It is a rare researcher who can fundamentally change our picture of our place in the universe. In the 16th century, Nicolaus Copernicus did it by arguing that Earth is just one planet among many revolving around the sun; in 1924, Edwin Hubble did it by showing that our galaxy is just one among many. This year DISCOVER honors David Charbonneau, a Harvard University astronomer whose research could soon lead to an equally stunning revelation: By studying alien worlds, he may find the first direct evidence of life beyond Earth, a sign that our living planet is—yet again—one among many.
Astronomers currently know of roughly 200 planets circling nearby stars, and more and more of these so-called exoplanets are discovered every year. Most of the newfound bodies are so strange that scientists have had to coin new terms, like “hot Jupiters” and “super-Earths,” to describe them. Playing the celestial detective, Charbonneau has systematically gone about investigating these impossible planets and uncovering their secrets. In 1999, he led the team that made the first observation of a transiting exoplanet—one that passes directly between its parent star and Earth. By examining how the planet blocks out some of the light from its star, Charbonneau can see what gases are present in the planet’s atmosphere. In 2001, Charbonneau and astronomer Tim Brown of the High Altitude Observatory in Boulder, Colorado, used this technique to “sniff” the atmosphere of a huge, broiling planet called HD 209458b, even though it is 150 light-years away—4 billion times as distant as the moon. Just a few months ago, Charbonneau’s team at Harvard made another breakthrough and created the first weather map of an exosolar planet. The forecast: hot and windy, same as yesterday, same as tomorrow.
Charbonneau’s personal journey to becoming a planet hunter began with his desire to be a marine biologist. Born to a physician and a geologist, Charbonneau was no stranger to science. As a teenager growing up in Ontario, he visited the tide pools at the Pacific Rim National Park in British Columbia during a family vacation and witnessed firsthand the wild diversity of life at the border of the sand and the sea. His dedication to biology gave way to a passion for physics when he encountered special relativity, quantum mechanics, and Stephen Hawking’s A Brief History of Time. Theoretical physics then led him to astronomy, a passion that now colors every part of his life (his daughters are named Stella and Aurora).
