Back in the early 1970s, Dava Sobel was a young writer known around Cornell for her interest in science -- and for the signature pink bicycle she rode between interviews and the Cornell Chronicle office. Now, she's a best-selling author, known around the world for her books "Longitude" and "Galileo's Daughter."

The pink bicycle is long gone. But Sobel's fascination with science and her fondness for Cornell remain.

Sobel, whose most recent book is "The Planets," visited Cornell (76.5 degrees west longitude) April 11 for a casual day of Mars exploration with astronomers Jim Bell, Steve Squyres and Rob Sullivan and for a stroll around the much-changed campus. In the evening she spoke to students at Alice Cook House about her career path, the obstacles (and the fun) along the way, her next project (a play about Copernicus) -- and about what it takes to make a seemingly esoteric branch of science (lines of longitude, for example) into a compelling story.

Sobel originally intended "Longitude" to be a magazine article, she told the audience. But as publisher after publisher rejected the idea as too boring or weird, that seemed a stretch. Even when her pitch was accepted as a book deal, it got a cool reception from friends and acquaintances.

"People would ask what I was writing about, and when I said 'longitude,' they would sort of look down," she said. "The topic was something that seemed not interesting. My son would ask me, 'Do you really think anyone will read this?' And I would say no -- but that we're working together on something I can be proud of. And it's not often in life that one gets to do that."

But when "Longitude" was published, people did read it -- in droves. "It turns out to have this history with a life and death drama," Sobel said. "Once you learned the story it made the world a more interesting place."

And stories with compelling human elements, she said, are more common than one might think -- even in fields commonly perceived as boring, esoteric or intimidating.

"If you want [the public] to read about science, you have to make it interesting," she said. "And I don't think it's that hard -- it is interesting."

From interesting to compelling, though, is a question of finding the human drama that even the nonscience-inclined can relate to. And that can mean slogging through tedious background work (Sobel spent months sifting through archives and translating letters as she researched "Galileo's Daughter") -- or stumbling into an unexpectedly rich and intriguing new world (as she did when she entered the world of the Poor Clares, the 800-year-old community of Catholic nuns with whom Galileo's daughter made her home).

As Sobel, who is fluent in Italian, set out to read and translate letters from Galileo's daughter, she knew the task would be tough and often unrewarding. But it was an early comment from one scholar that made her certain the story would make it worthwhile.

"He said to me, 'When you read those letters, they'll break your heart,'" she said. "So I knew it would be good."