Astronomers have now discovered over 4,200 planets orbiting other stars. Ranging from inferno gas giants with temperatures as hot as stars to rocky terrestrial worlds residing in the habitable zone, the diversity of planets in our galaxy continues to offer surprises. Exoplanet science is now going through a paradigm shift, as we move from the era of discovery to the age of characterisation.

By peering into the atmosphere of an exoplanet, one can infer the conditions on these distant worlds. Over the last decade, astronomers have developed new techniques to measure exoplanet atmospheres in remarkable detail. In the near future, these same techniques may allow the detection of biosignatures in the atmospheres of planets light-years away.

Dr. Ryan MacDonald is a Research Associate at Cornell University's Carl Sagan Institute. He completed a PhD in Astronomy at the University of Cambridge, England, in 2019. At Cornell, Dr. MacDonald is developing new techniques to study exoplanet atmospheres in preparation for the upcoming launch of NASA's James Webb Space Telescope in 2021.

In this talk, Dr. MacDonald will explain the main techniques used to characterise exoplanet atmospheres. He will highlight recent cutting-edge discoveries and finally look ahead to the prospects for detecting alien life elsewhere in our galaxy.