When Sara Seager was growing up, Earth and its eight siblings were the only known planets in the universe. Other worlds existed only in science fiction, and the prospect of finding life on another planet seemed like a remote dream.
But that dream has edged closer to reality, thanks to Seager (BSc 1994). A planetary scientist at the Massachusetts Institute of Technology, she is examining some of the 200-plus planets that have been discovered orbiting distant stars. Seager, 35, has devised a way to assess the atmospheres of these faraway planets – a crucial step in determining whether they can support life. At the same time, she is helping with instrument design for NASA’s Terrestrial Planet Finder, a space-based observatory that likely will be launched in the next 15 years.
So far, almost all of the known extrasolar planets are more like Jupiter than Earth – gas giants inhospitable to life. The real prize will go to whoever discovers a world similar to our own blue-green orb – rocky, temperate and with an atmosphere containing water, carbon dioxide and ozone. Seager expects one to be found in her lifetime. “Every single day I wonder if there is life on another planet,” she says. “And I wonder what kind of life it might be.”