Taking It to The Limit

A low, wooded hill separates the northernmost reach of the College's campus--Currier House--from Cambridge's Fresh Pond neighborhood. On that hill, at the fringe of both academia and the real world, sits the Harvard-Smithsonian Center for Astrophysics, housing over 300 astrophysicists--the largest group in the country.

Although the Center grew out of two older observatories, few there spend much time looking through telescopes. Most work at desks in their own offices, surrounded by references, handbooks, or computer printouts. At first inspection, the center seems like the headquarters of some old-boy-dominated corporation. The smell of pipe smoke wafts down many halls. Most of the women in the building work as secretaries or receptionists for male scientist-administrators. They keep the files in order and the coffee warm while the scientist-administrators talk on the phone and move purposefully between offices, checking on the progress of the scientists in their division. The conversation that escapes from some offices centers on administrative details--proposals for obtaining grants and contracts.

But it becomes apparent that the organization is no profit-making enterprise. George B. Field, director of the Center, says instead that the work is "a manifestation of that inquisitive, aesthetic, adventurous side of the human spirit." Below Field's office a grey-haired adventurer wanders distractedly through the Center's library, his untucked white shirt sticking out below his suit jacket. He clutches a protractor in one hand as though he has forgotten it is there, and his mind seems to be somewhere among the stars he is studying. The library where he ponders has no formal checkout desk. No librarians remind borrowers to fill out checkout slips, which simply admonish borrowers to return books as soon as they can. Casual discussions in various offices around the Center concern satellite launching, photon sorting, and ways of measuring gravity waves. A bumper sticker on one office door says cryptically, "Black holes are out of sight," while a door in the basement carries the impressive label "Cosmic Dust, Meteorite, and Lunar Studies Lab." In another basement lab two scientists tinker with an elaborate device that, when finished, will heat molecules so their spectra at temperatures above 2500 degrees Centigrade (4500 Fahrenheit) can be observed. At that temperature even iron becomes a vapor, as it is in stars.

The diversity of research, as well as the Center's size, makes it unique. Field says its $15 million annual budget supports the only working body of scientists in the country that includes all the various disciplines of astronomy--from optical astronomy, to atomic and molecular physics, to theoretical astrophysics. The Center is also unique because it brings together under one roof and one name a department of Harvard's Faculty of Arts and Sciences and a division of a federal agency. The Faculty department is the Harvard College Observatory (HCO). The federal division is the Smithsonian Astrophysical Observatory (SAO), a bureau of the Smithsonian Institution.

Although HCO owns the building and the grounds and SAO pays rent, SAO is the larger of the Center's two parts. SAO's budget totals $11 million yearly, of which four million dollars comes directly from the Smithsonian Institution. HCO has an annual budget of four million dollars, including $250,000 from its own endowment.

Most of each observatory's budget comes from grants and contracts from federal agencies--mainly NASA and the National Science Foundation. Though each of the observatories maintains its own financial and administrative structure, scientists pay no attention to those structures while conducting research. SAO and HCO scientists have offices interspersed on the same halls, and they consult each other without considering which observatory they draw pay from. Many at the Center hold appointments with both groups. Field, the Center's director, is also director of SAO and HCO. But even he cannot delineate exactly where each of the observatories begins and ends. Of his own conference room, Field says, "Who it belongs to, I don't know."

The present arrangement began informally in 1955, when Fred Whipple, Phillips Professor of Astronomy, was appointed director of SAO--then based in Washington, D.C. Rather than move from his Cambridge home, Whipple asked that SAO be moved up to the hill off Garden Street where HCO had been operating since the 1840s. Then Cambridge air was clean enough, and astronomy was young enough, for astronomers to make significant observations without leaving the city limits. SAO had a staff of only five people in 1955, so Whipple got the observatory moved without much trouble. The informal link between the two observatories was formalized in 1973. Field became director of a new entity, the Center for Astrophysics, as well as director of the two observatories that comprise it.

James Cornell, publications manager for the Center, says the combination brings together "all the various tools one needs to attack problems at the very limits." For Marc Davis, assistant professor of Astronomy, the tools include the grant-obtaining power of a Harvard faculty appointment, and SAO observing equipment in Arizona.

Davis is seeking a $60,000 grant from the National Science Foundation to analyze the light from a large number of galaxies--at least 1000, possibly 3000. Davis wants to use that information, combined with some principles of astrophysics, to estimate the mass of the universe, a figure that has implications for the universe's ultimate fate. If the universe, which is now expanding, is massive enough, it will ultimately stop expanding and draw itself back into the single ball from which astronomers agree it exploded.

Davis expects his work to bear out the prevalent belief that the universe is not massive enough to draw itself back together, and will continue expanding indefinitely. But Davis says he thinks "it would be aesthetically pleasing" if the universe were heavy enough to someday stop expanding. Current estimates put the mass of the universe at about one-tenth that necessary to pull everything back together. Davis expects to find a higher estimate, but still only 20 to 30 per cent of the necessary mass.

