Stars in her eyes.

• Author: Postrel, Virginia

Astronomer Sallie Baliunas on sunspots, global warming, and the benefits of privately funded science

Interviewed by Virginia Postrel and Steven Postrel

When she became an astronomer, Sallie Baliunas (baliunas@cfa.harvard.edu) never thought she'd be posing for magazine photos. But her life as a scientist hasn't been a matter of pure research. In her quest to study the stars, she has found herself drawn into the world of entrepreneurship and public policy.

An astronomer at the Harvard-Smithsonian Center for Astrophysics in Massachusetts, Baliunas is also the deputy director of the Mount Wilson Institute in the San Gabriel Mountains north of Pasadena, California. She spends about a week a month on the West Coast, using Mount Wilson's historic 100-inch telescope to study "sun-like stars." Baliunas came to the observatory as a graduate student in 1977. On her very first night, a lightning bolt struck a tree outside the dining room. "All the windows in the building were shattered from the shock wave of the tree disintegrating," she recalls. "This was an omen whose meaning was not clear until years later."

The observatory where modern astronomy was born would go through similar shocks in the years to come, as its owners turned their attention elsewhere. But for the dedication of a handful of technical staffers and astronomers, Baliunas among them, Mount Wilson would have been essentially abandoned. Instead, the observatory has not only a new tease on life but some of the best observational equipment in the world. The reborn facility is demonstrating how private funding and advanced technology can nurture innovative science.

Baliunas's own work benefited from Mount Wilson's years of neglect. Telescope time is rare, and few astronomers have the luxury of studying the same stars night after night, year after year. She's the first to admit that her research "could only have been done at an essentially 'abandoned' facility, where the competition for telescope time had disappeared." Baliunas is returning the favor, working without pay to raise funds, improve equipment, and manage the operations so such long-term research can continue. She never expected to be a manager but, she says, "The choice seemed clear: either grow the observatory or lose the research program."

In between observing and management, Baliunas can also be found testifying before congressional committees and giving papers at conferences on global climate change - a subject she was drawn to by her research on the sun's fluctuating magnetic field. She is a leading greenhouse skeptic. How, she wondered, could climate models be so specific when we hardly understand the sun or its effect on the earth? Baliunas talked about this and other questions with REASON Editor Virginia Posttel and her husband, Steven Postret, an economist who teaches business strategy at U.C.-Irvine, under the Mount Wilson dome in late June.

Reason: What do you study?

Sallie Batiunas: I'm interested in why the sun has a regular cycle of magnetism. There's a clock, so to speak. Sunspots come and go every 11 years, and the sun's energy output changes in step with those changes in magnetism. The sun also changes on longer time scales. That has an influence on the earth's environment. So the question is, Why does the sun do that? There is no good basic theory that says why the sun would have a magnetic clock.

Reason: So you look at other stars to try to figure out what's going on with the sun?

Baliunas: Right. Here's an analogy. You're an extraterrestrial and you come to Earth, and you have 24 hours and you want to study the life cycle of a human. You can do one of two things. You can sit and follow one human for 24 hours and watch tiny microscopic changes in that human, or you can gather together a whole town and take information and look at the commonality. You can say, here's an infant and he needs to be taken care of, and here's a kid, and here's a young adult, and put together a picture of the human life span that way. I look at what I call "sun-like stars" at different phases of long-term evolution. It's a great deal quicker than waiting around for the sun to do something.

Reason: Have you gotten any interesting results?

Baliunas: My mentor here - who is buried outside the dome, Olin Wilson - asked the question, Is the sun's 11-year cycle common on other stars, or is it something peculiar about the sun? He began a program here at the telescope in 1966 to follow 100 stars, month after month, year after year. When he retired, I came aboard, and now we have over three decades of records. We see at first glance, what the sun does is not unique. It's a universal trait.

Reason: Eleven years?

Baliunas: Eleven years, on average, if the stars are as old as the sun is. Age seems to make a big difference. When the sun was younger and life was forming on Earth - the sun was about a billion years old, about 3.5 billion years ago - the sun was spinning several times faster than today. That meant that the dynamo that powers the surface magnetism was working much more efficiently, and so the magnetism was much higher. There were more sunspots, there were more high-energy particles, there was more variability of ultraviolet and X-rays.

Reason: How would that affect conditions on the earth?

Baliunas: In several ways. One way is, with that higher amount of activity, there's much more X-ray and ultraviolet flux. The X-ray flux would be about 100 times larger than today. That energy certainly has biological effects - effects on DNA; it can even kill cells. So the environment was much more dangerous to life than today. The ultraviolet fluxes would also be larger, maybe 10 times larger. In addition, the changes over time scales of years or so would also be much larger. So not only are they at a higher sustained level, but they vary, and the variations are larger. The total energy of the sun would have been varying by several percent over a time scale of a few years, during the sunspot cycle. That would play havoc with the climate.

Reason: You've been writing some papers suggesting that terrestrial climate today may be affected by solar variations. In fact you've suggested that some of the warming that people have attributed to burning fossil fuels may actually be the result of natural fluctuation. How did you get involved in that?

Baliunas: Nearly 15 years ago, I started hearing that there now were models - simulations - of the earth's climate system that could be projected 100 years into the future. I was curious and thought, "Wow, that's a significant leap in meteorology and climatology. I want to learn about that." So I began looking at the models and how they can make predictions so far in advance. I also began to look at climate simulations run on computers and ask the question, What is the natural level of climate change? What is the influence of the sun?

The reason for asking how the sun might influence it is that there is lots of direct evidence that the sun has an impact. For example, the sun changes in its brightness [an average of] every 11 years with the magnetic cycle. We know that from recent satellite measurements. But going back further in time, we know the sun changes every few centuries. During the 17th century, which was an unusually cold period on Earth, the sun had very little magnetic activity for about a century - the Maunder Minimum, coincident with the Little Ice Age.

Reason: What is the Maunder Minimum?

Baliunas: The Maunder Minimum is this episode in the 17th century where the 11-year cycle was suppressed - was very quiet - and the sun dropped to very low levels of magnetism.

Reason: The 11-year cycle disappeared?

Baliunas: Almost. There were certainly long months of time, and even a decade toward the end of the 17th century, when sighting a sunspot was very rare.

Reason: Is there any theory for what caused that?

Baliunas: That's the hot question. We have to explain the 11-year cycle in the first place. There's a crude picture that says we know the sun's magnetism changes with time because of the way the sun spins and the way the outer layer rolls with convection. Beyond that, it's not a good theory. Making an 11-year repeating cycle is difficult in most theories. Making it disappear every...