News this Week

Science  05 Jan 2001:
Vol. 291, Issue 5501, pp. 22
  1. PLANETARY SCIENCE

    Jupiter's Two-Faced Moon, Ganymede, Falling Into Line

    1. Richard A. Kerr

    SAN FRANCISCOAn ocean within Jupiter's giant moon Ganymede was all the news here last month, but planetary scientists were more intrigued by what they were learning about how the moon acquired its odd visage: half bright and new and half dark, heavily cratered, and ancient.

    At the fall meeting of the American Geophysical Union, researchers studying data returned by the Galileo spacecraft—which has been orbiting Jupiter since 1995— reported that Ganymede, like its neighbors Callisto and Europa, probably has a salty ocean. Ganymede's is far below its icy surface and far less promising of life than Europa's, however. As for Ganymede's split personality, researchers now believe that the more youthful-looking half could be due to a crust that stretched—as has happened in the past few million years on Europa—rather than any sort of icy volcanism, as many had assumed. All in all, Jupiter's set of four satellites “really is, as Galileo proclaimed back in 1610, another planetary system” all its own, says planetary physicist David Stevenson of the California Institute of Technology in Pasadena.

    Siblings.

    Io, Europa, Ganymede, and Callisto (l. to r.). All but Callisto have young, bright terrain.

    CREDIT: JPL/NASA

    Signs of an ocean showed up in magnetic field measurements made by the magnetometer aboard Galileo during the closest Ganymede flyby ever, on 20 May of last year. Space physicist Margaret Kivelson of the University of California, Los Angeles, and her team members reported at the meeting that Ganymede shows the same subtle signs of a buried ocean as do Europa and Callisto. As Jupiter rotates, it sweeps its mighty magnetic field through the salty subsurface waters of those satellites, inducing magnetic fields that stretch outward from the oceans. And when the great planet wobbles on its rotation axis, sometimes it immerses a moon in a magnetic field of the opposite sign, causing the moon's induced field to flip. Kivelson reported that Galileo saw such a flipped induced field on its May pass of Ganymede. That's “very strong evidence of a layer of melted water beneath Ganymede's icy surface,” she said.

    But the ocean is a distant one. To judge by the shape of its induced field, it most likely lies 170 kilometers down, compared with perhaps 10 or 20 kilometers on Europa. And, like Callisto's, it's layered between ice above and below. Europa's is underlain by rock that might have the volcanic activity needed to energize life.

    Familial resemblance.

    This 26-kilometer-wide striated lane on Ganymede formed by crustal spreading, as happens on Europa.

    CREDIT: JPL/NASA

    The Ganymede ocean may be deep-seated today, but it was not always so. Planetary geologist James Head of Brown University in Providence reported that Galileo's best look yet at Ganymede's surface shows “similarities to Europa we did not suspect before.” In the bright, young-looking areas where fuzzier images suggested smooth surfaces, he and his fellow camera team members expected to see lavalike water and ice flows from “ice volcanoes” instead, they could see rugged terrain marked by grooves formed by pervasive fracturing. At the boundary between dark and bright areas, they found deep depressions with no sign that icy lavas ever filled them. And in bright lanes where they expected signs that the crust had collapsed and water had flooded the surface, they saw that the crust had stretched and spread, as happens at mid-ocean ridges on Earth and on Europa. “This new data indicates tectonic activity seems to dominate the surface of Ganymede as it does on Europa more than the icy volcanism we expected,” said Head. An ocean near the surface, more like Europa's today, helped shape the surface of Ganymede some time in the past, he implied.

    Another Galileo instrument, the Near Infrared Mapping Spectrometer (NIMS), also saw signs of an ancient ocean on or near the surface. Planetary scientist Thomas McCord reported that NIMS detected signs of hydrated ocean salts—most likely magnesium sulfate—on the ancient dark areas of Ganymede's visage.

    Today's deep-seated ocean, crustal stretching, and surface salts all fit into a history of Ganymede that has been emerging from Galileo observations, said Stevenson. The salts seem to have been left from the moon's formative years, when the warm and watery newborn froze from the outside in as its inner heat seeped away. Callisto went through a similar slow freeze without ever altering any of its primordial crust; half of Ganymede remained unaltered as well.

    But sometime since, perhaps about a billion years ago, Ganymede seems to have gotten a shot of heat that reignited its core magnetic dynamo and expanded its nascent ocean toward the surface, says Stevenson. This rejuvenation could have happened if Ganymede temporarily stepped into the orbital “dance of the satellites” that fueled the recent resurfacing of Europa, he adds.

    As Ganymede drifted away from Jupiter, it may have passed through an orbital arrangement with other Galilean satellites that distorted its orbit into an ellipse. The resulting tidal flexing of its rock and ice—enhanced by even a thin ocean—would have temporarily heated its interior, expanded the ocean, and flexed a weakened crust. That flexing and the warmth of the ocean could have renewed and brightened the surface, or, as luck would have it, only half of it. Once beyond the resonance, Ganymede would have cooled again, stuck in its two-faced look.

  2. EMBRYO RESEARCH

    British Parliament Approves New Rules

    1. Gretchen Vogel*
    1. With reporting by Ohad Parnes in Berlin.

    The British House of Commons has overwhelmingly approved new rules governing research on embryos in the United Kingdom. If the regulation passes the House of Lords, it would allow British scientists to derive and use stem cells from human embryos and to conduct nuclear transfer experiments—the same technology that produced Dolly the sheep—with human cells.

    Opponents in Britain and elsewhere in Europe have called the 19 December vote a step down a slippery slope toward human cloning. But supporters deny that, claiming that the new rules ensure strict ethical oversight of this research, which could eventually help treat or even cure such devastating diseases as Parkinson's or diabetes.

    The measure passed by 366 to 174 in a “free” vote, in which members were allowed to vote their consciences rather than adhere to a party line. “We had no idea” how the vote would fall, says Robin Lovell-Badge, a developmental geneticist at the National Institute for Medical Research in London who works with mouse embryonic stem cells. “We were very surprised at how strong the support was.” The House of Lords is expected to vote on the measure in mid-January.

    Current British law, passed in 1990, allows researchers in the United Kingdom to conduct experiments with embryos up to 14 days old, but only for research into infertility, the causes of miscarriage, genetic or congenital diseases, or new methods of contraception. The new regulation would permit research aimed at developing treatments for disease as well.

    All such work will be regulated by the Human Fertilisation and Embryology Authority (HFEA), which oversees fertility treatments and also reviews research proposals for scientific and ethical merit before issuing licenses to work with human embryos. Unlike in the United States, where embryo research conducted by private companies is not regulated by the federal government, British researchers who attempt to do embryo research without a license would face criminal penalties, including prison.

    The HFEA has already granted several licenses for the derivation of stem cells from embryos, says developmental biologist Anne McLaren of the Wellcome/CRC Institute in Cambridge, U.K. The scientists granted these licenses specified that the cells would be used to study blastocyst quality to better understand infertility.

    Some opponents of the new regulation wanted a ban on research involving nuclear transfer techniques in human cells. Such work would attempt to create human embryonic cells with the same nuclear DNA as a patient. Those cells could then be used to derive genetically matched stem cells that might be coaxed to produce specific types of cells for treating disease. Last year, a U.K. government panel said that nuclear transfer experiments could be ethically justified if they were used to produce cells for disease treatment (Science, 25 August 2000, p. 1269), but opponents have argued that the work could lead to human cloning. “I fear that if we proceed as we are doing, we will open the floodgates,” said Edward Leigh (C-Gainsborough) during the parliamentary debate.

    German leaders have also expressed dismay about the vote. Minister for research Edelgard Bulmahn told the newspaper Frankfurter Allegemeine Zeitung that allowing nuclear transfer experiments in human cells was “breaking an ethical border.” German research should focus on exploring alternatives to the cloning of human embryos, Bulmahn said, such as stem cells derived from adult tissues. Health Minister Andrea Fischer agreed. Chancellor Gerhard Schroeder also expressed reservations. He wrote in a statement that Germany “should not yield to calls to relax the ban on the use of embryo stem cells until the potential of adult stem cells in medicine has been properly investigated.”

  3. GERMANY

    Chipping Away at Feudal Vestiges in Academe

    1. Ohad Parnes*
    1. With additional reporting by Janina Wellman. Parnes and Wellman are writers in Berlin.

    BERLINAny young German scientist hoping to carve out an academic career faces a daunting barrier: the notorious post-Ph.D. Habilitation requirement. To be eligible for tenure, young scholars are required to work for 6 years or more as a kind of academic apprentice, dependent on a senior professor for support. Now, this centuries-old academic peculiarity may finally be on the way out.

    Last week, the DFG, Germany's central research foundation, announced a new program of “junior professorships” that will provide independent support for young researchers. Beginning in the next few months, young scientists will be able to apply for 3-year support for their own research or group projects they head. At the same time, the German Donor's Association—the country's major private science-funding body— announced that it is starting a program of “research professorships.” These will fund university positions for researchers under age 35, with 150,000 DM (about $72,000) annually for a period of 4 years, for independent studies. Priority will be given to new and interdisciplinary areas of research.

    Both these new programs present a direct challenge to the hegemony of senior professors, and they are being viewed as key steps in the eventual elimination of the Habilitation requirement. A blue-ribbon committee of scientists and government officials advocated such a move last spring, arguing that Germany's academic research system should move toward the U.S. model, with “junior professor” slots replacing the Habilitation positions (Science, 21 April 2000, p. 413).

    The Habilitation system is widely seen as a disincentive for young scientists, especially women, to remain in academic research. “There is every reason to get rid of the Habilitation, and to create a new position for young scholars and scientists that gives them more autonomy,” says Lorraine Daston, an American historian who directs the Max Planck Institute for the History of Science in Berlin. The best young scholars are moving to academic positions abroad, where they do not suffer “the indignity of a system they consider feudal,” as Daston puts it.

    The German federal government backs the new initiatives. Edelgard Bulmahn, minister for education and research, has put reform of the state-governed higher education system at the top of her agenda. “It is urgently necessary that the laws which regulate the employment of professors, which were passed in the 19th century, be adapted to the new reality,” she said in a statement last fall.

    But these new initiatives are just the first step, and even they are controversial. A coalition of university professors has opposed doing away with the Habilitation because it could erode the quality of academic training. Others have argued that simply renaming the postdoctoral track from “Habilitation” to “junior professorship” will do little to alter dependency relations within the universities.

    Gerhard Sagerer, a computer scientist and dean of the technical faculty of the University of Bielefeld, argues that the system is already changing fast. He says the Habilitation has lost its importance in some fields of science and that there will be fewer fixed professorships in the future. Instead, department heads will have much more freedom to allocate resources.

    Marc Schalenberg, a young historian who has just started his Habilitation at Humboldt University in Berlin, hopes to be one of the first to profit from the new initiatives. Instead of “hanging completely in the air after my Habilitation,” he says, “I could now try and apply for a junior professorship,” which could put him on the road to a permanent academic position more quickly. But this revolution may come too late for those who are already at a relatively advanced stage of their Habilitation: Today, the average German academic is 44 by the time he or she is eligible for a tenured position.

  4. MALARIA

    Old Movie Spawns a New Discovery

    1. Martin Enserink

    Tired of Hollywood's bland holiday fare? Check out a movie showing this week on Science's Web site—a mystery thriller with a cast of two.* True, it's not a first-run film: The 87-second clip, featuring a human liver cell and a malaria parasite, was shot at a New York University (NYU) lab more than 10 years ago. But a series of recent experiments by NYU researchers, reported on page 141 of this issue, reveals a whole new story behind the video fragment.

    The movie catches a so-called sporozoite (a stage in the life cycle of the malaria-causing Plasmodium parasite) entering a human liver cell, apparently jostling its way right through, then exiting at the cell's other end and moving away as if nothing had happened. That's strange behavior for a sporozoite. Most researchers thought that after being delivered via a mosquito bite, these needlelike cells quickly traveled to the liver to infect a single cell. Inside that host cell, the sporozoite produces tens of thousands of so-called merozoites, each of which can then go on to infect red blood cells. The fact that sporozoites may travel through as many as four other liver cells before settling down in one, as the new study suggests, comes as a surprise. “This parasite is not obeying the textbooks,” says Rudolph Entzeroth, a parasitologist at the University of Technology in Dresden, Germany.

    The textbooks also assume that, as they enter a cell, Plasmodium sporozoites induce the cell's plasma membrane to encapsulate the parasite inside a vacuole—a trick employed by most parasites. But, as the movie shows, when the parasite enters and exits liver cells during its quick passage through them, it rudely punches small holes in the cell membrane, like a well-working Votomatic machine piercing an election ballot.

