museum’s Ivar-Hazy Center near Dulles Airport outside Washington, D.C.

The telescope made a sweep of the sky every hour, and Soifer’s job was to orient the instrument hourly to make sure that it was mapping the proper slice of the heavens. “It was a great experience, working with lots of bright, young, enthusiastic people,” Soifer says. “We worked hard. We’d show up at noon and work till 3 a.m., then go to Tiny Naylor’s and have breakfast. There was a tremendous amount of excitement, and it was an enormous amount of fun.”

Among the most interesting discoveries to emerge from the survey were stars that barely registered at visible wavelengths, but radiated copiously in the infrared. “They were so cool that they were not even red; they were brown,” recalled Leighton. These so-called “dark brown stars” turned out to be old stars that were producing dust in their atmospheres and ejecting it into the interstellar medium. Even more interesting than the individual discoveries was their sheer abundance. “Altogether,” said Leighton, “we found some tens of thousands of sources. These were a lot more than anybody thought we would ever come across.”

“The Two Micron Survey was a path-breaking work in that it was one of the things that made people understand what infrared astronomy could do—what the potential was,” Soifer says. “Until you can look at the sky without prejudice, without bringing in your preconceived notions, you’ll miss the importance of looking at the universe at new wavelengths. The survey provided an unbiased and, at that time, unprecedented view of the sky.”

While Neugebauer, with Soifer in tow, was launching the infrared-astronomy field up at Mount Wilson, Keith Matthews was down on campus, participating in the end-stages of a different chapter in science—the cloud-chamber era in particle physics. He enjoyed working with Eugene “Bud” Cowan, PhD ’48, now a Caltech professor of physics, emeritus. But by the 1960s, the particle accelerators were putting the cloud chambers out of business. “Cloud chambers were horse and buggy stuff, in a way,” Matthews says. “When Fermilab turned on in 1972, one pulse wiped us out.”

From his early days growing up in Staten Island, New York, it was clear that Matthews was a born instrument builder. As a kid, he tinkered with Heathkit projects in his basement, and by the time he got to Caltech, he was more than ready, as he says, “to play around” in a more challenging arena. “I wasn’t ever interested in being an astronomer,” he says, but in 1972, when cloud-chamber research dried up, he went to work for Neugebauer and the infrared-astronomy group, building detectors and other instrumentation for Palomar. Matthews says that he knew Neugebauer a bit, and Cowan may have heard that there was a job available with him, but he doesn’t remember exactly who arranged the switch.

By this time, Soifer had abandoned any idea of a career in particle physics and had decided to throw in with astrophysics. He went to graduate school at Cornell, where he was hoping to get involved in radio astronomy, since Cornell had just built a big radio telescope. But he was assigned instead to an astronomer who was helping to launch the burgeoning field of space-based astronomy. “I learned about what was going on there and got excited about that, exploring the wavelengths that hadn’t been observed before,” Soifer says. Putting telescopes into space would be particularly important for infrared observations, since much of infrared radiation, particularly at longer wavelengths, is simply absorbed by Earth’s atmosphere before it can reach ground-based telescopes.

Soifer spent most of his four years at Cornell building instruments that rode rockets into space, gathering infrared data during suborbital flights that lasted only a few minutes. “No one had done this from space before,” Soifer says. Traveling to New Mexico with his first payload, he watched the first launch at the White Sands missile range. “The rockets shot like a bullet out of the tower at 5 g’s. I thought, ‘There’s no way my payload will survive this.’ But my advisor had said, ‘If it survived the truck drive across the country, it will survive the rocket launch.’ And it did.” Soifer would analyze the data from one launch while building the payload for the next.

After Cornell and a year as a postdoc at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, he was hired by UC San Diego, where he continued to build instruments and carry out observational work, some of it aboard the Kuiper Airborne Observatory—a Lockheed C-141 transport plane that flew with an infrared telescope. Back at Caltech, his undergraduate mentor, Neugebauer, had just been named chief scientist on the new JPL mission to launch the first orbiting infrared telescope, the Infrared Astronomical Satellite (IRAS). Soifer was now an assistant professor at San Diego, but when Neugebauer invited him to come back to the Institute as senior researcher for both IRAS and ground-based astronomy programs, he went. “It was a risky move to give up a tenure-track position, but I was young and foolish,” Soifer says. (He would be named a Caltech professor in 1989.)

