For the pipe-smoking Weiss, the trials and tribulations are proving worth it. Two months ago, he and the Caltech physicists, who are now overseeing the direction of the project, received a multimilliondollar nod to forge ahead with their dream of detecting gravity waves— an unverified, extremely weak form of radiation predicted by Einstein's general theory of relativity.
Indeed, at a time when funds seem to be tightening up, the National Science Foundation renewed a commitment to the project and upped the money the plan is approved to receive—to $10.6 million over the next 30 months. And NSF officials are optimistic that the 1990 budget will allocate another $100 million to build the first full-scale gravity wave observatories.
An example of the kind of "big science" project that NSF approves only a few times each decade, the grandiose scheme calls for a huge L-shaped detector on each coast of the United States. Laser beams will race up and down the four-kilometer-long arms of each "L"—their travel times monitored by sophisticated instruments for evidence of gravity waves. Just administering the project has been difficult; conflicts between MIT and Caltech led to control being handed over to the West Coast university. And getting the apparatus to work will require pushing technology far beyond current limits.
"You're treading virgin ground wherever you go," says Rochus Vogt, the Caltech physicist who now heads the project. "Gravity is a totally new force which we have never used before."
The answer lies in the researchers' determination—and their ability to convince both peers and funding agencies that the risks are worth taking. "All the advice of all the responsible groups says this is one of the great opportunities in science," explains Richard Isaacson, NSF's program director for gravitational physics.
The greatest of these opportunities is the chance to peer almost inconceivably far back in time—to what is known as the Planck constant, a mere 10-43 seconds after the Big Bang explosion. Currently, scientists are able to "see" only as far back in time as 100,000 years after the birth of the universe. The reason: Temperatures were so great in the early universe that electrons and protons zipped around unchecked, scattering all of the electromagnetic radiation. As a result, any light from those first 100,000 years that reaches Earth today is so scrambled that its information is unreadable. Only when things finally cooled to the point that neutral atoms formed was light able to pass through unaltered to reach astronomers' telescopes.
But gravity waves are virtually immune to the cosmic scattering that occurred in the early, superhot universe. And their ability to pass unchecked through almost anything means that even those produced in the wake of the universe's tumultuous birth can still be detected. "If you could observe gravity waves, you might be able to look back all the way to the beginning of the universe, to the very first instant," says Weiss, his voice mounting with excitement. Gazing back to the moment of creation is the ultimate goal, he says, because "you want to find God."
For the slightly less ambitious, gravity waves may hold clues to a host of exotic astronomical bodies. General relativity predicts, for example, that gravitational radiation is emitted by orbiting binary stars, supernovae, and even star-gobbling black holes—all of which scientists would dearly love to study further. In fact, the mathematics of gravity waves given off from black holes have already been calculated—and detecting the waves will tell physicists if their theories are correct. "Gravity waves will give us unequivocal proof that black holes exist," says Isaacson. "That's the only way we could possibly get that information."
If gravity wave observatories open a new window on the universe, much of the credit will go to Rainer Weiss. The slim physicist has been dreaming and plotting about gravity waves ever since 1972, when, as a thought exercise, he asked his students in a graduate course on general relativity to find the simplest way to detect the phenomenon. At the time, gravity waves were an intriguing prediction of general relativity—but many physicists weren't convinced they even existed.
As the students brought the problem home to ponder, Weiss himself began to see a solution. His idea took advantage of the fact that the force of gravity waves should cause minute physical displacements in matter. To measure these movements, the physicist envisioned two detectors, placed at different ends of the country. Each site would consist of a pair of perpendicularly arranged stainless steel vacuum tubes 48 inches in diameter and four kilometers long.
In Weiss's plan, synchronized laser beams speed through the tubes and are reflected by mirrors at each end. As an incoming gravity wave passes through a detector, it pushes and pulls the mirrors like an extraordinarily weak tidal force. As a result, the light in one tunnel takes slightly longer than normal to return to its starting point; in the other tube, the light returns faster 'than usual. And when such an event occurs, scientists can begin a series of calculations enabling them to learn about the source of the gravity waves-be it a supernova explosion or a black hole. The reason for having two detectors is to provide independent confirmation of what would be extremely rare and weak events.
Other endeavors were begging for his attention, chief among them studies of the cosmic background radiation. And it wasn't until 1979, when he was freer and a series of events brought NSF into the act, that the project gained momentum. The federal science agency had long been interested in gravity waves and had given funds to several groups working on a different type of detector. But Weiss' concept promised much greater sensitivity—and NSF was interested.
At almost the same time, Weiss' plan was challenged by a rival to the west. While Weiss remained a lone advocate of gravity wave detection on the MIT campus, scientists and officials at Caltech were preparing an all-out assault on this uncharted area of astronomy.
Leading the movement was physicist Kip Thorne. Arguing that gravitational astronomy would emerge as a vital area of astrophysics, Thorne pushed for Caltech to get in early. And to start off on the right foot, Caltech reached out to Glasgow University and plucked away Ronald Drever, one of the world's premier authorities on gravity waves. Part of the lure: a new, $500,000 research facility, where Caltech has since assembled the world's largest prototype detector, with arms 40 meters long.
NSF was convinced enough to indicate more money would be forthcoming. But reluctant to fund two competing projects, the agency began to pressure for some sort of unification. At NSF's urging, MIT and Caltech entered into negotiations and the following year signed a memorandum of understanding. Rochus Vogt, who was then chairman of the division of physics, mathematics, and astronomy at Caltech, quips, "NSF married MIT and Caltech with a shotgun."