    NYU researcher Jerome Vanderberg, who shot the movie in 1989, was convinced all along that sporozoites didn't always follow parasitological doctrine when they invaded. Ten years ago, he published a paper showing that sporozoites could travel through a type of immune cell called a macrophage. He and several others also produced electron microscopy images showing malaria parasites inside host cells but without the typical vacuole surrounding them. But most researchers didn't know what to make of those findings, and some thought the behavior displayed in the short movie might be an artifact: The parasite might be swimming underneath the human cell, rather than passing through it. So the clip was never published, and Vanderberg's research eventually took another direction.

    But when cell biologist Ana Rodríguez came to the department last year, she took a closer look at the old footage. “I really felt that it was not an artifact,” she says. Together with her colleague Maria Mota, Rodríguez designed a series of experiments to find out what was happening. For instance, they used a test that can detect when cell membranes are wounded and repaired. When mosquito saliva containing Plasmodium yoelii sporozoites was added to cultured mouse liver cells, they found that 10% to 30% of the cells showed signs of wounding; these were wounds that would not be expected with an ordinary infection. This didn't happen when they added saliva from uninfected mosquitoes to the cells. The sporozoites also caused the liver cells to spill some of their contents—another sign that their membranes were punched.

    The team went on to show that the parasites causing this damage didn't form a vacuole inside the cell and that their passage didn't result in an infection. Rather, their repeated stealthy invasions, followed by a rapid exit, seemed to mark a prelude to the final, classical invasion, with the formation of a vacuole. The team also found that liver cells in mice infected with malaria also showed signs of wounding, reassuring researchers that this wasn't just happening in the test tube. “All in all, I think it's a very elegant demonstration of a new phase in the parasite's life cycle,” says Stephen Hoffman, a malaria researcher at the Naval Medical Research Center in Silver Spring, Maryland.

    But does that phase serve a purpose? Rodríguez can only speculate. Perhaps the parasites like to shop around to find a “good” liver cell to infect, she says. Or maybe passing through multiple liver cells somehow activates the parasite, preparing it for the real thing. Rodríguez's first priority now is to find out why parasites show this behavior and how they do it. Watch for the sequel.

  5. CANCER RESEARCH

    Preventing Hair Loss From Chemotherapy

    1. Jean Marx

    The images are painful: a cancer patient, perhaps a child without hair, or a woman wearing a scarf or all-too-obvious wig to disguise the hair loss caused by chemotherapy. Although this loss may seem trivial—it's likely to be temporary and the chemotherapy may well save the patient's life—it's not. “After nausea and vomiting, one of the harder side effects of chemotherapy is loss of image,” says cancer researcher Stephen Friend of Rosetta Inpharmatics in Kirkland, Washington. “Keeping that image intact,” he adds, “has a lot to do with fighting the disease.” Now, researchers may be on the way to developing a drug that can prevent chemotherapy-induced hair loss.

    Hair preserver.

    The CDK2 inhibitor, when rubbed on the heads of mice (bottom), prevented the hair loss caused by etoposide.

    CREDIT: S. DAVIS ET AL.

    Many chemotherapeutic agents cause hair loss because they are aimed at rapidly dividing cells—one of the defining characteristics of cancer cells. The problem is that these drugs also kill normal dividing cells, including those of the hair follicle. On page 134, Stephen Davis and his colleagues at Glaxo Wellcome Research and Development in Research Triangle Park, North Carolina, report that they can prevent chemotherapy-induced hair loss in rats by rubbing the animals' skin with a newly developed drug before administering the chemotherapy.

    The new drug targets an enzyme called cyclin-dependent kinase 2 (CDK2), which drives a key step in the cell division cycle. Many researchers in both industry and academe are looking for CDK inhibitors, mainly in hope of developing agents to block the growth of cancer cells. But William Kaelin of the Dana-Farber Cancer Institute in Boston, who is among those doing this work, points out that CDK inhibitors offer two possibilities. They can be used, he says, to find “either smarter ways to kill cancer cells or smarter ways to protect normal cells.”

    In the current work, the Glaxo Wellcome group focused on the latter goal. They began by determining the x-ray crystallographic structure of CDK2 bound to a previously identified, but relatively weak, inhibitor of the enzyme. They then used this structural information to design a modified form of the inhibitor that would bind more tightly to the enzyme, making it a more effective inhibitor, and that would also be suitable for topical application. Tests with cultured cells showed that their design strategy worked: The modified inhibitor blocked the division of the cells at just the point where CDK2 comes into play. What's more, Davis says, it “protected the cells from a panel of currently used chemotherapeutic agents.”

    The team went on to test the prospective drug in two animal models. In one, the researchers transplanted human scalp hair onto immunodeficient mice that can't reject the foreign tissue. When they applied the CDK2 inhibitor to the actively growing hair transplants, Davis says, it reversibly inhibited hair follicle cell division.

    In the second model, the researchers treated newborn rats with the CDK2 inhibitor, followed by either the chemotherapeutic drug etoposide or a cyclophosphamide- doxorubicin combination. Control animals subjected to the chemotherapies without the CDK2 inhibitor lost all their hair. But when applied to the heads of the rats before they were given etoposide, the inhibitor completely prevented hair loss at the application site in 50% of the animals and partially prevented it in another 20%. It was less effective against the drug combination, protecting 33% of the animals from hair loss. But the researchers were thrilled to see the hair still growing on many treated animals. “There's nothing better than visual proof,” Davis says.

    Because the CDK2 blocker inhibits cell growth, the team checked to see whether it interferes with the ability of the chemotherapeutic drugs to kill cancer cells in animal tumor models. Davis says that they didn't detect any such interference, and the fact that the drug is applied externally should also limit any potential interference with chemotherapy.

    Oncologist David Fisher, also at Dana-Farber, describes the work so far as an “enormous advance.” He speculates that it might also be possible to design inhibitors to protect other normal tissues that are damaged by chemotherapeutic drugs. The lining of the gut—where damage causes nausea and vomiting—is one possibility, if a nonabsorbable version can be produced.

    Davis says he doesn't know how long it might take to bring the current CDK2 inhibitor to market, as the drug is just beginning preclinical testing. But if it does eventually move into human trials, Fisher predicts, “the clinical community will pound on the door to test it.”

  6. EVOLUTION

    Tooth Theory Revises History of Mammals

    1. Erik Stokstad

    To paleontologists who study mammals, you are what you eat with. Teeth are often the only remains of tiny, extinct mammals, but they can reveal an animal's diet as well as its place on the family tree. The most important advance in mammalian dental evolution has long been regarded as the tribosphenic molar—a Cuisinart-like tooth that could both slice and grind. This was considered a key innovation, shared exclusively by placental mammals and marsupials, that helps explain their extraordinary success ever since the Cretaceous period.

    Now three paleontologists propose that the tribosphenic molar evolved not once, but twice—a highly provocative idea. “It shakes a bedrock principle that we've held for a long time,” says Andy Wyss of the University of California (UC), Santa Barbara. In the 4 January issue of Nature, the trio argues that this kind of molar independently appeared in the Southern Hemisphere in fossil relatives of the monotremes, an extremely ancient group of mammals that includes the platypus. Because the hypothesis is based on extremely limited evidence, many paleontologists are reacting cautiously. “I think many people would tend to take it with a grain of salt right now,” says Michael Woodburne of UC Riverside. But Bill Clemens of UC Berkeley adds, “It's going to be very, very stimulating.”

    Coinci-dental?

    “Unique” mammalian molars actually may have evolved twice.

    ILLUSTRATION: ADAPTED FROM Z. LUO ET AL.

    Mammal teeth have come a long way in the past 220 million years. The earliest relatives of placental and marsupial mammals had molars that sliced like pinking shears—good for chopping up insects but not for crushing tougher food. The tribosphenic molar, however, also incorporates a grinder: a cusp (called the protocone) on the upper tooth that fits like a pestle into the mortarlike basin (known as the talonid) of the lower tooth. This action allows tribosphenic mammals to crush seeds, pulp fruit, and grind up leaves.

    For most of this century, all known Mesozoic fossils of placental and marsupial mammals had tribosphenic teeth. The fossils came from Asia, Europe, and North America and showed a clear step-by-step progression toward more and more tribosphenic features. Paleontologists concluded that mammals with this type of tooth most likely had arisen from a common ancestor that lived in the Northern Hemisphere during the Early Cretaceous. Meanwhile, they thought, the more primitive, nontribosphenic monotremes had evolved in the southern continents.

    Cracks in the theory appeared in 1985, with a report of the jaw of a fossil mammal, called Steropodon, from Early Cretaceous rocks in Australia. The jaw clearly belonged to a monotreme, but it bore relatively advanced teeth that vaguely resembled tribosphenic molars. “This came as a tremendous surprise,” says Richard Cifelli of the Oklahoma Museum of Natural History in Norman. Even bigger surprises were to come. In the late 1990s, unquestionably tribosphenic molars belonging to animals called Ausktribosphenos and Ambondro turned up in Australia and Madagascar, respectively. What's more, Ambondro was found in mid-Jurassic rock—evidence that the tribosphenic molar had originated not only in the “wrong” hemisphere, but at least tens of millions of years earlier than transitional molar forms in the north. By this time, Cifelli says, “the contradiction had become absolutely impossible to ignore.”

    Trying to resolve the puzzle, Cifelli teamed up with Zhexi Luo of the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, and Zofia Kielan-Jaworowska of the Polish Academy of Sciences. The trio picked 21 living and fossil mammals, examining the widest suite of features yet. They concentrated on 55 characteristics preserved in the teeth and jaws of the three new fossils from the Southern Hemisphere.

    From similar features, the paleontologists divided the fossils into two distinct tribosphenic clans: the southern australosphenidans, which include Ausktribosphenos, Ambondro, Steropodon, and living monotremes; and the northern boreosphenidans, which include placental mammals and marsupials. The tribosphenic molar originated independently in both, they propose. By making that assumption, they say, paleontologists can continue to classify monotremes and other primitive mammals as distant cousins of marsupials and placentals, without having to assume that fully tribosphenic Jurassic mammals in the south somehow gave rise to later, less tribosphenic mammals in the north.

    Not everyone is convinced. “I think they're sticking their necks out pretty far,” Wyss says, noting that the remains of the southern fossils include only teeth and jaws—no upper teeth, skulls, or other bones. “There's a tremendous amount of missing information here.” And the existing data haven't thoroughly convinced other experts, either. “Some of the characters that Luo and company have been using to link Steropodon with Ambondro and Ausktribosphenos may be suspect,” Woodburne says.

    But, if true, the hypothesis also robs paleontologists of a long-standing touchstone. “The tribosphenic molar has been something that we have hung our hats on forever because it is so distinctive,” Cifelli says. Now, he adds, it may be time to admit that “we can have no more sacred cows”—or at least no more holy molars.

  7. BRAZIL

    Society Seeks Legislative Aide Fellow

    1. Cassio Leite Vieira*
    1. Cassio Leite Vieira is a science writer in Rio de Janeiro.

    RIO DE JANEIROBrasilia is far from the scientific centers of Brazil, but as the nation's capital it is the nerve center of government. The country's scientific establishment wants to stimulate the central synapses with a fellowship program that would begin to provide legislators and federal officials with the scientific expertise they need to carry out the nation's business.

    The new program is the brainchild of the Brazilian Society for the Advancement of Science (SBPC), a membership organization with a small staff based in São Paulo. Modeled after the long-running congressional science fellowship program run by the American Association for the Advancement of Science (which publishes Science), it's seen as a way to inject a scientific viewpoint into political debates without the taint of personal gain.

    “Yes, it's lobbying, but in the right sense,” explains Aldo Malavasi, SBPC's secretary-general, using a word that is traditionally associated here with under-the-table payoffs. “The idea is to provide legislators with information that will help them make decisions that involve aspects of science and technology,” says Malavasi, a researcher at the Institute of Biosciences at the University of São Paulo.

    The society is hoping to find a senior scientist willing to spend a year away from research, in Brasilia, responding to legislative queries and filing quarterly reports. The concept has been endorsed by the parliament's Commission on Science and Technology, says SBPC president Glaci Zancan, noting that the commission would like to have additional expertise on hand during debates over scientific and technical issues.

    The society is offering a stipend of $2000 a month and a generous travel allowance. Zancan hopes to select someone next month and have that person on the job in March, but she acknowledges that it might not be easy to find the right candidate. “We are looking for a senior researcher with a great capacity for communicating science to legislators and the public,” says Zancan, a researcher with the Department of Biochemistry and Molecular Biology at the Federal University of Paraná. “It will take a special person.”

  8. MEDICAL RESEARCH

    NIH Kills Deal to Upgrade Heart Data

    1. Andrew Lawler

    BOSTONWhat was heralded as a new model of public-private collaboration in medical research suffered a surprise reversal last week. A controversial plan to use private capital to upgrade a valuable public database collapsed amid concerns that it would cede too much control to a for-profit company. Boston University (BU), which runs the venerable Framingham Heart Study, and the National Institutes of Health (NIH), which funds the 52-year-old effort, instead will try to put together a nonprofit consortium in the coming year to modernize the massive database.