The image above, assembled from six months of data taken in 1983 by the Infrared Astronomical Satellite, shows the plane of the Milky Way in the center bright band.

Launched in January 1983, IRAS scanned more than 96 percent of the sky during its 10 months of operation, providing the first view of the infrared universe unencumbered by atmospheric distortions. Encased, as Neugebauer fondly put it, “in a thermos jug filled with liquid helium” (which kept the detectors cold enough to prevent their heat emissions from interfering with infrared observations), the 24-inch telescope was equipped with 62 detectors arranged to look at four different wavelength bands, each keyed to temperature ranges associated with specific astronomical objects or phenomena. “The detectors were extremely sensitive,” Neugebauer told his audience at a 1984 Caltech Watson lecture that presented IRAS’s achievements to the public. “If we had IRAS in California and none of Earth’s atmosphere in the way, and we threw a baseball up high enough in New York City, we could have detected it.”

IRAS didn’t find any baseballs up in space (unless you count the six new comets it identified) and, like its ground-based predecessor at Mount Wilson, one of its key achievements was to document the extraordinary number of infrared objects in the cosmos. It detected about 500,000 infrared sources, twice the number of all previously catalogued astronomical phenomena. “It was the first all-sky infrared survey that probed in the thermal infrared across the entire galaxy and out to a substantial distance in the universe, revealing phenomena never before seen,” says Soifer. Among its highlights, he lists the discovery of ultraluminous infrared galaxies, disks of planetary debris orbiting nearby stars, and some of the best views ever obtained of the early stages of star formation. IRAS also provided unprecedented images of the Milky Way’s galactic center, which is too obscured by gas and dust to be investigated at visible wavelengths; uncovered strong infrared emissions from interacting, or colliding, galaxies; and provided compelling evidence that quasars—the most distant and radiant objects in the universe—are fueled by black holes. “There was such great science,” Soifer says. “Almost too much to enumerate.”

Soifer’s primary role in the mission was to organize and oversee the data-processing component of the project, which was carried out at the Infrared Processing and Analysis Center, otherwise known as IPAC: a JPL-NASA facility based at Caltech. “We needed to process the data a certain way to find individual infrared sources in the data stream,” Soifer says. “It was a complicated and iterative process” that involved building a simulator of the sky survey so the software engineers would know how to handle the data once it actually started coming in. “I was a lot more confident that the data processing would work than that the satellite would work.” But both succeeded, and scientists are still mining the data from the IRAS mission.

Although much of his time was taken up with IPAC, Soifer continued to work with Neugebauer and Matthews on the design and fabrication of new infrared instruments for the Palomar Observatory, as well as carrying out observing runs there. Meanwhile, Matthews had become well known in the astronomical community as a superb instrument builder, and in 1980 he was the only Caltech scientist named to the design committee of what would eventually become the W. M. Keck Observatory.

Matthews had built an infrared camera for Palomar during 1987 and 1988, and in 1989 he started work on a similar instrument for the Keck, which was then under construction by Caltech and the University of California. Quips Soifer, the coprincipal investigator on the project, “It was my job to keep people off Keith’s back. I’d take care of reporting to committees and let Keith build the best possible instrument.”

Tom Soifer and Keith Matthews (Keith is the one in the center photo, communing with a dewar in the infrared clean room) have collaborated for nearly 30 years, developing a deep friendship during that time.

Surprisingly, there were few other teams gearing up at that time to build instruments for the Keck. Matthews’s explanation for this is simple: “It was hard work. You didn’t get much out of it—just enough money to build the instruments. I was very worried, and I wrote a memo saying we should be careful and make sure that at least one of the instruments is ready before the telescope is. It would be very embarrassing to have the telescope just sitting there with nothing to put on it.”

As it turned out, Matthews’s instrument, the Near Infrared Camera (NIRC), was the only instrument completed when the Keck Observatory began operating in March 1993, and when a last-minute problem surfaced, it took all of Matthews’s fabled ingenuity and somewhat cranky perfectionism to resolve it. About a month before the camera was scheduled to be shipped to Hawaii, he discovered that the tank of liquid helium used for cooling the detector was leaking. He tried to plug the hole with different materials, and at one point a pressure hose gave way, spraying him and his lab with an oily film. With time running out, he brought his detector—leak and all—to Mauna Kea, where Soifer and Neugebauer joined him for the first observing run. While his colleagues mapped out the astronomy objectives, Matthews focused on making the balky instrument work.

