What led to your interest in astronomy?
My great aunt, Ruth Foster, nurtured my interest in science as a young child and took me to the planetaria in New York and Philadelphia. I loved stepping on the scales at the old Hayden Planetarium to see how much I would weigh on Jupiter and Mars, and there was a fantastic orrery in the ornate lobby showing the relative positions of all the planets.
My aunt also gave me wonderful books on astronomy by Isaac Asimov, Walter Sullivan, Tim Ferris, and others. Later in high school, Carl Sagan's "Cosmos" series on PBS convinced me that I wanted to study astronomy in college. It was my major at MIT.
Did you have a telescope as a kid?
Actually, no. I always just used my eyes and, on occasion, binoculars. I grew up in northern Vermont, so it wasn't unusual for us to see the aurora borealis. And the skies were wonderfully clear, especially in the winter. I did a lot of lying in the grass or snow at night, watching for random meteors, and letting my imagination run wild. Orion (one letter different from my last name) was and still is my favorite place to stare.
What drew you to this story in particular?
I worked as a public relations officer and the campus science writer at UC Santa Cruz for many years and got to know several of the astronomers involved with the planet-hunting project from the early days. It's been fantastic to see the number of planets outside our solar system go from zero a little more than a decade ago to 200 today. These discoveries were made by real people with the technical acumen to design such delicate instruments from scratch. They can watch stars moving toward or away from us at the speed that you and I walk or jog down the street. It's a remarkable feat, so describing it for a general audience was a great and fun challenge.
Was it moving to be in the observatory looking up at the stars?
I've been to many observatories, so I no longer have that raw feeling of awe about the sky and the telescopes we have devised to peer into its depths. What's more fascinating now are the guts of the observing instruments—the precise way that astronomers can parse starlight, and the often-cramped spaces within which the instruments must fit. It's optical wizardry under very demanding conditions. But the astronomers themselves do describe the big observatories as cathedrals, and inside the vast dark dome, it's easy to understand why.
Why is this work so important, when it doesn't have any immediate or practical implications? If you were trying to get funding for McCarthy and his colleagues, how would you argue for it?
I doubt we'll ever see a "practical" application for finding other planets, at least not until we develop a warp drive to visit them. Rather, we're simply trying to find objects such as the one upon which we live. We know an awful lot about the big and bright things in the sky and precious little about the fleeting and faint things. For the first time in human history, we can anticipate learning that other worlds with properties similar to ours exist. Whether life also exists on those bodies is a much more difficult question—and one that may take decades to answer. But simply finding them will show us whether our own cozy system of planets—with or without Pluto—is common or a fluke. It's the next step in our atlas of the universe. Geoffrey Marcy told me that his team gets letters from kids in 7th grade who have read about their project. They're asking questions and just starting to think about their place in the universe. That's incredibly satisfying for him, and he said, "When I think about my own mortality, about what I will do in my brief little flicker as a living human being on this planet, I would dearly love to contribute something. Finding the next generation of planets will satisfy that drive. This is what we're going to do with our lives."
Of course we can't know either way, but do you think there could be life on any of these planets?
No astronomer or science journalist would venture to say that any of the planets detected so far are suitable for life. We haven't yet found smaller solid planets where warm seas might flow. But we have weak imaginations when it comes to envisioning the forms that life might assume elsewhere. It's something we all hope to write about in a way that's based on science, not science fiction or mythology.
Was there anything funny when you were visiting the observatory?
Scientists like to cut out little non-sequitur headlines and tape them around the rooms where they work. On one old instrument panel from the late 1950s, I noticed a yellowed newspaper headline: "Don't Mess Around with Black Holes."
What was the most surprising thing you learned from this story?
Marcy and his colleagues have scores of other potential planets in the pipeline. But in most cases it takes years of data to be sure that it's a real orbital signature of a planet and not something else. They truly are perfectionists, and in 10+ years, they've never had to retract a planetary claim.