    The decision, announced in a 26 December joint letter to the study participants, deals a mortal blow to Framingham Genomic Medicine Inc. of Framingham, Massachusetts, which was raising money to organize, digitize, and analyze the Framingham data. The company planned to repackage and sell data to the pharmaceutical industry (Science, 30 June 2000, p. 2301). The NIH decision also is a disappointment to BU, which was instrumental in forming the company. But the participants knew it would be risky: “There just wasn't a precedent for doing this,” says Aram Chobanian, dean of BU's medical school.

    The study has monitored the health of more than 10,000 people in the small town of Framingham during the last half-century, and it offers a treasure trove of data for researchers. But much of it is stored in boxes or file cabinets. NIH has been reluctant to put up the millions of dollars needed to update and upgrade the database, so BU hit upon the idea of getting a private company to do it instead. Its proposal, announced to the Framingham participants in April, raised tough ethical issues, ranging from questions about how outside scientists would get access to the revamped data to whether personal medical data collected with public money should be sold to private companies.

    Ultimately, negotiations between BU and the National Heart, Lung, and Blood Institute foundered on how to balance scientific access to the data with the company's proprietary interests. “BU was under some pressure from the company to reach an agreement which gave them close to exclusive access to the data,” says Claude Lenfant, the institute director. “We could not go along with that.” He says that the institute was willing to make concessions, such as giving the company exclusive rights to data for the first 2 years, but this proved insufficient. Company officials could not be reached for comment. “The rationale was good, but the methodology was not,” says Jay Lander, a Framingham attorney and vice chair of Friends of Framingham Heart Study, which represents participants.

    Now, the challenge is to find a new way to pay for the database. Lenfant envisions a cooperative agreement among companies, nonprofits, and other interested groups. He said he intends to draft a plan this year, after BU's contract to conduct the study is renewed in the next couple of months. But he insists that the raw data should be available to everyone, and that only refined data should be private property. Chobanian agrees that that approach is now the way to go. “It's a slower and less effective way,” he adds, “but probably better in the long term.”

  9. ASTROPHYSICS

    Ravenous Black Holes Never Say Diet

    1. Mark Sincell*
    1. Mark Sincell is a science writer in Houston.

    AUSTIN, TEXASAs more and more observations confirm that supermassive black holes stud galactic centers like celestial Starbucks, astronomers are starting to puzzle out the dark giants' life cycles. Now, a pair of new methods for probing the secret hearts of galaxies, presented here at a recent meeting,* is overturning a widely held assumption that supermassive black holes stopped growing after forming in the early universe. And the new methods could soon enable astronomers to tell the entire life story of a black hole.

    For years, astronomers could estimate the mass of a black hole only by laboriously clocking the motion of individual stars in the surrounding galaxy. Six months ago, however, teams led by astronomers Karl Gebhardt of the University of Texas, Austin, and Laura Ferrarese of Rutgers University in New Brunswick, New Jersey, made a crucial discovery: The mass of the black holes, as determined from individual star motions, is exactly proportional to the overall motion of the stars in the galaxy's central bulge.

    “It is a perfect line,” Ferrarese says. For nearby galaxies, astronomers can calculate that overall motion, or velocity dispersion, by studying the Doppler shift of light from the bulge. “It just takes an hour on a ground-based 4-meter telescope,” Ferrarese says. Then the linear relationship makes it easy to weigh the black hole.

    Unfortunately, the oldest, most active supermassive black holes lurk in host galaxies too far away for astronomers to measure their velocity dispersions. So Gebhardt has calibrated a previously suggested way to calculate mass at even greater distances, by studying the light from quasars—the unimaginably powerful energy fountains that issue from many galactic black holes.

    Gebhardt starts by creating a “reverberation map” that relates the daily fluctuations in a quasar's brightness to corresponding flickers in light reflected from clouds orbiting the black hole. From the time delays between the arrival of the quasar's light and the reflected cloud light, he calculates how far the clouds are from the quasar. Combining that distance with Doppler measurements of the reflected light tells how fast the clouds are orbiting the black hole. That velocity, in turn, reveals the black hole's mass.

    When Gebhardt compared his reverberation-map estimates of black hole masses with velocity-dispersion measurements from several nearby galaxies, they agreed beautifully. “Right now, we are confident we can measure the black hole mass within a factor of 2,” Gebhardt says, “and that should soon improve to an accuracy of 30% to 40%.” Because the method works for even the most distant quasars, Gebhardt hopes to use it to map the entire growth history of supermassive black holes. “This opens a region far beyond the reach of stellar dynamics,” Ferrarese agrees.

    Not all the action is in the distant universe. As many as 10% of the black holes in neighboring galaxies are still gobbling up gas and putting on weight, a team of astronomers led by Amy Barger of the University of Hawaii, Manoa, reported here last week. To find the active black holes, Barger's team first pointed the Chandra X-ray Telescope at an empty patch of sky, where they found 20 new high-energy x-ray sources. Follow-up optical observations showed that the x-ray sources came from a larger group of hundreds of optically bright galaxies. Applying a variation of the mass-velocity dispersion relationship that says the optical luminosity of a galaxy is proportional to the black hole's mass, the Barger team concluded that the unusually bright nearby galaxies contain supermassive black holes.

    To produce so many dust-penetrating x-rays, the resident black holes must be chowing down on galactic gas, the team reports. Extrapolating from the researchers' sample, Barger concludes that as many as 10% of all supermassive black holes are still active today.

    “They have done a beautiful job,” says astrophysicist Andy Fabian of the Institute of Astronomy in Cambridge, U.K. But 20 galaxies aren't enough to convince Fabian and others that so many supermassive black holes are still active, and eating, today. Barger's team expects to glean more examples from Chandra observations scheduled this year.

    • * Texas Symposium on Relativistic Astrophysics, 10 to 15 December 2000.

  10. INDIA

    Scientist Restored to Top Agriculture Post

    1. Pallava Bagla

    NEW DELHIThe Indian government's top agricultural scientist has regained his post after being removed during an inquiry into financial irregularities at his agency (Science, 24 November 2000, p. 1477). The move is being applauded by scientists, who felt that the government's action against R. S. Paroda, director-general of the Indian Council of Agricultural Research, was unwarranted.

    Paroda was taken off the job on 16 November as part of a probe into the diversion of computers purchased on a World Bank-funded technology project. On 24 December, Agriculture Minister Nitish Kumar said that Paroda was being reinstated because he “is not related to the matters on which the inquiry was ordered.”

    Scientists had been particularly upset that the action came just before the annual Indian Science Congress, a megaevent held in early January over which Paroda is presiding. It was the first time that a secretary of any of the science departments had been removed so abruptly in a matter involving possible corruption, and also the first time the government had reversed itself so quickly.

  11. JAPAN

    Superagency Seeks to Reconcile Two Cultures

    1. Dennis Normile

    TOKYOShigeharu Kato says he can recognize the different personalities of the people who fund Japanese science by the level of noise in the hallways. At the hands-on, applied Science and Technology Agency (STA), where he works, “people are always running through the halls.” But at the ivory-towered Ministry of Education, Science, Sports, and Culture (Monbusho), where he was temporarily assigned to prepare for the pending merger of the two scientific heavyweights, “I never saw anyone running through the corridors.”

    The merger, which becomes official on 6 January, creates one superministry that will oversee 75% of public money spent on research and a similar proportion of the scientific workforce funded by the government. It's part of a long-planned consolidation of 22 cabinet-level agencies into 12, aimed at improving efficiency and reducing the overlapping responsibilities that have sparked bitter turf battles across many sectors. STA, with its 560 employees and $650 million budget, is being folded into the larger Monbusho, which has a staff of 1600 and spends $53 billion annually. Its new name reflects its basket of responsibilities: the Ministry of Education, Science, Technology, Sports, and Culture, or Monbukagakusho in Japanese.

    The two agencies currently play different roles in the nation's research efforts. STA enjoys launching strategic, big-science projects, such as commercial rocket development and nuclear power research. More recently it has ramped up research efforts in emerging fields, such as neuroscience and genomics, that offer a potentially large economic payoff. Its staffers pride themselves on their technical expertise, and a senior U.S. scientist who has been involved with numerous bilateral collaborative research efforts says that STA officials generally master the details more quickly than do their counterparts at Monbusho.

    In contrast, Monbusho is responsibile for activities ranging from kindergarten to graduate schools, and from sports to the arts. For science, it divvies up small grants to tens of thousands of university researchers and larger awards to institutes working in fundamental fields such as high-energy physics and astronomy. Its employees typically have backgrounds in the humanities.

    Scientists are eager to learn how the new agency will reconcile these two divergent approaches to funding basic science. “The cultural differences between the two agencies are immense,” says Hiroo Imura, an endocrinologist and former president of Kyoto University who is now a key government science adviser. Kato says STA officials feel a sense of urgency in bankrolling projects at the cutting edge of a globally competitive enterprise, while Monbusho tries to maintain an established, fairly successful program of academic research. Takahito Ohki, director of the Office of Administrative Reform at Monbusho, says his ministry may deserve its conservative image, but he feels caution has been warranted. “We had to take a longer, broader view of things and not just follow the latest scientific trends,” he says.

    Those differences in culture are reflected in the work layout at each agency, agrees Sanae Aoki, a Monbusho staffer assigned temporarily to STA. “In Monbusho, each division has its own room, while several of STA's divisions are all in the same room with no partitions,” says Aoki. She believes STA's open office plan enhances communication between divisions, which in turn helps them unite behind STA's major science initiatives. Monbusho's divisions, on the other hand, have orthogonal responsibilities that require them to operate more independently.

    Scientists would like to see STA's innovative new funding schemes for emerging fields united with Monbusho's unwavering across-the-board support for basic research. They appreciate the technical expertise that STA's scientists and engineers can bring to large-scale projects and international collaborations, but they also like the hands-off approach taken by Monbusho's humanities graduates toward scientific research. “My worry is that STA staff will have a stronger voice [in the new ministry's scientific affairs],” says Hiroshi Yoshikawa, a former president of the University of Tokyo who is now president of the Science Council of Japan, the nation's largest association of researchers. “That might tip the balance from basic research to more applied science.”

    “The ministry where education, science, technology, and culture are being integrated should be the leading ministry for the 21st century.” —Shigeharu Kato

    Walk, don't run.

    Small, quiet offices suit Monbusho's mission, says Sanae Aoki.

    CREDITS: D. NORMILE

    Some researchers also worry that the merger is being driven more by politics than policy considerations. “This reorganization was just about slimming the bureaucracy; there was no vision as to what it might mean for science,” says Kiyoshi Kurokawa, dean of the medical school at the private Tokai University. Officials admit that greater efficiency was the impetus for the government-wide merger. But they believe that a consolidated workforce will also raise the visibility of science and strengthen the nation's research enterprise. “The 21st century is said to be the century of knowledge,” says Kato. “So the ministry where education, science, technology, and culture are being integrated should be the leading ministry for the 21st century.”

    One important change already under way, says Motoyasu Abe, director of STA's Office of Administrative Reform, is the removal of the barriers between researchers affiliated with both agencies. Previously, university researchers had to set up off-campus laboratories for work funded by STA grants. “The walls between university-related and non-university-related institutions and researchers will be removed,” says Abe. “This should make it easier for us to do our job of promoting research.”

    Imura believes that, just as with any union, it may be several years before it's clear whether the offspring is a beauty or a beast. In the meantime, he offers the old saw about how a child produced by George Bernard Shaw and a young starlet might be either brilliant and beautiful, or dumb and ugly. “If the best of the two agencies emerges, it would be really great,” he says. “If it is the worst of the two, it would be a disaster.”

  12. POLICY

    NASA's Street Fighter Takes on Tangled Space Science Program

    1. Andrew Lawler

    At the helm of NASA's troubled space science program, Ed Weiler scrambles to carry out research in an era of soaring costs and uncertain politics

    Less than a month after taking over as acting space science chief at NASA, Ed Weiler had a tough call to make. Should he delay the $1.5 billion Chandra X-ray Telescope so that engineers in a California factory could work out the remaining bugs? Or should he ship Chandra cross-country to the Kennedy Space Center in Florida, cross his fingers, and hope for the best?

    A delay would add millions to the cost of the mission, disrupt the intricate space shuttle schedule, and anger researchers eager to do science. But as the long-time program scientist of the Hubble Space Telescope effort, whose faulty mirror had to be corrected in space, Weiler knew that haste might have even more serious consequences. His instincts told him to wait. “I overruled three independent review teams” who recommended shipment, he recalls. “It just did not feel right to me.”