“I had to pump the vacuum chamber and cool it with liquid helium every day,” he says. “I’d get up at 2 p.m., drive up the mountain, pump it, fill it with liquid helium, stay up there all night for the observing run, go back down the mountain at 9 a.m. for breakfast, then go to sleep and get up again at 2 p.m. to go back up the mountain to pump it again. It was leaking but it was working. You could do that forever, but eventually I brought it back to Caltech and replaced the leaking piece.”

Sensitive enough to detect a candle flame on the moon, the NIRC snapped pictures of what at the time were the most distant known galaxies and quasars in the cosmos. It also revealed that an extremely luminous object discovered by IRAS was actually a quasar hidden behind a galaxy. “This meant that the apparent luminosity was ‘magnified,’ and so the quasar appeared to be 30 to 100 times greater than its actual luminosity,” Soifer says.

In 2001, Matthews installed a second infrared camera on the newly completed Keck II Telescope, which had now joined its twin on Mauna Kea. A more sophisticated imager, NIRC II was designed to work with the Keck’s adaptive-optics technology—a kind of corrective lens system that compensates to varying degrees for the atmospheric distortion of starlight, producing images that are 10 to 20 times better than they otherwise would be.

In his more than three decades in Caltech’s infrared-astronomy group, Matthews has built or upgraded numerous infrared instruments and devices, primarily attached to ground-based optical telescopes. Asked if he has a favorite project, he says, “Not really. Some were more successful than others, but some were a pain, even though they were successful.” Almost sounding concerned that his instruments might experience jealous pangs if they deduced that their creator had a favorite, he adds noncommittally, “You get enjoyment out of doing things.”

His instruments are, for the most part, highly customized to the purpose at hand and frequently one of a kind. “There’s no sense in building an oscilloscope,” he says. “If you can buy it and it works, you buy it. You modify things to work or do stuff that does the job that hasn’t been done. I never build stuff for the fun of building it. I always build stuff for some purpose.

“My bottom line is that I want the instruments to be the most sensitive. I don’t want to make a big telescope into a little telescope” by putting on an inferior instrument or one that doesn’t take full advantage of the telescope’s capabilities. Although he’s not officially an academic advisor, Matthews also routinely helps graduate students on their instrumentation projects, from design through the building and operating phases.

Matthews proudly admits that he’s considered something of a “dinosaur” in the world of astronomical instrument builders. He hates reporting to committees and, all things being equal, prefers to design and build instruments by himself with minimal outside interference. As a result, he has largely stayed away from space-based astronomy, which typically involves huge budgets, multiple oversight committees, and, of course, those mandatory meetings.

Body Heat

In 1984, with IRAS an unqualified success, serious plans got under way to design and launch its successor—a next-generation infrared space telescope dubbed the Space Infrared Telescope Facility (SIRTF). Matthews participated in the early design work, but then, citing obligations to Keck, stepped aside. But Soifer, with his months of IPAC management under his belt, got deeply involved, joining the SIRTF team designing the telescope’s infrared spectrograph. By 1990, NASA had designated SIRTF as the highest priority project for the astronomical community and announced plans to lavish $2 billion on the observatory. But then came the disaster with the Hubble Space Telescope’s warped mirror, and the ambitious plans for SIRTF crashed abruptly back to earth.

“There was a point in 1992 or 1993 when the congressional appropriation language explicitly said that no money could be spent on the SIRTF project,” recalls Soifer. “NASA was still trying to support our development efforts, so they sent money to JPL to study infrared observatories and were very careful not to label it SIRTF. It was certainly a depressing time. We were really concerned that the project might not survive, and the dedication of the science team was really crucial to continue pushing NASA, Congress, and other government agencies to support it.”

SIRTF escaped cancellation, although its budget was slashed from $2 billion to $500 million, a move that Soifer thinks reflected NASA’s new devotion to its “faster, better, cheaper” mantra. To meet the constraints of the revised budget, the SIRTF designers were supposed to eliminate the telescope’s moving parts—all 11 of them—and did eventually succeed in whittling the number down to two.

They also refined the telescope’s cooling system, reducing the components to a size “that allowed the mission to be launched on a much smaller rocket,” Soifer says. “We came out with something more elegant, clever, and cost effective then what we started with.” In 1997, Soifer was named director of the Caltech-based SIRTF Science Center, which operates the science program, data processing, and public outreach for the telescope.

