His finalist year: 1996

His finalist project: Taking measurements to determine the rotation of the Milky Way Galaxy

What led to the project: Simon DeDeo was born and raised in London, where his American father worked in the advertising industry. He read and reread Stephen Hawking's A Brief History of Time, and by the time his family moved back to the U.S. when he was in high school, he was fascinated by the universe and how it worked. He started playing with a discharge tube in the basement of a Phillips Exeter Academy building in Exeter, N.H., where he had enrolled as a student, and wrote "a number of naive letters to physics departments asking about using their equipment," he says. Jay Kirsch of the Massachusetts Institute of Technology wrote back, and DeDeo spent two summers in Cambridge hanging out with other brainy youngsters, all trying "to live up to the image we have of 'the scientist'—dedicated but brash, humble but authoritative."

During his time there, he started studying diffuse interstellar gas (the material present in the vast, seemingly empty spaces between stars) using a rooftop radio dish. He took measurements of the 21-centimeter emission, a radio wavelength associated with neutral hydrogen, to study the differential rotation of the Milky Way. He entered his results in the 1996 Westinghouse Science Talent Search and was named a finalist.

The effect on his career: During the trip to Washington, D.C., "there was a great deal of hijinks," he says, including one night where half a dozen 17-year-olds attempted to get into Georgetown bars using someone's college ID. DeDeo went on to Harvard University to study astrophysics, graduating in 2000, then spent a year at the University of Cambridge in England studying mathematics. He entered a PhD program in astrophysics at Princeton University in 2001, where he set about trying to work with the enormous data sets that modern technology continually produces about the universe. "It took me time to figure out how I fit in to these large projects that define contemporary science, and I am still figuring that out," he says.

What he's doing now: DeDeo is currently a cosmologist at the Institute for the Physics and Mathematics of the Universe, an international research facility at The University of Tokyo. The institute is focused on pure science, "fundamental research goals in uncovering and testing the basic laws of nature," DeDeo says. "It's an exciting move by the university here, and it's inspiring to be a small part of it."

He spends his days "figuring out what the universe will let us know, and separating out accident from law." This is always complicated. "Cosmology is a strange branch of physics because you can only run the tape once," he says. "It takes a kind of statistical sophistication to take a data set and turn it into something that looks like a classical case of test-and-control samples. More often than not the problem is finding the problem."

Recently he decided to look at that same topic he studied in 1996 as a high school student, the 21-centimeter emission of neutral hydrogen, to see what it might reveal about structures far larger than the spiral arms of the Milky Way. He's excited to still be working on the same problems that captivated him years ago, this time pulling in concepts from subjects as diverse as biology and game theory. "That's what a lot of science looks like in the end: very interdisciplinary," he says. "You have these very difficult problems, much larger than a single train of thought, and you take anything you can from whoever you can to solve them."