    On a mission.

    As Cassini speeds toward Saturn, NASA's Ed Weiler must navigate political forces on Earth.

    CREDIT: RICK KOZAK

    Admiring Weiler's chutzpah, NASA Administrator Dan Goldin immediately made him permanent space science associate administrator, with authority over NASA's $2.4 billion program in planetary sciences, astronomy, astrophysics, and solar and terrestrial physics. And Weiler's caution has been vindicated by the near-flawless performance for Chandra, launched in July 1999.

    Weiler's job hasn't gotten any easier, however. Under his watch, two Mars probes failed in a very public and very embarrassing fashion, forcing him to completely revamp NASA's Mars management and strategy. He's also watched as the cost of virtually every major mission being developed has soared, prompting him to delay or cancel programs. Two weeks ago he bit another bullet, announcing an unprecedented open competition to find a cheaper way to go to Pluto after deciding earlier this fall to suspend a mission being planned by the Jet Propulsion Laboratory (JPL) in Pasadena, California. “He's got a lot of problems,” says John Huchra, an astronomer at the Harvard-Smithsonian Center in Cambridge, Massachusetts.

    It's small consolation that most of those problems were sown long before Weiler took over. The ambitious plans made in the mid-1990s—to explore Mars and the outer solar system, to search for extrasolar planets, and to expand dramatically the number of small missions—now seem hopelessly optimistic. And the impending Republican takeover of the White House and Goldin's likely departure only heighten the sense of uncertainty. “I'm afraid the new Administration will be a little surprised by the mess they are being handed,” says one executive branch official.

    Unlike political appointees such as Goldin, Weiler is a civil servant who can ride out changes at the White House. But that job security also means he must explain the mess to his new bosses. “Little did I know what I was getting into,” he says ruefully.

    Brass knuckles

    Weiler, 51, grew up in a working class neighborhood in Chicago, where he built a small telescope and decided by eighth grade that he would be a NASA astronomer. He worked his way through college, winning his Ph.D. in astrophysics from Northwestern University in nearby Evanston. He also got a taste of the military and the media, serving as an Army policeman while in the reserves and covering space missions as a summer intern at a public television station. He launched his scientific career as a postdoc at Princeton University under famed astronomer Lyman Spitzer, spiritual father of the Hubble, before taking over operations for a Princeton space-based telescope called Copernicus.

    His talents soon caught the attention of NASA managers at Washington headquarters. “He could handle engineering and management, was straightforward and honest, and had a good grasp of the problem of communicating science,” says former NASA astronomy chief Nancy Roman, who hired Weiler in 1978. A year later, Weiler began what turned out to be a 20-year gig as Hubble program scientist.

    His outspoken and tenacious manner may have ruffled the soft-spoken Southern engineers who dominated the culture at NASA headquarters. But Weiler earned his stripes by keeping the Hubble program alive during the dark times following its launch in 1990. One thankless job was appearing before congressional committees outraged by the spherical aberration that had blurred Hubble's vision. “We got beaten up,” he says. “We were fighting for our lives, and there were people in our own [astronomy] community saying, ‘Shut this darn thing off.’”

    He also sparred with Hubble scientists, whom he pushed hard to release data that would demonstrate the program was producing good science. That push irritated some researchers, who complained that they might be overstating the importance of the results (Science, 4 June 1993, p. 1416). But to Weiler, getting pictures out quickly was an act of political survival, as well as a responsibility of those supported with public funds. Indeed, he first visited JPL as a reporter, and he toyed with the idea of a broadcasting career during a summer media internship at a public television station in San Diego. “But the station people told me there was no money” in journalism, he says, “and that I was better off being a scientist.”

    Weiler's tenacity impressed other researchers. “He kept the community organized, kept up support, and was always on top of the scientific rationale,” says Shelby Tilford, a retired senior NASA scientist. “He was the most intense fighter for a program I ever saw.” Adds one astronomer who knows him well: “He's all brass knuckles. Ed is a street fighter.”

    Crash course

    But that single-minded focus led some scientists to worry about his suitability as head of the entire space science program. “The concern at first was that he would be too parochial,” says Claude Canizares, an astrophysicist at the Massachusetts Institute of Technology and a principal investigator for Chandra. “We all had that concern,” adds Tilford. But the events of the past few years have given Weiler a literal crash course in other fields, especially planetary science. The disastrous failures of both a Mars orbiter and lander in 1999 forced him to order a revamping of the agency's entire scientific, managerial, and technical strategy for Mars. “Mars was a nightmare,” he says. Most researchers believe that a new and far less ambitious plan, unveiled in October (Science, 3 November, p. 915) is more realistic and balanced. And while some complain it is too timid, Weiler says “I will take on anyone” who maintains the old plan was doable.

    With a new Mars strategy in place, Weiler now must grapple with the prosaic but more far-reaching effects of the failures—rising costs. He traces the problem to the heady days of 1996, when researchers claimed evidence of past life in a Mars meteorite. Vice President Al Gore convened a White House conclave to discuss the implications of life beyond Earth, and an array of new missions—such as one to Jupiter's intriguing moon Europa—was planned to search for life and its origins. The following year, JPL's Mars Pathfinder bounced to a landing and sent out a tiny rover which captured the public's imagination. “There was a cockeyed sense of optimism,” says one Mars researcher.

    Mars lander streaks toward the surface

    CREDIT: JSC/NASA

    That optimism translated into unrealistic cost estimates, however. “Basically, all the programs proposed in that era are overrun,” says Weiler. JPL, which specializes in planetary probes, was one of the worse offenders. An investigation into the Mars failures reported this spring that insufficient testing and oversight were major causes. In reaction, program managers across the agency are estimating more conservatively. But that leaves Weiler with the unpleasant task of choosing which missions should live and which should die.

    For example, this summer Weiler killed a JPL asteroid microrover mission after its estimated cost tripled. Weeks later he halted work on a flyby of Pluto (Science, 17 November, p. 1270). Weiler was concerned that NASA could not afford both the Pluto flyby and a Europa probe after the combined cost of the two missions more than doubled, to $1.5 billion.

    Last month, Weiler bowed to pressure from the science community to save the program by ordering an open competition for the mission, once assumed to be the property of JPL. Given that Europa's launch date has slipped from 2003 to the end of the decade or beyond, Weiler now says Pluto is worth saving to ensure a steady flow of outer solar system data after Cassini's 2004 visit to Saturn. “My concern is that if we just do Europa, it is going to tie up the budget so much for the next 8 years that the whole concept of an outer planets program is going to be lost.”

    A winner for a launch to Pluto between 2004 and 2006 could be named by fall 2001. But Weiler makes no guarantees about funding the initiative, recognizing that its fate hangs on the new Administration. The Clinton White House was drawn to the possibility of life below Europa's icy crust, preferring it to what one Administration official describes derisively as “a 30-minute flyby of a cold rock.” Holding a Pluto competition, Weiler argues, gives the new president and Congress greater flexibility.

    Pluto is only one of a handful of tough budget challenges facing Weiler. For example, the price of the Next Generation Space Telescope has been capped at $500 million, but many agency and industry officials expect it to cost more than $1 billion—even as its planned mirror size is shrinking. In addition, NASA's 5-year budget projections do not cover a significant portion of even the more modest Mars program. One sign of the strain is the recent suspension of funding, for at least a year, of finalists in NASA's small explorer program.

    These financial quandaries haven't stopped Weiler from touting a new series of missions, however. Two favorites are the Laser Interferometer Space Antenna, which would observe gravitational waves, and Constellation-X, which would study the formation of black holes. He would also like to bring back samples from Mars before the current 2014 date, and land a flotilla of small spacecraft outfitted with geological and astrobiology experiments, called Scouts. “I really want to blanket that planet, and land in some of the really weird places,” he adds.

    Positive vibes

    Some researchers grumble that Weiler and Goldin haven't pushed hard enough for more money to ease the crunch on current programs and to make room for new ones. NASA's space science budget has remained stagnant for a decade, despite successes such as Chandra, widespread publicity on its research findings, and a generally favorable attitude among politicians toward robotic space missions. And this is happening at a time when other science agencies are scoring double-digit increases. Weiler himself proclaims this “a mystery” and a source of great frustration.

    But few scientists are calling for his head. There's a feeling in the scientific community that Weiler is their best hope for fixing the problems and finding a way to launch more missions and carry out more science. “He may rub some people the wrong way, but he's doing an excellent job,” says David Black, director of Houston's Lunar and Planetary Institute. “He's taken a pretty strong initiative in a variety of fields,” adds Lou Lanzerotti, a physicist and engineer with Lucent Technologies in Murray Hill, New Jersey. “I get positive vibes.” Adds Huchra: “Overall, the community gives him good grades.”

    So far, Weiler's trademark bluntness is proving to be an asset. Although not physically imposing at 1.75 meters tall, “Ed can scare and alarm people,” says one scientist, particularly people at JPL. But his willingness to say what he thinks (see sidebar) and to defend his turf wins him generally high marks from Congress, the White House, and his fellow agency managers.

    That style is in stark contrast to the calm and diplomatic manner of his predecessors, including Wes Huntress, now director of the Carnegie Institution of Washington's geophysical lab. His frank approach is “refreshing,” explains one administrator. “He's a straight-shooter, and he's diplomatic enough,” adds a congressional staffer.

    Weiler doesn't much care if he's liked, and he avoids the socializing that often goes with an administrative job in Washington. He makes it clear that he is ready to use all of his street smarts on behalf of space science in the budget and political battles that lie ahead. He used to keep a copy of Machiavelli's The Prince on his desk to tease a colleague that he jokingly labels “Mr. Nice Guy.” Being nice is easy, he says, “when you don't have a budget to manage.”

  13. POLICY

    'I Don't Have the Authority to Solve Everyone's Problems'

    Ed Weiler, NASA associate administrator for space science, spoke candidly about a variety of issues facing NASA and the community during an interview last month with Science reporter Andrew Lawler.

    On the 1999 Mars failures

    “It was a disaster. And it got worse each day: This [item] wasn't budgeted, these guys weren't talking to those guys, project scientists weren't being listened to. [More] money would have made a difference, but not all the difference. There was a serious management communication problem—the fact that a low-level [employee] is afraid to go to top management, the fact that [JPL Director] Ed Stone didn't know what was going on. It was not his fault; people weren't telling him. And I understand why they didn't call [NASA] headquarters. Headquarters already had sent them all the money. So why bother?”

    On fiscal restraints

    “I had this idea that the associate administrator has hundreds of millions of dollars just waiting to solve problems. So the first thing I did was to look for where [former NASA space science chief] Wes [Huntress] had hid the money. All I found in the desk drawers were a bunch of Mars Observer buttons—no cash, no checkbook. So that was my first hard lesson: I don't have the authority or the ability to solve everyone's problems.”

    On spiraling costs

    “We had a bad habit of overconfidence in estimating costs before we started building hardware. In 1998, the budget for Europa and Pluto was [said to be] $654.0 million. There is no way in [that early stage] you can come up with a four-significant-figure budget. It befuddles me why people are surprised I took action when a [NASA] center said in June 2000, just 18 months later, ‘Oops, it's $1.486 billion.’ All I did was say we can't do both [missions]—we don't have the money.”

    On public understanding

    “I put myself through Northwestern, [working] at an open house program [at the observatory]. I started meeting the public and got lots of questions about why we should be putting money into science. Frankly, I think all graduate students should be forced to go through that process. The biggest frustration I have with U.S. scientists is that we think we deserve public funding. I wish we lived in a world like that. I agree that, in a healthy culture, science should justify itself. But we don't live in that utopia. And there's a lot of competition out there.”

    On human space flight

    “If it weren't for human space flight, Hubble would be junk! It saved the space science program. … I'm a strong supporter of the robotic exploration of Mars first, but in my heart I know we will not fully experience Mars and get all the science we can until a human can get there and lift a rock or drill down. Even more important to the human soul is seeing Mars with human eyes. That is worth something that is not part of being a scientist, but part of being human.”

    On life in the universe

    “I personally believe the universe is teeming with life. It's incredibly arrogant to say that [our solar system] is the only place in the universe where intelligent life evolved. My biggest regret is that I will not live long enough to see that first contact.”

  14. 2001 U.S. BUDGET

    Record Year for Science, But Can It Be Repeated?

    1. David Malakoff

    Science won record increases last year, but a new president, a slowing economy, and stiff competition could make an encore difficult

    Science funding advocates are still breathless from the success they enjoyed in Washington in 2000. But disinclined to rest on their laurels, they're already fretting about how to maintain the momentum in the new year.