SIRTF was launched in August 2003 and, in December, just after it went into full operation, it was renamed the Spitzer Space Telescope in honor of astrophysicist Lyman Spitzer Jr., the first person to propose putting a large telescope in space. Somewhat larger than IRAS, at 0.85 meters in size, the telescope is equipped with an infrared array camera, an infrared spectrograph, and a photometer-camera, and is expected to operate at full sensitivity for three more years.

The Spitzer Space Telescope (above) nearly fell under the budget ax, but since its launch in 2004, it has produced impressive results. The images below of spiral galaxy M51 show several differences between images taken with Kitt Peak National Observatory’s 2.1-meter optical telescope, and Spitzer Space Telescope’s infrared array camera. The Spitzer image reveals unusual structures bridging the gaps between the spiral arms.

These days, Spitzer seems to produce a steady stream of discoveries, making more headlines than any other astronomical instrument currently in operation. The observatory recently found the first evidence that materials around a dead star might be the ingredients for forming new planets. It surprised astronomers with the discovery of planet-forming disks around two massive stars whose size was supposed to be inimical to planetary formation. It detected light from what may be the earliest objects in the universe—stars more than 13 billion years in age—and it recorded the first emanations of heat from a planetary body outside our solar system.

“To me, the most exhilarating discovery is measuring that thermal radiation of a planet orbiting another star,” says Soifer. “It’s a profound and historical thing when humans have detected directly the light from a planet orbiting another star. We never thought we could do this with Spitzer, and it’s really a tribute to the quality of the instruments and the observatory that we could make this extremely precise observation.

“A lot of running Spitzer is administrative and there’s a lot of management, which are not the kinds of things one generally enjoys,” Soifer admits. “But the science is tremendously rewarding. It’s gratifying to feel that you’re a significant part of what is truly exciting science.”

For Soifer, working with Spitzer is not only about watching other scientists have fun. He gets to carry out investigations with the telescope and has used it to study dust-enshrouded galaxies that were formed when the universe was about 1/3 its present age, and that are 1,000 times more luminous than the Milky Way. “We think these are a new class of extragalactic objects which we’re trying to understand. Most likely they’re quasarlike objects hidden in dust.”

These new observations have brought Soifer back together with Matthews to build a new instrument for the Keck—a near-infrared echelle spectrometer, which will look at the spectra of those unusual extragalactic objects. “Spitzer gave us some information, but the new instrument will answer other questions, like what causes this huge amount of energy to be generated,” Soifer says. “We hope to diagnose the internal physical processes in the objects by finding various spectral features that are characteristic of either bursts of star formation or AGN [active galactic nuclei, thought to usually involve black holes] power sources.” Soifer says he expects the instrument to be operational before another year is out.

The Three Amigos

Scientific collaborations are nothing new, but the synergy between Neugebauer, Soifer, and Matthews is noteworthy for both its sustained level of productivity and its duration. Although Neugebauer, who retired as professor emeritus in 1998, now lives in Tucson, Arizona, he keeps in close contact with his former colleagues, while Soifer and Matthews stay in touch with each other daily, via phone calls, walks around campus, or coffee klatches at the Red Door Café, or some combination of all three. Before Neugebauer retired, the three of them could usually be spotted lunching together, often with a group of graduate students.

Former graduate students have also benefited from the camaraderie of this infrared troika. “I felt like I was part of a family,” says Andrea Ghez, PhD ’93, who today is a professor of astronomy at UCLA. “Gerry was like the father advisor, Tom was like the uncle advisor, and Keith taught me how to observe. He’s not only a brilliant instrumentalist, but a brilliant observer too.”

“I think there is something special about them,” says Alycia Weinberger, PhD ’98, now on the scientific staff in the Department of Terrestrial Magnetism at the Carnegie Institution of Washington. “The fact that they’ve gotten along for so many years is really astounding.”

Like Ghez, Weinberger says that Matthews was integral to her work. “Keith was essential to any infrared project. He liked to be a little obscure. That may have been part of the teaching process, not showing you all the steps and forcing you to think through things. I still talk to him regularly.” And, she adds, Neugebauer set very high standards, which pushed all the graduate students to excel. “He worked long hours and expected the same level of commitment from us. When he was chair of the [PMA] division, he would spend his days running the division, go home for dinner, and then come back to do science at night. We always joked that if he didn’t see us at night, he’d assume that we hadn’t been there the whole day.”