The wedding contract, in essence, called for MIT to hand over the leading role in the project to Caltech. "They were very eager to do it," explains MIT provost John Deutch, then MIT's dean of science. "I just concluded the project was going to get done as well as it could be done at Caltech."
Some scientists and officials close to the decision saw a different motive, however: that MIT didn't want to head a high-visibility, "big science" project that could turn out to be an albatross. Weiss himself considers the decision a momentous mistake, although he retained some control as a member—with Drever and Thorne—of the three man steering committee that oversaw operations. Still, such mergers are common in physics; universities learned long ago that to get funding for large-scale projects like particle accelerators it was necessary to work together.
But this time, it didn't work. Disputes between Caltech and MIT scientists threatened to fatally disrupt the project. Chief among them was the type of interferometer to develop. Caltech favored a Fabry-Perot system, where laser beams bounce back and forth between fixed spots on mirrors.
Weiss, in contrast, wanted a Michelson interferometer, in which the light travels between varying spots. The differences may seem trivial, but they weren't: The Fabry-Perot mirrors would be smaller and easier to make, while the Michelson interferometer would require less precise lasers—and neither side wanted to give up all the development work already invested in each type. "This management scheme was a bizarre thing that was cooked up and worked fine for a few years," says Isaacson. "But you don't build a $100 million construction project based on a steering committee."
In this marriage, someone clearly had to take charge. But who?
Enter Richard Garwin. An IBM Fellow and hard-headed realist widely known for his withering attacks on Reagan's Star Wars plan, Garwin had already immersed himself in the gravity wave arena by proving that an earlier method of detection didn't work. And he was skeptical of the science behind the project. "I wanted people to understand that it would be a long time before they could detect anything with the available technology," he recalls. "And when people wanted to spend $50 million or something like that on a laser interferometry gravity wave observatory, it seemed to me it really needed a summer study."
Garwin got his way. In fall 1986, a group of scientists outside the gravity wave specialty but with experience in big projects gathered at the American Academy of Arts and Sciences in Boston to consider the fate of the gravity wave detector.
The group, which included Princeton University nobelist Val Fitch and Andrew Sessler from Lawrence Berkeley Laboratory, tackled three major issues. The first two centered on the science and the technology. Was there really anything out there to detect? And could it actually be detected?
Mounting circumstantial evidence had already convinced specialists that the phenomenon did, in fact, exist. And this data, coupled with results from ongoing laboratory demonstrations at MIT and Caltech that pushed the bounds of detection sensitivity, convinced the bulk of the full committee that detection was possible. But the management issue was another story. Before recommending further funding, the committee wanted a qualified administration in place.
Caltech immediately formed a search committee to find the right administrator. Their choice was the German-born Vogt, who was then provost of Caltech. A top scientist who knew the field, he had served in a variety of technical and administrative capacities, including acting director of the Owens Valley Radio Observatory, another interferometry project.
Vogt quickly accepted. "I cannot imagine anything more important than to bring this project to a successful conclusion and establish gravity wave astronomy as a scientific discipline," he explains. "With a new force you open a new window into the universe."
The plan is now officially known as the Caltech/MIT LIGO (Laser Interferometer Gravitational Wave Observatory) project. Both institutions have teams of about a dozen persons working on the scientific questions, and Caltech also has an engineering arm with another dozen or so workers. But all decisions are in the hands of Vogt, who immediately made that clear when he took over last summer. He chose the Fabry-Perot system favored by Caltech and established himself as the project's only official voice. Weiss, for example, says he can discuss the science and history of the project, but not its administration or any internal disputes.
In order to prevail against the multitude of worthwhile ideas vying for funding, Vogt must solve a variety of administrative and political problems—in addition to hurdling the technological barriers involved in building detectors vastly more sensitive than anything yet in existence.
His goal is to construct two observatories—one at Edwards Air Force Base in the Mojave desert, the other at an undetermined eastern site. The pair would be able to identify waves and begin to probe their origin and characteristics. But to pinpoint black holes and other sources of gravitational radiation, LIGO backers are counting on efforts to construct similar detectors in Europe and Japan. So one of Vogt's major chores will be to align researchers from at least six countries now working on gravity wave detection into a more coordinated effort.
But perhaps the greatest challenge will be to ease the competition between the two U.S. institutions involved. Vogt took a step toward that end by choosing a single technological approach—but he points out that a strong history of rivalry between the two groups remains. "We cannot afford to allow silly competitions and duplications," Vogt asserts. "That's not an easy task, to shape these two teams that used to compete into one single unit. But if we fail, the project will be dead for a generation."
For his part, Rainer Weiss is acutely aware that the venture is larger than any of its scientists' egos. He would clearly like a bigger role in the project, but accepts the way the chips have fallen. "I want this real bad," Weiss confesses, rubbing a hand through his salt-and-pepper hair. "I'll do anything to make it work."
A bevy of tasks has been divided between the two groups. So, for example, while the Caltech team works with the greater detection sensitivity of its longer, 40-meter prototype, Weiss' group dutifully uses the wider tubes of its five-meter experimental detector to test larger, more complex equipment.
Even in his new, reduced role, Weiss is eagerly awaiting the first results from the project. "When you open a field up because you have a new instrument, you're bound to discover something you've never even thought about," he notes. "And I think that's the joy of the damn thing." Not to mention a chance to see God.