    On 21 December, President Bill Clinton capped a banner year for science by signing the last of the 13 annual spending bills that detail the U.S. government's $1.8 trillion budget. Only one-third of that money is available for so-called discretionary spending, but legislators committed nearly 15%, or nearly $91 billion, to research and development (R&D) (see table). That record total is 9.1% higher than last year and far above the $85.4 billion requested by the Clinton Administration, according to an annual analysis prepared by the American Association for the Advancement of Science (AAAS, publisher of Science).

    Leading the way were major increases for the National Institutes of Health (NIH), the National Science Foundation (NSF), and basic science programs at the departments of Defense and Energy. The boosts push nondefense R&D to an all-time high of $45.4 billion, essentially matching the $45.5 billion slated for military-related research. More significantly, the 2001 figures end years of stagnating budgets for nonbiomedical research.

    But science lobbyists worry that repeating such gains could be difficult in the 2002 fiscal year that begins on 1 October. “A number of factors will make our lives more anxious,” predicts one lobbyist for a major research university. A slowing economy could reduce projected surpluses in the federal budget and make lawmakers wary of funneling more cash into basic research. And new leadership in the White House and several key congressional committees could also complicate the budget-making process.

    View this table:

    The annual rite will begin next month, when the outgoing Clinton team releases a “steady-state” budget that holds spending increases to a projected 3% or 4% rate of inflation. The incoming Bush Administration won't unveil its budget priorities until March or April, and even then, it will produce only an outline that could take months to fill out. As a result, “We have to be prepared for some numbers that are not going to look terribly good at the beginning,” says physicist Michael Lubell, lead lobbyist for the American Physical Society in Washington, D.C.

    Apart from pushing for a bigger budget, groups are also preparing for battles on a range of other issues, including revitalizing the Department of Energy's (DOE's) Office of Science, the government's third-largest civilian research funder.

    Last month, 11 prominent physical scientists—including former Clinton White House science adviser John Gibbons and two former DOE science chiefs, Martha Krebs of the University of California, Los Angeles, and Princeton University's William Happer—declared that DOE's $3 billion science program is in “crisis” due to strained budgets and DOE security and pollution cleanup scandals. “The problems “have given the overall agency a negative image that, in practice, has proved damaging to … its missions in science and energy,” the group concludes.

    The five-page discussion paper offers two possible solutions. One is to promote the science chief to the rank of undersecretary, improving “the visibility and influence of science at DOE.” A more radical alternative is to create a new “National Institute of Science and Advanced Technology,” similar to NASA or NIH, that would merge R&D programs at DOE and the Department of Commerce. “The new agency would be a visible recognition by the U.S. government that long-term research drives economic progress,” the panel says. With much of official Washington on holiday, there's been little reaction to the proposals so far. But Lubell says that “it's important to get them on the table so the discussion can begin.”

  15. ARCHAEOLOGY

    Japanese Fraud Highlights Media-Driven Research Ethic

    1. Dennis Normile

    Shinichi Fujimura's ability to plant stone tools to bolster the case for earlier human settlement in Japan raises troubling questions for the field

    TOKYOIt was early in the morning of 22 October when amateur archaeologist Shinichi Fujimura snuck onto the Kamitakamori excavation, dug several holes with a shovel, dropped in some stone tools believed to be 30,000 or so years old, and then covered them with earth. Five days later, he invited a crowd of journalists to this site 350 kilometers northeast of Tokyo to hear him describe an incredible find: Caches of stone tools seemingly arranged in a symbolic way in a stratum dated to nearly 600,000 years ago, signifying a much earlier dispersion and evolution of Homo erectus in northeast Asia than other evidence suggests.

    Unfortunately for Fujimura, a team of reporters from the Mainichi Shimbun, a leading national daily, had captured his escapade on video. The newspaper had been tracking him for 6 months in the wake of rumors about the veracity of earlier discoveries, and on 5 November the damning photographs appeared on its front page. Hours later, Fujimura held a press conference at which he confessed to planting artifacts at Kamitakamori and a second site in Hokkaido, the country's northernmost island.

    Fujimura's confession dealt a body blow to claims of a much older human settlement in Japan and casts doubt on dozens, if not hundreds, of related findings. But it also cuts close to the bone of the country's scientific enterprise. It exposes a sloppy side of Japanese archaeology in which press conferences take precedence over publication, few scientists bother to study artifacts once they are plucked from the ground, and there is little public debate over the scientific merits of any claim. The result, says Toshiki Takeoka, an archaeologist at Kyoritsu Women's University in Tokyo, is that Japanese archaeology “isn't really about scholarship, it's about making spectacular discoveries.”

    Fujimura's headline-grabbing discoveries played neatly into a scientific mystery. It begins with the generally accepted view that early humans lived in northern China about 600,000 years ago. During that era, Japan was periodically connected to the continent by land bridges that emerged as sea levels dropped. There's evidence that land mammals crossed these bridges and spread through the Japanese archipelago, but no conclusive sign of early humans doing the same. Instead, firm evidence of humans in Japan goes back only 30,000 to 35,000 years.

    Armed with only a high school education, Fujimura turned a passion for archaeology into a series of remarkable discoveries of stone artifacts that steadily pushed back those dates. He was said to have “god's hand” because of his knack for finding materials that had eluded others. In 1992, he and two trained archaeologists set up the Tohoku Paleolithic Institute in Tagajo, near Sendai, 300 kilometers northeast of Tokyo, to hunt for Paleolithic sites.

    Fujimura said at his November press conference that he was under great pressure to come up with discoveries. Scientists say this competition has had a corroding effect on archaeology in Japan. Press conferences are typically held at sites to trumpet the latest findings. The findings are quickly circulated among both the public and the profession with little critical review or scholarly debate, says Charles Keally, an American archaeologist who has lived and worked in Japan for 30 years.

    In the aftermath of the Mainichi expose, dozens of scientists have written newspaper editorials or spoken on TV talk shows about their persistent doubts about Fujimura's work. But Keally and others say it is an indictment of the field that these doubters didn't surface until the newspaper had done the detective work for them. “Few critics of the Kamitakamori finds have taken the time to actually go and examine the artifacts,” adds Keally, who says he must shoulder some of the blame.

    Takeoka is one scientist who did take this task seriously, and his experience is sobering. After concluding that one batch of artifacts belonged to the Jomon era, roughly 4000 to 14,000 years ago, Takeoka submitted a paper to the Japanese journal Paleolithic Archaeology. But he says the editors cut out the most critical sections. Kazuto Matsufuji, an assistant professor of archaeology at Doshisha University in Kyoto who reviewed Takeoka's paper, says that Takeoka was asked to change sections alluding to rumors of planted artifacts because “the editorial committee decided we could not, as a scientific journal, publish rumors in a research paper.” Takeoka says that even a toned-down version raised the hackles of colleagues.

    Keiichi Omoto, an anthropologist and director of the International Research Center for Japanese Studies in Kyoto, says that one reason the Kamitakamori findings were accepted so uncritically was that they fit the expectations of leading scientists, in particular Chosuke Serizawa, a professor emeritus of Tohoku University. The findings would have bolstered Serizawa's controversial claim that stone tools he unearthed in the 1960s and ‘70s date back 300,000 years. Omoto says that Serizawa's stature and his role as mentor to Hiroshi Kajiwara, an archaeologist at Tohoku Fukushi University and deputy director of the Tohoku institute, tended to deflect criticism of the Tohoku group's findings.

    Serizawa says that he made no attempt to shield the group from criticism. In fact, he says he also had questions about the dating of the artifacts, which he recently published in Chuo Koron, a leading intellectual magazine. But he didn't express his reservations earlier, either to the group or in public, because “they said there was no mistaking the old strata that yielded the artifacts.”

    Fujimura emerged from seclusion on 18 December to reiterate his claim that he had planted findings at only the Kamitakamori and Hokkaido sites. But Kajiwara agrees that a large cloud now hangs over all of Fujimura's work, which involves 33 excavations directly and extends to 160 other efforts. Nevertheless, Kajiwara says, “I still have confidence that we are working with Paleolithic sites.” Peter Bleed, a professor of anthropology at the University of Nebraska, Lincoln, who just completed a 6-month stint as a guest professor at Tohoku University Museum, agrees. “It would be a real tragedy if researchers elsewhere concluded that none of the early Paleolithic evidence coming out of Japan could be trusted,” he says.

    There is also no consensus on how to correct the deeper problems that may have contributed to the fraud. Serizawa blames it on Fujimura's popularity with the media and a lack of analysis. “From the 1950s through the 1970s, we never had these problems, and I have confidence in the work done in those years,” he says. “The problems started in the 1980s, and they can be resolved by investigating the artifacts Fujimura was involved with,” he adds. Kajiwara predicts that “there will be a change in how these press conferences are arranged.”

    But many think the problem runs deeper. Ken Amakasu, professor emeritus of Niigata University and chairman of the Japanese Archaeological Association, says, “It is clear that more time should be spent on analysis before making claims.” Greater collaboration with foreign scientists would raise standards of scholarship and introduce the notion of free-wheeling scientific debate, Omoto believes, although Keally warns that their impact would be lessened by language and cultural barriers.

    Takeoka isn't sure what will happen, but he's hopeful that his colleagues will learn from Fujimura's misconduct. “I do think researchers are reflecting on various aspects of this incident,” he says. “If this leads to even a little improvement in the current state of affairs, I'll be really happy.”

  16. PHARMACOLOGY

    How the Body's 'Garbage Disposal' May Inactivate Drugs

    1. Gretchen Vogel

    A protein sentry that triggers the liver's defense against chemical toxins can explain drug interactions—and an old legend

    Some 2000 years ago, King Mithridates of Pontus, a region on the Black Sea that is now part of Turkey, performed an astonishing trick. According to a legend immortalized in an A. E. Housman poem, the ambitious and warring monarch feared his enemies would poison him. To guard against this, he dosed himself with small amounts of poisons to build up his immunity. The technique worked: Mithridates survived the assassination attempt he predicted, and his name came to mean an antidote for poison.

    Molecular endocrinologist Ronald Evans now thinks he has a molecular explanation for Mithridates's invulnerability. Recent work by Evans at the Salk Institute for Biological Studies in La Jolla, California, and by other teams around the world is revealing the machinery of the body's defense against poisons and other foreign chemicals. The work, reported over the last year, helps explain not only an ancient riddle but also why taking certain drugs or herbs, like the popular St. John's wort, can render others ineffective.

    Scientists have known for years that the body has a chemical surveillance system in the liver. Sensing the presence of potentially dangerous chemicals, the liver cells crank up the production of an enzyme called CYP3A, which breaks down a host of compounds, including many toxins. “CYP3A is like the liver's garbage disposal,” says Steven Kliewer, an endocrinologist at GlaxoSmithKline in Research Triangle Park, North Carolina.

    Many scientists suspect that this “garbage disposal” evolved to fend off the countless toxins to which animals are exposed in the environment, including the poisons plants produce to avoid being eaten. But exactly how it works has long been a mystery. A key question is what receptors in the liver cell initially sense the toxin and alert the chemical police to seek and destroy it. Most scientists expected to find a suite of receptors, all tailored to recognize specific threats. But over the past few months, converging research by several teams suggests that just one protein—perhaps aided by a handful of assistants—can recognize the thousands or even tens of thousands of potentially harmful compounds present in the environment and prompt the liver to mount an all-out attack on them.

    One set of clues came from an unexpected line of research: Patients taking St. John's wort, a popular herbal remedy for depression. In late 1999 and early 2000, several papers reported that in some half-dozen patients taking St. John's wort, the blood concentrations of other drugs they were taking—including the asthma drug theophylline and the anticlotting drug warfarin—were dramatically reduced. Several women taking birth control pills reported breakthrough bleeding, suggesting that the pill's hormone levels had dropped. In another well-publicized example, two heart transplant recipients in Germany experienced life-threatening transplant rejections a few weeks after starting to take St. John's wort. Their physicians found that levels of the immunosuppressant cyclosporin had plummeted to half the normal dose (see sidebar).

    Many scientists suspected that St. John's wort was activating the CYP3A pathway, which would accelerate the breakdown of the other drugs. Intrigued, Kliewer and his Glaxo colleagues decided to test whether St. John's wort was working through the PXR receptor, a protein they had discovered in mice several years earlier and had been intensely studying ever since. Evans and his colleagues knew that PXR, which has a human counterpart known as SXR, triggered production of CYP3A. But they did not know what activated PXR in the first place.

    GlaxoSmithKline scientist Linda Moore headed off to the local pharmacy, where she bought three preparations of St. John's wort. When she tested their effect on the PXR receptor, she hit paydirt. “We found that it was extremely efficient at activating PXR,” says Kliewer. “Rarely in science do things work the first time, but this was really dramatic.” The team tested several active components of St. John's wort and found that almost all the PXR activity was caused by a molecule called hyperforin—the same compound that many scientists think bestows St. John's wort's antidepressant activity. St. John's wort, it seems, triggers PXR, which cranks up production of the CYP3A enzyme, which in turn breaks down cyclosporin, idinavir, and a host of other drugs.