Neugebauer says that the reason that he, Soifer, and Matthews have worked so compatibly for so many years is that they have approached science in the same way. “I think the thing we have in common is that we all have the same attitude to what is ‘good’ science and how to do it versus what is ‘bad’ science and a waste of time.” Asked to explain, he says, “This is very subjective, and the reason Tom, Keith, and I get along is that we agree on what’s important without having to spell it out. Basically, it’s the goal to represent scientific data truthfully and to get the most out of it without embellishing it.”

Their relationship is also marked by a level of mutual appreciation that is somewhat rare in astronomy, which often exhibits a divide between those who build the instruments and those who actually use them. “Typically, there is very much a division between observers and instrument builders,” Soifer says. “Most astronomers aren’t involved in the process of instrument building and just want to know, ‘How can I use the instruments that are available?’ Or if they see someone else’s instrument, they’ll say, ‘I want one of those.’ Most astronomers take whatever is available to them without trying to envision what’s useful.”

If the Caltech infrared group is different, it is perhaps because Leighton, who helped start it all with Neugebauer, loved to build instruments, setting a precedent that allowed other instrument builders/observers like Soifer and Matthews to flourish. Soifer, for one, says that his early involvement in instrument building gave him “a deeper appreciation of the importance of new instrumentation and instrumentalists in advancing the field. My background has given me a greater sense than most observers of the value of new technologies and telescopes in opening new areas of research in astronomy. That is why I enjoy that aspect of astrophysical research so much. A major part of the tension between observers and instrumentalists, in my opinion, is that most observers do not recognize that what they are doing is made possible by superb instrumentalists. This leads to a view that the science is done by the observer, rather than as a collaboration between the instrument and telescope builders and users.

“I think that the creation of new instruments is the heart and soul of observational astronomy,” Soifer says. “You can’t make progress in understanding the universe without building new instruments. Keith is a master instrument builder, but he’s also a user. He understands how it all fits together and how it will be used. He has a real breadth of understanding of hardware and what technology can deliver in terms of making measurements and how instruments interact with the telescope.”

Matthews, who says that Soifer has been his constant sounding board and has made invaluable contributions to many of his instruments, sums up the situation rather succinctly: “Without being able to measure things, astronomy is like religion. Astronomy isn’t science unless you observe. It’s speculation. I concentrated on instruments, which is astronomy too. I think it was [UCLA astronomer Lawrence] Aller who once said, ‘The telescope should get the medals.’”

Characteristically, Matthews also has his own take on the distinction between observers and astronomers, saying, “I’m a plumber, I’m not a high priest.” While he enjoys building instruments, he also likes the more immediate gratification that comes from observing by coming up with “techniques to measure things that are hard to measure” or are unknown.

For all the successes that Neugebauer, Soifer, and Matthews have achieved, there may be a bittersweet ending to their infrared astronomy story, in that the research environment that made their collaborations so fruitful appears to be going the way of cloud-chamber physics. In a sense, infrared astronomy has become a casualty of its own success—so popular that it is now dominated by large-scale projects and staffed by scores of astronomers and engineers at many institutions. All in all, says Neugebauer, it’s taken a bit of the joy out of astronomical exploration.

“Infrared astronomy has become such a part of regular astronomy that the fun of experimenting has gone from it,” Neugebauer says. “It’s true that results are more remarkable than ever. The line between producing exciting results and getting personal satisfaction is, however, impossible to define. What’s missing is not the pleasure of doing something worthwhile—and perhaps even fundamental—but the pleasure—to paraphrase Leighton—of doing something worthwhile and important that no one else is doing, or doing it in a unique way.”

But as long as there are new telescopes, there will be a need for the latest generation of infrared instruments, keeping scientists like Matthews and Soifer in business for the rest of their careers. And with Caltech, the University of California, Canadian universities, and a handful of other institutions joining forces to build an unprecedented 30-meter ground-based telescope (now dubbed the TMT), they could have many years of professional challenges ahead. Faced with that prospect, however, Matthews simply says, “I don’t even want to think about the TMT.” Which, in his idiosyncratic way, means that he’s probably thinking a lot about it.