Davis says his grant proposal would have been rejected out of hand if he were a Smithsonian appointee because the National Science Foundation would not want to fund work in another government agency.

But if the grant comes through, as Davis expects, he plans to work together with a colleague on the SAO staff to develop a highly automated device to take needed data quickly and efficiently. For making actual observations, Davis plans to use the automated device with a telescope at an SAO observing facility.

SAO has an observing station beneath the clear skies of Mt. Hopkins, Arizona, and HCO owns a station beyond the polluted skies of Boston, in the town of Harvard, Mass. The equipment at HCO's station includes a large, optical telescope and a radiotelescope--a movable disk 84 feet across for receiving radio waves from sources in deep space. A reflecting telescope composed of six 72-inch-diameter mirrors should go into operation at SAO's Arizona station this summer, although in Fall 1975 completion of construction was expected by Fall 1976. The six mirrors, focused together by computer, will equal the light-gathering capacity of a 176-inch reflector--second in size only to the 200-inch reflector at Mt. Palomar, Ca. The cost of the multi-mirror telescope, borne partly by the University of Arizona, will exceed five million dollars. The telescope housing alone cost over $1.3 million. Herbert Gursky, the Center's associate director for optical and infrared astronomy, says researchers will use the new telescope to make a systematic survey of quasars--the most distant, fastest-moving objects in the universe. Quasars also emit radiation at vastly higher levels than any other objects, because of their distance from earth. Only a large telescope can detect them. Quasars may provide astronomers with a window on the early history of the universe because their light takes billions of years to reach the earth. Gursky says he expects a survey of the quasars to reveal a great deal about the structure of the universe.

While observers at the multi-mirror telescope in Arizona will study the ends of the visible universe, Alan Lightman, assistant professor of Astronomy, is now reaching for knowledge out at the brink of the unknowable. In his carpeted nine-by-twelve office, Lightman is doing theoretical studies of star patterns adjacent to black holes. Existing instruments cannot observe these patterns.

Black holes are theoretical spherical gaps in space, predicted by the general theory of relativity, from which nothing can escape. Whenever a sufficiently massive star burns out and collapses, a black hole should be created. The collapsed matter should be so dense, and its gravitational field so strong, that within a certain distance it would hold in even light. Once any object, radio wave or ray of light passes within this distance--crosses the black hole's "event horizon"--it is effectively lost to this universe.

Because black holes emit no radiation, they can never be directly observed. Their existence may be deduced only from the extraordinary effects black holes have on nearby objects, outside the event horizon. Lightman is attempting to predict the influence of black holes upon the distribution of stars, anticipating the day when such stellar patterns can be observed.

Some studies at the center are much more mundane. Jack Eddy, a visiting scientist at the Center, has shown how the amount of radioactive carbon in tree rings can be related to sunspots. Increased solar activity leads to warmer climates, Eddy says, raising the radiocarbon content of the rings. Another group of astronomers, working with radio telescopes designed to detect water vapor in remote parts of our own galaxy, found they could also use the radio telescope to measure the amount of water vapor in the earth's atmosphere. The method proved cheaper and more accurate than previous techniques, like taking samples with rocket probes.

The satellite Lageos, conceived and designed by scientists in the Center's division of geoastronomy, may provide a measure of continental drift. The satellite, now in orbit, is two feet in diameter, and is covered with 426 small mirrors. Scientists at two different ground stations direct lasers at the satellite. By precisely measuring the round-trip time of each beam, they hope to determine the distance between the stations to an accuracy of two centimeters--the distance many think Europe and North America drift apart each year. The researchers' accuracy is at about ten centimeters now. But most of the research at the Center looks much farther away from earth.

Field does not attempt to give pragmatic justifications for astronomy, although he does credit astronomy with starting the industrial revolution. He says astronomy provided the realization you could predict natural events--it offered "a few equations that had fantastic implications." But Field chiefly justifies the Center's work in romantic terms: "First and foremost, astronomy is an adventure--an intellectual adventure, but also an aesthetic adventure. Everyone can participate in one way or another." Field says, "Humanity loves astronomy--it's the wonder aspect. People don't wonder about bacteria, or the structure of the nucleus. It's a very primitive thing. I can't explain it, but it seems to be real."

In a convocation speech at the Center last May, Field suggested that astronomy may soon arrive at a major "intellectual synthesis"--"With an impact rivalling that of the Darwinian theory of biological evolution, it may be able to account for all the structures in the universe, from quasars to planets." Gursky, in the office above Field, is not so confident. He says, "If we thought we'd find an answer, we'd give up. We'd just publish it and go home."

In the meantime, research at the Center goes on, and the universe continues to expand. If you want to know what is happening in the sky this week, you can call the Center's Dial-a-Satellite phone, at 491-1497.