    What's more, says Evans, PXR seems to be almost solely responsible for activating the chemical police system. His evidence comes from experiments with knockout mice done to further characterize PXR. In July, Evans and his colleagues reported that mice lacking the PXR gene did not respond to compounds that typically kick off the CYP3A system in mice. But when the researchers knocked out PXR and inserted SXR, the animals had a “humanized” CYP3A response: They still failed to respond to classic triggers of the mouse CYP3A system, but they reacted strongly to at least a dozen compounds that activate the human system, including the antibiotic rifampicin—notorious for triggering drug interactions. Because switching a single gene caused such a dramatic change, Evans argues that PXR and SXR are the primary sentries for the CYP3A system. The overall system “is a lot simpler than we thought,” Evans says.

    There is evidence that SXR does not work entirely alone, however. In October, a team led by David Moore at Baylor College of Medicine in Houston, Texas, reported in Nature that another gene called CAR seems to play a similar role, activating an enzyme called CYP2B in response to phenobarbital. CYP2B, in turn, breaks down a number of compounds, including cocaine. But it seems to have a narrower scope than SXR does, Kliewer says.

    No one yet understands how SXR and PXR can respond to so many different chemicals. Kliewer suspects that the receptor may have an especially large binding site, which can accommodate a variety of molecules. To test that theory, scientists must obtain the crystal structures of the receptor with many different ligands—a daunting project that several teams are working on, says Kliewer. He expects an answer in the coming year.

    No matter how the receptor works, Evans predicts that his humanized mouse model will be a boon to pharmaceutical companies. By testing compounds in these knockout mice, companies can determine which ones activate the CYP3A system and thus potentially interfere with other medications. Companies today use cultured human cells to test for a range of CYP gene activation, but Evans says such tests are more variable than a humanized mouse might be.

    Others are not convinced. The mouse model is “a great first step,” says Mitch Lazar of the University of Pennsylvania School of Medicine, but he expects that research will uncover additional receptors, such as the CAR gene, that play an important role in drug interactions.

    However many receptors are involved, the defense system worked for Mithridates—if the legend can be believed. Evans theorizes that the small doses of poison Mithridates ingested primed his SXR receptor. With the CYP3A system on high alert, Evans says, otherwise deadly doses were easily neutralized. As A. E. Housman describes it:

    They put arsenic in his meat

    And stared aghast to watch him eat;

    They poured strychnine in his cup

    And shook to see him drink it up:

    They shook, they stared as white's their shirt:

    Them it was their poison hurt.

    —I tell the tale that I heard told.

    Mithridates, he died old.

  17. PHARMACOLOGY

    A Worrisome Side Effect of an Antianxiety Remedy

    1. Gretchen Vogel

    As reports came in on drug interactions with St. John's wort, the National Institutes of Health (NIH) and the Food and Drug Administration (FDA) went on alert. In February, NIH scientists reported in The Lancet that, in healthy volunteers, St. John's wort cut in half the blood levels of the antiretroviral drug idinavir commonly used to treat HIV infections. In the same issue, German doctors reported that St. John's wort had caused levels of an immunosuppressant drug to plummet in two heart transplant recipients. That week, the FDA issued an official warning to doctors and pharmacists noting that the herb could interfere with dozens of drugs, including the antiseizure medication phenobarbital, the breast cancer drug tamoxifen, the oral contraceptive ethinyl estradiol, and antiretrovirals used to treat AIDS.

    As scientists discovered a few months later, St. John's wort triggers production of an enzyme called CYP3A, which breaks down potential toxins in the liver. In addition to warding off poisons, the CYP3A system also helps to metabolize hormones such as estrogen, testosterone, and their precursors. For that reason, the FDA now warns that women taking birth control pills should not take St. John's wort, because CYP3A breaks down the synthetic hormones designed to prevent pregnancy. No one has done a systematic study of the pill's failure rate in women taking the herb, says complementary medicine specialist Edzard Ernst of the University of Exeter in England, but “there could be a few ‘St. Johns’ walking the street now.”

    The work has uncovered an unexpected potential benefit as well. The latest work by teams led by Steven Kliewer at GlaxoSmithKline in Research Triangle Park, North Carolina, and Ronald Evans at the Salk Institute for Biological Studies in La Jolla, California—which they have described at several meetings—shows that the CYP3A system also helps break down bile acids. Kliewer believes that St. John's wort might be useful in alleviating an especially difficult-to-treat condition called cholestasis, which occurs when people can't break down bile acids properly and toxic byproducts build up in the liver. “There are anecdotal reports that St. John's wort is useful for treating liver diseases,” Kliewer says. He suspects these reports might come from cholestasis patients whose CYP3A production has been boosted.

  18. Microquasars Raise Megaquestions

    1. Mark Sincell*
    1. Mark Sincell is a science writer in Houston.

    To uncover the machinery behind galaxy-spanning quasars, astrophysicists are scrutinizing their miniature counterparts—only to find that they pose puzzles of their own

    Contrary to popular belief, black holes are finicky eaters. Although the voracious billion-solar-mass monsters that power distant quasars can devour the equivalent of one sun per year, they may spit out as much as they swallow.

    For decades, radio astronomers have seen narrow jets streaming out of the centers of quasars and pooling up in vast “lobes” that resemble the outstretched ears of an elephant. Despite intense study, however, “jets have resisted understanding,” says astrophysicist Jean Swank of the Goddard Space Flight Center in Greenbelt, Maryland. What they are made of, why they form, what keeps them going—all are unsettled questions.

    The problem is that quasar jets change very slowly. Although individual blobs in the otherwise smooth jet sometimes appear to travel faster than the speed of light—an optical illusion called superluminal motion, produced when an object travels toward Earth at nearly the speed of light—the jets are very long. A single lobe can be as long as the spiral arm of a galaxy. As a result, it can take decades for astronomers to notice any movement or change in the shape of a quasar jet.

    So Felix Mirabel of France's Atomic Energy Commission (CEA) in Saclay and Luis Rodriguez of the Institute of Astronomy in Morelia, Michoacán, Mexico, were thrilled when, in 1994, they spotted a pair of miniature radio jets erupting from a nearby galactic black hole candidate named GRS 1915+105. Like the jets from its grandiose relatives, the newly christened microquasar emitted an occasional blob that raced down the length of the jet at superluminal speeds. In fact, the tightly focused jets were almost exact small-scale replicas of parsec-sized quasar jets, with one crucial difference: They evolved in minutes, not years.

    “Microquasars are an ideal test laboratory for jet formation,” says Cornell University astrophysicist Stephen Eikenberry. Their appetites whetted, astronomers started avidly hunting for more. Since Mirabel and Rodriguez's discovery, concerted observations from the ground and from space with radio, infrared, optical, x-ray, and gamma ray telescopes have turned up about a dozen objects with the telltale microquasar radio jets.

    Just how much microquasars have to say about normal-sized quasars, however, is hotly debated. Do they really hold the key that will unlock the mysteries of jet formation in quasars· Or are the apparent similarities just a coincidence· Answering these questions is one of the primary goals of a new generation of orbiting x-ray telescopes, including the Chandra X-ray Observatory, the Rossi X-ray Timing Explorer, and the European Space Agency's XMM-Newton and Integral satellites.

    Some astronomers think the family resemblance will turn out to be spurious. “So far, nothing we know about quasars has been changed by observing microquasars,” says Bruce Margon, an astronomer at the University of Washington, Seattle. The black hole that powers a microquasar, Margon notes, is about as massive as a star; the hole in a “real” quasar is a billion times larger. “Very few physical processes scale linearly over nine orders of magnitude,” he says. The dining habits of the two types of objects also seem to set them apart. Quasar black holes are isolated beasts that feed on hot gas dribbling in from a surrounding cloud. Microquasar black holes are more social: Every known microquasar orbits a windy gas-giant companion star that dumps material into the black hole.

    Whatever its source, scientists believe that as gas approaches the central black hole of either a quasar or a microquasar, it collapses into a disk that whirls around the hole in much the same way as the planets orbit the sun. Unlike the planets, however, the viscous gas in a so-called accretion disk gradually loses energy and spirals toward the hole. The lost orbital energy heats the disk, so the temperature of the gas increases the closer it gets to the black hole. As the gas prepares to drop into the black hole, its temperature skyrockets toward almost 1 billion degrees and radiates copious x-rays.

    The jets of a quasar, many theorists suspect, result from the way the gas interacts with the loops of its own magnetic field. The rotating disk winds the field loops like the rubber band in a toy airplane. The magnetic tension increases as the field loops approach the black hole, weaving the loops into magnetic braids that pop out perpendicular to the disk. Hot, radiating gas flows up from the disk and through the braided field lines like water through a pipe, forming the illuminated, magnetized fountains that astronomers call jets.

    Theorists think similar scenarios can explain microquasars, with one key difference: Quasar jets appear to be steady and unchanging, whereas microquasar jets are anything but. In GRS 1915+105, for example, approximately every 30 minutes a new blob of radio emission materializes at the base of the jet, accelerates to superluminal speeds, and rockets outward along the jet, fading as it goes. In other microquasars, the light from the jets fluctuates wildly. By comparing radio and x-ray observations of microquasars, astronomers have found evidence that the superluminal blobs and variations in x-ray brightness both result from processes that take place when a microquasar flip-flops between two very different states.

    “The x-rays from accreting black holes in our galaxy come in two distinct forms,” explains Rob Fender, an astrophysicist at the Astronomical Institute-Anton Pannekoek (AIAP) in Amsterdam. In the so-called high/soft state, the disk shines brightly in low-energy “soft” x-rays. As the microquasar enters the low/hard state, on the other hand, the x-rays dim but their spectrum shifts to higher energy “hard” x-rays. Now, independent observations by Fender, Eikenberry, Mirabel, and their collaborators indicate that the superluminal radio blobs from GRS 1915+105 form as the microquasar makes that transition. And Michel Tagger, an astrophysicist at the CEA, thinks he can explain why.

    A theory developed by Tagger's team and confirmed by computer simulations shows that magnetized accretion disks naturally spawn spiral waves, in much the same way as the Milky Way disk generates spiral arms. In Tagger's model, a microquasar spends part of its time in the high/soft state, during which the waves sweep the magnetic field inward toward the brink of the black hole—the so-called “innermost stable orbit,” a mere 100 kilometers from the hole. Closer in, the black hole's gravity grows so strong that nothing can remain in a circular orbit; the accreting gas plunges straight into the hole.

    The magnetic field, however, doesn't follow the doomed matter. Instead, it piles up at the edge of the hole until the increasing tension in the twisted field suddenly snaps it like a rubber band that has been stretched too far. The explosion destroys the soft-x-ray- emitting inner part of the disk, allowing the hard x-rays to shine through and returning the microquasar to the low/hard state. At the same time, the energy of the broken field launches a blob into the jet, as observed in some microquasars. Astrophysicists say that if the theory can be extended to quasars, it might explain the mysterious dichotomy between radio-loud quasars, which emit jets, and the more numerous radio-quiet ones, which have no jets at all. Radio-quiet quasars could simply be in the supermassive equivalent of the high/soft state.

    Tagger's theory rests on one big assumption. For it to work, the accretion disk must extend all the way down to the innermost stable orbit of the black hole. In the gravitational hurly-burly near a black hole, however, any number of forces could destroy or scatter the gas en route. Does it really reach the crucial 100-kilometer point· Tiny variations in the x-ray flux from the microquasars are whispering that the answer might be yes—at least some of the time.

    The gravitational pull of a microquasar black hole forces disk material to orbit the hole approximately 1000 times per second, just as the sun's gravity pulls Earth through one complete revolution every year and makes the planets in tighter orbits speed around much more quickly. A tiny clump of gas in the innermost orbit would hurtle along at nearly the speed of light, and on each pass it would shine a beam of x-rays at Earth like the headlights of a car on a circular track.

    In fact, signals resembling such x-ray “headlights” have been detected. Astronomers studying microquasars have measured x-rays that rise and fall at a rate that wanders around a fixed central frequency—sometimes slightly higher, sometimes slightly lower. First discovered in 1985, these quasi- periodic oscillations (QPOs) have now been found in most known microquasars. The typical QPO frequencies are suggestively close to the period expected for a lump of gas in the innermost stable orbit of a black hole. The hitch, so far, is that the orbiting-gas model is only one of many possible explanations of the variations in frequency. Those variations—the “quasi” in quasi-periodic—make scientists wary of overinterpreting the results. “The frequencies of these QPOs are definitely in the right ballpark, but other processes could mimic the effect,” says AIAP astrophysicist Michiel van der Klis.

