Achievement

In the near future, space-based telescopes will record spectral features of Earth-like extrasolar planets that will be perhaps indicative of life (so-called biosignatures). In order to better design such a telescope, IGERT trainee Ty Robinson has used Earth as a template with NASA’s EPOXI mission, which has observed the full disk of Earth for an entire rotation on several separate days. By studying the daily variations in total reflected light from Earth, he has determined the positions of continents, clouds and oceans around the planet, as well as the variability of Earth’s weather systems. He also studies the distribution of vegetation on Earth by mapping the "red edge" in Earth’s spectrum, caused by an abrupt jump in how well plants reflect light at a wavelength of about 700 nm. EPOXI spectra of Earth’s atmosphere also have revealed both methane and oxygen, which are good indicators of life.