Dr. Ryan J. MacDonald

I am a Lecturer in Extrasolar Planets at the University of St Andrews in Scotland. My research merges observational astronomy and theoretical astrophysics to reveal the atmospheric composition and nature of planets orbiting other stars. I lead several programs using the James Webb Space Telescope (JWST) to characterise exoplanet atmospheres.

From 2022-2025, I was a NASA Sagan Fellow at the University of Michigan. At UMich, I analysed the first exoplanet spectra from JWST through several international initiatives. We detected new molecules in the atmospheres of giant exoplanets and conducted the first search for atmospheres on rocky planets around other stars. See my research highlights.

From 2019-2022, I was a Research Associate at Cornell University’s Carl Sagan Institute. My Cornell research covered many areas, such as the impact of 3D effects on exoplanet spectra and the detectability of biosignatures.

I completed a PhD in Astronomy at the University of Cambridge in 2019. My PhD research focused on deriving the chemical composition, temperature structure, and cloud properties of exoplanets - ranging from inferno gas giants to Neptune-mass worlds. These same techniques will soon enable astronomers to seek indirect signs of biological activity on habitable rocky planets, thereby answering one of the most profound questions about our place in the Universe.

Before my PhD, I completed a Master’s Degree in Physics at Oxford University. Whilst there, I investigated designs of thermal-Infrared instruments for a proposed European Space Agency (ESA) sample return mission to the moons of Mars. I also served as a data analyst during the later stages of ESA’s Venus Express mission.

Alongside research, I am an active science communicator and strong advocate for widening involvement in STEM education and research. In addition to radio, TV, and podcast interviews, I have been a freelance popular science writer, YouTube creator, and a public speaker in schools, astronomical societies, and science fairs.