    Another test of the magnetic-jet theory is to measure the speed of microquasar jets. Tagger's model predicts that the disk-hole system should spew out material at nearly the speed of light. The superluminal blobs detected in three microquasars fit that picture very well. Calculations show that to create the illusion of faster-than-light travel, those jets must be coursing along at 80% to 90% of light speed, at minimum. The velocity has been measured for only one microquasar, however. “If we had even one more velocity, we could at least ask the fundamental question: Are all the velocities the same·” says Margon. “Right now, we can't even do that.”

    Clocking a jet's speed directly is difficult, because microquasars' distances are poorly known. In principle, exact measurements could come from the jets' light. A stationary hot gas of atoms radiates light at specific frequencies that form bright “emission lines” in the spectrum of light from the gas. The emission lines of two oppositely directed high-speed jets of hot gas, however, split into pairs. The same Doppler shift that raises the pitch of an approaching train whistle also increases the frequency of the emission lines from a jet pointed in our direction. The emission lines from the receding jet drop to lower frequencies. The difference in the two Doppler-shifted line frequencies is directly proportional to the jet velocity.

    So far, astronomers have found the revealing line pairs in only one object: SS433. Unfortunately, that reading has just sown more confusion. SS433's emission lines show that the jet streams outward at one-quarter of the speed of light—fast, but not as fast as theory predicts. And there is another problem: Some astronomers suspect that SS433 is an anomalous object that contains not a black hole but a neutron star— “the worst example” of a microquasar, Margon says.

    Help may come from Chandra, which has recently turned up encouraging hints of line pairs in several other microquasars. “We found suggestive evidence for the lines in the microquasar 1E1740.7-2942,” says astrophysicist Wei Cui of Purdue University in West Lafayette, Indiana. “We now have 10 times more telescope time, so we should have a definitive answer next year.”

    Until that answer comes, researchers can only speculate as to whether microquasars truly are miniature quasars. Dimitrios Psaltis, for one, is beginning to suspect that the answer isn't a simple yes or no. Psaltis, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, in collaboration with van der Klis and Tomaso Belloni of the AIAP, has found evidence that the pattern of QPOs varies smoothly from neutron stars to black holes. The result suggests that microquasars are not exactly the same as either neutron stars or quasars, but instead form a link in a chain of jet-producing compact objects that extends from stellar-mass neutron stars all the way to the supermassive quasars.

    Van der Klis acknowledges that the proposal is tentative and needs further investigation. “Some say this is just a coincidence, and others build entire theories out of it,” he says. “That is just the way it is in this field right now.”

  19. Astronomical Odd Couple? Or Alter Egos?

    1. Govert Schilling*
    1. Govert Schilling is an astronomy writer in Utrecht, the Netherlands.

    While theorists try to bring them under one explanatory umbrella, the cosmic rarities known as SGRs and AXPs seem to insist on their differences

    To high-energy astrophysicists, the calm beauty of the night sky is the world's grandest illusion. “It's a wild animal park out there,” says Chryssa Kouveliotou of NASA's Marshall Space Flight Center in Huntsville, Alabama. Kouveliotou should know. She and a handful of colleagues worldwide study two of the wildest, most elusive creatures in the universe. Known as soft gamma repeaters and anomalous x-ray pulsars—SGRs and AXPs for short—the two classes of objects have teased astronomers for years with tantalizing similarities that may, or may not, be family resemblances. For the sake of simplicity, astrophysicists would love to show that SGRs or AXPs are special cases of the same theory, or different stages in each other's life cycle. So far, though, attempts to establish such an evolutionary link have run up against equally frustrating differences between the two enigmatic objects. And some recent evidence indicates that they may not be related at all.

    The likenesses are clear: Both types of objects are rare; astronomers know of only four SGRs and six AXPs. Both are found alone, apparently in association with young supernova remnants. From variations in their x-ray output, astronomers know that both spin with periods of between 5 seconds and 12 seconds, and both are slowing down considerably.

    The main differences between them are that SGRs have a “harder” spectrum (one containing more high-energy radiation), and, unlike AXPs, they erupt into bursts of explosive activity. But those distinctions may not be hard and fast. The first identified SGR—an object known as SGR 0526-66 in the Large Magellanic Cloud—would be classified as an AXP if it were discovered today, Kouveliotou says. No one has detected a burst from 0526-66 since 1983, and a team led by Shrinivas Kulkarni of the California Institute of Technology in Pasadena, which recently observed the object using NASA's Chandra X-ray Observatory, reports that its spectrum turns out to be very soft.

    “The similarities of SGRs and AXPs argue that they are one kind of beast,” says Robert Duncan, a theoretical astrophysicist at the University of Texas (UT), Austin. And the heart of the beast, everyone agrees, is a neutron star—the whirling, superdense corpse of a massive star that exploded as a supernova at the end of its short life. Beyond that, though, confusion begins. At issue is how the two objects generate the powerful radiation in their spectra. The reigning model of SGRs says that it comes from starquakes on the star's intensely magnetic surface. A popular model for AXPs holds that the radiation emanates from gas sucked in by the star's enormously powerful gravity. If the beasts are indeed related, at least one of the models must be wrong. Which one· The experts disagree, often sharply.

    Surging starquakes

    The SGR saga began in 1979, when orbiting satellites and interplanetary space probes registered a couple of powerful bursts of energetic x-rays and gamma rays. No one knew what they were. Most astronomers classified them as gamma ray bursts. (See the Review by Peter Mészáros on p. 79.) One of those explosions, however, was special. Observed on 5 March 1979, it appeared much brighter than any other gamma ray burst detected so far, it contained more low-energy radiation, and it went off again and again, producing 16 bursts over a 4-year period. What's more, whereas “normal” gamma ray bursts occur in “empty” spots on the sky, this one—called SGR 0526-66, after its position in the sky—resided in a young supernova remnant in the Large Magellanic Cloud, a companion galaxy of our Milky Way, some 170,000 light-years away.

    By 1986, gamma ray burst researchers had identified two more sources with the same characteristics: multiple short bursts, first observed in 1979; a “soft” spectrum (one with relatively high levels of low- energy radiation); and a possible association with a supernova remnant. The three eccentrics were christened “soft gamma repeaters,” although Duncan says “hard x-ray flashers” would have been more descriptive. (In the electromagnetic spectrum, hard x-rays grade into soft gamma rays.)

    UT's Robert Duncan, together with Christopher Thompson of the Canadian Institute for Theoretical Astrophysics in Toronto, speculated that the repeating bursts were caused by starquakes on highly magnetized neutron stars. They had predicted on theoretical grounds that such bizarre objects ought to exist; in a landmark 1992 paper in the Astrophysical Journal, they named them “magnetars.”

    Like other neutron stars, magnetars are born after a massive star explodes into a supernova. The core of the star collapses into a rapidly rotating ball of densely packed neutrons, surrounded by a kilometer-thick crust of solid iron. The result is the densest object in the universe—the mass of a star packed into a ball no larger than Washington, D.C., every cubic centimeter of which weighs 100 million tons.

    As their rapid radio pulsations show, neutron stars spin madly, some of them hundreds of times per second. In magnetars, the initial rotation rate of the progenitor star is high enough to turn the conductive liquid interior of the neutron star into a dynamo that can create a magnetic field on the order of 1015 gauss. That's 1000 times as strong as the field of a radio pulsar, or as powerful as 10 trillion refrigerator magnets. According to Duncan and Thompson's magnetar model, such a superstrong field would periodically deform and crack the neutron star's crust, producing starquakes and seismic waves that release tremendous bursts of energy, emitted in the form of fast-moving elementary particles and high-energy radiation.

    The magnetar theory got a boost in 1998, when Kouveliotou and her colleagues discovered that one of the SGRs had slowed by about 0.1% in just a few years. Assuming that the slowdown was the result of magnetic braking (the only viable explanation), Kouveliotou deduced a magnetic field strength of 800 trillion gauss—in good agreement with the magnetar model. “I consider the evidence compelling,” says Duncan. Most other astrophysicists agree; currently, magnetars stand all but unrivaled as a theoretical explanation for SGRs.

    Ubiquitous source

    While some scientists were closing in on SGRs, others were adding AXPs to the astrophysical bestiary. X-ray satellites first spotted AXPs in the 1970s and 1980s, although astronomers didn't realize they were a class of their own until 1995—and even then they disagreed about what they were. “Normal” x-ray pulsars are rapidly spinning neutron stars in binary systems. Their x-rays are emitted by hot gas from the companion star, which accumulates into an accretion disk and heats up as it falls toward the neutron star. Although the AXPs show no signs of companions, many astrophysicists suspect that they are powered by accretion, too.

    At the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, Pinaki Chatterjee, Lars Hernquist, and Ramesh Narayan have proposed a model in which AXPs are fueled by debris from the supernova explosion that produced the neutron star. “Accretion is a ubiquitous energy source in the cosmos which powers most x-ray pulsars that we see,” says David Marsden of NASA's Goddard Space Flight Center in Greenbelt, Maryland, who has presented similar ideas. “Therefore, there is a strong desire to explain AXPs in terms of accepted theoretical models.”

    Other models, however, have reared their heads. A few years ago, Bohdan Paczyn<<ski of Princeton University proposed a radically different idea. In his scenario, AXPs are powered not by infalling gas but by the loss of rotational energy from the spinning object itself. A small neutron star would have too little angular momentum to do the trick, Paczyn<<ski calculated; for his mechanism to work, the object would have to be something with about the same mass but significantly larger—perhaps an exotic object formed by the merger of two white dwarfs.

    Marten van Kerkwijk of Utrecht University in the Netherlands, for one, is unconvinced. The white-dwarf model has many problems, he says, the chief one being that it cannot explain why some AXPs are associated with young supernova remnants. But Van Kerkwijk thinks the accretion model has fatal flaws, too. In fact, he says, new observations all but rule it out.

    Working with Ferdi Hulleman of Utrecht University and with Kulkarni, Van Kerkwijk used the 10-meter Keck telescope at Mauna Kea, Hawaii, to identify the optical counterpart of 4U 0142+61, one of the six known AXPs. Writing in the 7 December issue of Nature, they state that the optical counterpart is much dimmer than would be expected from the accretion model. Duncan agrees: “The fossil disk model is disproven,” he says.

    To explain AXPs, Duncan and Van Kerkwijk look to the model that works so well for SGRs: magnetars. Theoretical models, they point out, show that magnetars are short-lived. After 10,000 years or so, the stars cool enough that their magnetic energy source turns off. Might that explain how SGRs evolve into AXPs· A magnetar could experience starquakes and produce soft gamma ray bursts for something like 10,000 years and then stop bursting when the magnetic energy runs down. During the next 100,000 years or so, the magnetic field would still be strong enough to produce steady, pulsed x-ray emission, and the magnetar would be visible as an AXP. Still later, it would fade completely and become practically invisible.

    Soulmates or strangers?

    Convincing as this scenario may seem, many x-ray astronomers have their doubts. “Magnetars are hypothetical objects,” Chatterjee says, pointing out that the only evidence of the ultrastrong magnetic fields that the objects are said to harbor comes from timing the rotation of pulsars, not from direct measurements. As for 4U 0142+61, he adds, more detailed observations at other wavelengths are needed to determine how seriously it affects the accretion model.

    NASA's Marsden agrees. “Only if the accretion model is strongly and unequivocally ruled out will new models be widely accepted,” he says.

    Meanwhile, some surprising recent evidence suggests that the two types of mystery objects may be different creatures altogether. Bryan Gaensler of the Massachusetts Institute of Technology in Cambridge studied SGRs and AXPs associated with supernova remnants. From the ages and distances of the supernova remnants and the displacement of the neutron stars from the remnants' centers, he calculated that AXPs are rushing away from the remnants at speeds on the order of 500 kilometers per second. That is not unexpected, as neutron stars are believed to be born with high “kick velocities” from the supernova explosions that create them. What is surprising, though, is that SGRs appear to be moving four times as fast.

    That velocity difference poses a tough choice, Kouveliotou says. If astronomers have matched the neutron stars with the right supernova remnants, then it's hard to see how SGRs and AXPs could be related and yet travel at such different velocities. Conversely, if they are related, then for at least one of the two types of objects, “the apparent association with supernova remnants must be bogus,” says Kouveliotou.

    Van Kerkwijk admits that the supernova link could be stronger: Although most SGRs and AXPs seem to be related to supernova remnants, only for two of the six known AXPs and two of the four known SGRs is the evidence clear-cut. For a third SGR, the neutron star is so far away from the supernova remnant that it must be moving at 2900 kilometers per second if the two objects are indeed related. Kevin Hurely of the University of California, Berkeley, hopes to check that figure by using Chandra to measure the displacement of the x-ray source across the sky.

