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Listen or download interview (mp3, 32 minutes, 30MB)
It’s a simple question, really: are there planets around other stars? Yet when astronomer Geoffrey Marcy posed it over 20 years ago, most of the scientific community thought it was impossible to answer. Finding other worlds like our own challenged the best technology at the time. Because stars are so bright and planets so comparably small and dim, even the largest telescopes could not directly distinguish a planet in the glare of its sun.
Marcy developed a technique to indirectly detect planets instead. As a planet orbits, it tugs gravitationally on its star, causing a tiny wobble. The wobble shifts the star’s light, and the size of that shift can tell a planet-hunter how large the planet is and how closely it circles its sun. By measuring changes in starlight over time—and refining his technique for over a decade—Marcy became one of the first humans to spot planets beyond our solar system and prove their existence. He has since discovered more extrasolar planets than anyone else. Marcy now leads the search for Earth-like planets and life elsewhere in the universe. He is a professor of astronomy at the University of California at Berkeley, and was elected to the National Academy of Sciences in 2002.
Marcy describes his quiet childhood in 1960s southern California, his household’s place in the women’s and civil rights movements, and the rickety telescope that sparked his curiosity about planets and the universe. Inspired by the beauty he glimpsed through its 4-inch lens and “nudged” by his aerospace engineer father to excel in science, he grapples with physics and astronomy in college and graduate school. In a fit of despair over problems with his postdoctoral research, Marcy decides to pursue a question that interests him personally but lies far outside the mainstream of mid-1980s astronomy research: is it possible to find planets around other suns?
His pursuit lasts 12 years and “embarrasses” many of his colleagues, he says, but it ultimately leads to success and fame when he and his longtime collaborator, Paul Butler, confirm the discovery of the first extrasolar planet in 1995. Marcy details the technical challenges of planet-hunting and candidly discusses his views on intelligent life elsewhere in our galaxy. He advises young would-be scientists to think carefully about their reasons for going into the field, and shares his surprising conviction that—despite his accomplishments—he should have quit science earlier in life.
Last Updated: 07-19-2004
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The audio files linked above are part of the National Academy of Sciences InterViews series. Opinions and statements included in these audio files are those of the interviewee and do not necessarily reflect the views of the National Academy of Sciences.