To Celebrate a Big Anniversary, Scientists Ponder the Big Mysteries

Taking on some of the big questions that will drive science in the next quarter-century, top scientists predicted in a lively and wide-ranging session at the AAAS that new investigative tools and new ways of conceptualizing the world should help their fields to progress.

But the speakers at the 7 July session celebrating the 125th anniversary of the journal Science freely admitted areas of ignorance and suggested that answers to some of the most challenging questions—such as the biological basis of consciousness or whether the physical laws of nature can be unified—may well require new approaches and new vocabularies not yet imagined.

Marc Vidal, director of Dana-Farber Cancer Institute's Center for Cancer Systems Biology, noted that in 1905, the 25th anniversary of Science, the word "gene" was not yet in use; in 1930, the 50th anniversary, "genome" was still unknown; in 1980, the 100th anniversary, "proteome" had not yet been coined

Vera Rubin, an astronomer at the Carnegie Institution of Washington, also mentioned the likelihood that researchers in her field will be using terms not yet invented. Rubin's work supplied observational evidence that 90 percent or more of the universe is made of unseen "dark matter" that has gravitational effect on the visible objects such as galaxies.

Just what that dark matter is remains a mystery. Some specialists have suggested there may be as-yet undiscovered particles, called Weakly Interacting Massive Particles, or WIMPs, which could account for the unseen matter.

The longer the mystery remains, Rubin said, the more open astronomers and cosmologists must be to more radical possibilities.

"Maybe there is no particle or matter that is dark matter," Rubin said. Maybe astronomers are making a mistake in their assumptions about the applicability of Newton's laws to very large structures in the cosmos, she said. "We learned about 100 years ago that we had to change Newton's laws for the very small," Rubin said, with the development of quantum mechanics as the alternative. "Perhaps we will learn that we have to change Newton's laws for the very large."

S. James Gates, a theoretical physicist at the University of Maryland, spoke of tools that will allow scientists new glimpses of the cosmos in non-electromagnetic waves. A new facility called the Laser Interferometer Gravitational-Wave Observatory, or LIGO, recently began a search for postulated but as yet undiscovered gravity waves, which would be ripples in the fabric of space-time.

Data from LIGO can be cast in the range of human hearing, Gates said. "So you wind up hearing the universe," he said. "It's as if we were hearing whale song coming from stars and black holes as they collapse and collide. And if we are successful with these observatories, we will be actually making sonograms of the universe. It will be as if we were in a mother's womb making sonograms of our mother—the universe."

Whatever the future, Rubin said, the universe is likely much more complex than existing models suggest. And when it comes to formulating unified models that can describe the behavior of both the very large realm of the cosmos and the very small realm of the atom, the effort remains very much a work in progress. Albert Einstein's long-sought unified field theory continues to elude physicists.

Gates said that for more than 20 years, many experts have thought string theory might be the answer to unifying the forces and particles of nature in a single mathematical description. It still may be, he said, but without experimental evidence it remains unverified. Data from instruments like LIGO or the Large Hadron Collider, under construction near Geneva, Switzerland, may assist in fulfilling the quest begun by Einstein.

Neil Gershenfeld, director of MIT's wonderfully named "Center for Bits and Atoms," has been exploring the interface between information technology and the quantum world of the atom. He said scientists should be able to use computers and information sciences in novel ways in the future to explore the nature of matter.

Rather than using conventional computers to help facilitate their studies of nature, scientists "will be using the language of computation to understand nature itself," Gershenfeld said. In studies of molecular structure, for example, he said it is useful to think of nature as "an information transforming thing" that can be programmed to answer questions of scientific interest. The tiny cellular factory called the ribosome is, in essence, a computer, Gershenfeld said, that runs a program to reliably assemble the molecular building blocks that help make us who we are.

Gates agreed that there may be value in doing what he called computer-aided conceptualization studies in a variety of fields. "There's a new methodology out there that is waiting for us to explore," he said.

The age-old tension between reductionist and holistic approaches to scientific investigation also was a part of the conversation. In a session on memories, consciousness and human life, participants were asked whether the action of molecules and circuits in the brain can explain the conscious mind.

Mortimer Mishkin, a cognitive neuroscientist at the National Institute of Mental Health, responded: "I don't think that we have come to the point where we have any idea at all" on how a thought or judgment arises from the underlying neuromechanisms. But scientists assume there is a translational link, he said. "It is our faith that it is there," he said.

Michael Gazzaniga, a Dartmouth College neuroscientist, said he is confident that consciousness works as a distributed system in the brain and is amenable to scientific study. In contrast to Rene Descartes' 17th century declaration that the mind and body are entirely separate, neuroscientists are convinced that whatever happens in the mind arises from processes in the brain.

Such a deterministic viewpoint can make people nervous, Gazzaniga acknowledged. But even with deterministic brains, he said, individuals are able to come together and develop social rules of conduct. They are not zombies whose actions are determined solely by the neuromechanisms in their brains.

In a panel session on genes, proteins and disease, Vidal argued for the acceptance of a new term—"interactome"—that is gaining a foothold along side "genome" and "proteome." He and other researchers argue that human diseases might correspond to different states of very complex networks of macromolecular interactions—what they call interactomes. Changes in genes may be only indirectly correlated with such disease states, Vidal said.

Kathleen Merikangas, an epidemiologist at the National Institute of Mental Health, said environmental factors clearly influence the expression of disease in a person with a genetic predisposition. She mentioned the Pima Indians, who have only a 2 per cent prevalence of Type II diabetes when living an agrarian lifestyle in Mexico but a 50 per cent prevalence when they live a more sedentary lifestyle on a reservation in Arizona.

Understanding environmental influences could be even more important in the future, she said, than understanding the processes by which genes exert their influence.

In a session on sustainable development, ecologist Stuart Pimm of Duke University said Malthus's prediction of widespread famine due to population growth may come true over the long term, but the more immediate concern will be human aspirations for higher living standards. Pressures on the environment are driven by population, per capita wealth and the amount of goods produced, he said, and the dominant term in the equation is going to be consumption.

William Clark, a Harvard University ecologist, said the predicted doubling of the Earth's urban infrastructure over the next generation is an issue that has received very little attention but which threatens stresses just as real as climate change or energy shortages. It is a topic desperately in need of scientific study, he said.

Clark also made an impassioned plea for scientists to get out of their labs and do more to educate the public about the scientific way of looking at the world.

Donald Kennedy, editor-in-chief of Science, praised efforts by Gershenfeld and others to engage young people's interest in science. "That's the future of this association, that's the future of this magazine, and we better start paying serious attention to it," Kennedy said.

To read more coverage of Science's 125th Anniversary, go to our special anniversary page.

Earl Lane

12 July 2005