    In the end, the links, if any, between AXPs and SGRs will come from that familiar wellspring: more data. Unfortunately, even the most sensitive orbiting observatory or ground-based telescope can't detect the superstrong magnetic fields that would prove or disprove the magnetar model. But they might reveal whether AXPs draw power from accretion, or whether any of them is consorting with one of Paczyn<<ski's white-dwarf mergers. If the observations rule out such alternatives, magnetars will look better and better to astrophysicists.

    And if the magnetar model prevails· One consequence, Duncan says, is that magnetars might not be as rare as they seem. From their theoretical life-span and the known number of SGRs and AXPs, it's straightforward to calculate that a new magnetar should be born in the Milky Way galaxy about every 1000 years. Ten million “dead” magnetars might well be zooming through interstellar space at this moment, Duncan says—black beasts camouflaged by cosmic night.

  20. Tatars' Saucy Project Takes on the World

    1. Richard Stone

    A dark horse called Dulkyn aims to put the Republic of Tatarstan in the race to detect gravitational waves

    KAZANOn the edge of this city on the Volga River, in a cavernous underground hall off limits to most visitors, stand two rows of what look like massive tombs. The structures—12 pale yellow cabins, boxy and featureless—belong to the State Institute of Applied Optics. Eleven of them house some of the most advanced optical equipment in the world: laser setups for carving diffraction gratings and holographic plates, onetime components of a Soviet missile defense shield then in development.

    Each cabin rests on a separate foundation to reduce the effects of seismic vibrations; inside, temperatures are kept precisely at 19 degrees Celsius. Such a sanctuary is necessary for reliably cutting tiny diffraction patterns—and essential to an experiment in the lone cabin that isn't part of the production complex. Here, in a room within a room, a novel project aims to do something never done before: use lasers to detect the pull of the moon on Earth's gravitational field. The Kazan team members call their experiment, which they hope to undertake this fall, “the lunar test.” Some experts, however, call it lunacy.

    “A few crazy ideas turn out to be genius. This one is just crazy,” says Moscow State University physicist Vladimir Braginsky, the dean of Russian gravitational-wave researchers (see sidebar). He disparages the Kazan group's chances of achieving its ultimate goal, which is to modify a laser setup to detect ripples in the fabric of space-time—specifically, low-frequency gravitational waves emanating from the outer-space objects known as binary pulsars.

    But even if the experiment fails, many others say it's worth supporting. The laser system could serve as a gyroscope that would “give a good measure of Earth's rotation,” says Karsten Danzmann, one of the architects of GEO-600, a British-German gravitational-wave detector. “It's a very courageous idea,” adds Philippe Tourrenc of Pierre and Marie Curie University in Paris, a founding father of the French-Italian VIRGO detector and one of the few westerners who has had a firsthand look at the Kazan setup.

    For 4 decades, physicists pursuing this goal have built ever bigger and more elaborate experimental facilities with growing confidence that they are on the verge of plucking a relativistic gravitational signal from a sea of earthly noise. The stakes are high. The first group to measure gravitational waves from any source will blaze a trail into uncharted astrophysics and will almost certainly bag a Nobel Prize. Major efforts now under way include VIRGO, a laser interferometer being built near Pisa; TAMA, a Japanese interferometer nearly finished outside Tokyo; and the GEO-600 interferometer near Hannover, Germany. Grandest of all is the $365 million Laser Interferometer Gravitational-Wave Observatory (LIGO), a U.S.-led effort to use laser beams to detect high-frequency gravitational waves from supernovas (Science, 21 April, p. 420). Russia's two leading gravitational-wave teams—Braginsky's group and another led by Alexander Sergeev at the Institute of Applied Physics in Nizhny Novgorod—have signed on to LIGO.

    By contrast, the Kazan group's puny $1 million tabletop experiment, dubbed “Dulkyn,” is a definite dark horse. Dulkyn is a “heroic effort on a low budget,” says Danzmann, who predicts that noise will doom Dulkyn's gravitational-wave quest. Most others say they know too little of Dulkyn to prognosticate. For better or worse, that will soon change: The Kazan group has been invited to present the concept in Perth, Australia, in July 2001, at the annual Edoardo Amaldi Conference, the main meeting of the world's gravitational-wave researchers. Ending Dulkyn's decade of isolation could lead to collaborations and financing—or, if critics like Braginsky are right, send it right back into obscurity.

    Like the optics institute that houses it, Dulkyn is a child of the Soviet military- industrial complex. Its roots date to the early 1980s, when military scientists launched an effort to develop a new kind of radar to scan the ionosphere for incoming missiles. The results, if any, remain secret. But as a spin-off of the project, Zufar Murzakhanov and theoretician Alexander Balakin of Kazan State University (KSU) proposed a scheme in 1989 for probing Earth's gravitational field and possibly exploiting gravitational waves as a navigation tool. Just months after the Soviet Council of Ministers approved the project and planned to allot it a generous 5 million rubles in funding—roughly the same sum in U.S. dollars at the time—the Soviet Union dissolved, dragging with it into the abyss most funding for defense research.

    Deprived of military support, Murzakhanov and Balakin opted in on the civilian hunt for gravitational waves. That itself was not a first for Kazan, a city with a rich history in the sciences. In the early 1960s, Alexei Petrov—known today for a theorem in his name defining three types of Einsteinian curved spaces—had founded KSU's department of relativity theory and gravitation and had planned to build a gravitational-wave detector. But the project was abandoned after Petrov moved to Kiev in 1965.

    Reviving gravitational-wave research in Kazan meant finding a new source of funding. Shunned by Moscow, Murzakhanov and Balakin appealed to the president of the Republic of Tatarstan, a semiautonomous region within the Russian Federation. Murzakhanov remembers how he was grilled by Tatarstan cabinet members: “The first pointed question was, ‘What will this project give to society·’ I told them the point is to investigate our universe and gather knowledge. They looked at us like we had psychiatric problems.”

    Still, the upstart project appealed to top officials eager to put Tatarstan on the map. The independent-minded republic—which last year embarked on a program to replace the Cyrillic alphabet with Latin script, and where most public buildings fly Tatarstan's green, white, and red striped flag, rather than the Russian flag—was filled with a defiant civic pride, and it had oil revenue to throw at a long shot that would win international acclaim if it succeeded.

    Murzakhanov and Balakin assembled a team and, along with Rinat Daishev and Alexander Skochilov, created the Gravitational Wave Research Center Dulkyn, after the Tatar word for “wave.” They struck upon a system that, they claim, should be able to overcome the key hurdle of all gravitational detectors—measuring minuscule signals in a thicket of noise—by accumulating the signal over time. Dulkyn has no chance of sensing the fleeting bursts of high-frequency gravitational waves that LIGO is designed to detect. Rather, the Kazan group is hoping to feel low-frequency gravitational waves kicked up by space-time-warping binary pulsars. These vibrations are the quarry of LISA, a European-U.S. interferometer array planned for launch later this decade (Science, 10 December 1999, p. 2060). Composed of three satellites in a triangular formation 5 million kilometers apart, LISA will orbit far above any ground-based noise, such as low-frequency thermal fluctuations, that would tend to mask the signal.

    Dulkyn, if it is completed, will substitute patience for LISA's sublime isolation. In the experiment, one laser beam will traverse a 5-meter-long perimeter of a pentagonal array of mirrors. A second beam, of a different polarization, will be diverted from this path by diffraction gratings and run a longer route. Gravitational waves will shift, ever so slightly, both the wave phase and the resonant frequency of these beams as they are generated by the laser, says Balakin. In the beam traveling the perimeter route, the equal distances between the five mirrors will serve to damp the gravitational-wave-induced shifts, like ironing out wrinkles in a shirt. But in the internal route, where the beam travels farther between mirrors after being diffracted, the phase shifts will persist and intensify until, after days or weeks, Balakin argues, they will be discernible after subtracting the effects of noise seen in both beams.

    The approach “is extremely elegant in the finest traditions of experimental physics,” says physicist Ed Langham, a former director of satellite operations for the Canadian Space Agency who, under the auspices of the Canadian Executive Service Organization, spent 2 weeks in Kazan in 1999 helping Dulkyn draft a business plan.

    Before embarking on the gravitational-wave experiment, however, the Kazan team will undertake its lunar test. Conceived by Skochilov, the test languished during a 2-year funding drought following the August 1998 ruble crash, but it revived a few months ago when Dulkyn received a cash injection from the local government following a visit to the facility by Russian Vice Premier Ilya Klebanov. The team will use the money to put the finishing touches on a modified laser system designed to detect shifts in wave phase in the generation frequency of a laser beam, induced by 12-hour lunar tides.

    Success would by no means guarantee that Dulkyn can detect relativistic gravitational waves from binary pulsars, which would be far more subtle. But it would confirm the principles of Dulkyn, says Daishev, and give the team confidence to undertake the relativistic experiment. And even if Dulkyn never detects a single gravitational wave, the work could yield practical payoffs, such as gyroscopes or gravimeters for use in oil exploration and geophysical studies.

    Assuming the project does clear its lunar hurdle, the Kazan scientists plan to raise about $350,000 to complete their pentagonal laser system. They hope to install the instrument in a facility to be built underground on the Volga, 60 kilometers south of Kazan. If all goes well, Dulkyn's first crack at detecting gravitational waves could come in 2003, soon after LIGO is operating fully.

    Could the Tatar David possibly beat the American Goliath· “Only a few people will bet that gravitational waves are first detected by Dulkyn, but this is not an argument against the project,” says Winfried Zimdahl, a physicist at the University of Konstanz in Germany who visited Dulkyn last year with two colleagues and wrote a letter supporting it to the Tatarstan Academy's president. Other experts are more skeptical. “It's a pity, but there seems to be some law that says [a gravitational-wave detector] has to be big,” says physicist James Hough of the University of Glasgow. Still, Zimdahl sees no harm in helping out an unconventional project that challenges the establishment. “After all,” he adds in a playful nod to another underdog, “David is by far the more charming character!”

  21. Keeping the Beat in a Noisy World

    1. Richard Stone

    MOSCOWVladimir Braginsky and his team do their best work in a Stalin-era bomb shelter. In the basement of the towering main building of Moscow State University, in a room once stocked with provisions for professors to ride out a nuclear war, the physicist and his research group have built the world's steadiest pendulum.

    Braginsky and his device are at the vanguard of an effort to tune in to gravitational waves from space. A decade ago, Russia's most prominent gravitational-wave researcher realized that only a multinational effort—and massive amounts of cash—would overcome the technical hurdles that prevent scientists from perceiving these ripples in space-time. So he cast his lot with the massive U.S.-led Laser Interferometer Gravitational-Wave Observatory (LIGO), which aims to measure such perturbations by reflecting laser beams back and forth along two 4-kilometer tunnels. The sharp-witted Moscow State professor is everything that his colleagues building a detector in Kazan (see main text) are not: a well-known player who's embraced by the scientific community.

    Braginsky's forte is ferreting out sources of noise that obscure gravitational-wave signals. His main contribution to LIGO has been to attack the perturbations affecting the mirrors that bounce the laser beams along their way. The mirrors, freely suspended in the tunnel, will wiggle ever so slightly when jostled by a gravitational wave—a motion that will cause the laser light to change phase by about a trillionth of its wavelength. (The wavelength of light is about half a micrometer, or 1/80 the width of a human hair.) To make such subtle shifts detectable, Braginsky must tackle everything from thermal vibrations to quantum fluctuations.

    “We're living in a hot, noisy world,” he says. One source of noise is the Brownian motion of the mirror's molecules. There are two ways to damp it: bring temperatures as near to absolute zero as possible, or weaken the connection between the mirror and the outside world. Braginsky has done the latter with his model system, in which a 2-kilogram weight, the pendulum bob, serves as a surrogate for a mirror. He has discovered that fashioning the bob—and the fiber it hangs from—out of extremely pure silica reduces Brownian fluctuations caused by friction of the bob's movement. (LIGO's mirrors are made from fused silica.) The best raw material, he found, comes from a Russian factory that once supplied silica fiber to the military for use in the Soviet equivalents of Tomahawk and cruise missiles.

    Damping Brownian motion also means setting up a “mismatching impedance.” In simple terms, Braginsky says, that means hooking up the pendulum “to a very heavy wall”—in this case, the bomb shelter's bulwark, a 1.6-meter-thick, 10,000-ton slab of concrete running the length of the building. Braginsky's team has diminished the friction in the pendulum's oscillations so effectively that, if left unchecked at room temperature, it would swing unassisted for 5.4 years—a world record. The LIGO team wants Braginsky to extend that so-called relaxation time to an even century.

    Braginsky himself has little time to relax, as his quest for near-perfection takes him down increasingly arcane byways of physics. A couple of years ago, he discovered that electrical fields induce transient quantum states on the surface of the bob that affect its motion. Reducing this noise “is terra incognita,” Braginsky says. “Nobody has done anything like this before.” But he clearly relishes this latest challenge.

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