Dr Ryan MacDonald
Exoplanet Astronomer 🪐 🔭 at the University of Michigan (NASA Sagan Fellow).
Incoming Lecturer at the University of St Andrews 🏴 (June 2025).
- Graduating soon and still looking for an astronomy research project for Sep 2025? 🔭 I'm offering a Masters by Research (MSc) project on #exoplanet atmospheres 🪐 at the University of St Andrews 🏴 Join us to work on modelling JWST spectra! 📜 Application details: www.st-andrews.ac.uk/physics-astr...
- Nice micro podcast by @npr.org Short Wave on the K2-18b controversy. www.npr.org/2025/05/05/1... #exoplanet 🔭
- The K2-18b saga deepens with a great new paper out today by @luiswel.bsky.social (arxiv.org/abs/2504.21788). Turns out hydrocarbons can explain K2-18b's new JWST MIRI spectrum *without* the need to invoke DMS or DMDS as biosignatures. Read on to find out more! 🧵 #Exoplanet 🔭🪐
- Nice to see this research note on K2-18b from @astrojake.bsky.social, which demonstrates that a flat line (i.e. no spectral features) is a good fit to the MIRI data. #exoplanet 🪐 🔭 arxiv.org/abs/2504.15916
- For an accessible summary of the scientific debate surrounding K2-18b's atmosphere, check out @startswithabang.bsky.social's new article: ⬇️
- The evidence for biosignatures on K2-18b is flimsy, at best Last week, Cambridge scientists announced the discovery of DMS and DMDS on K2-18b: what they call a "surefire biosignature." Now, cut through the hype and get to the truth. bigthink.com/starts-with-... #space #astronomy #science
- Professor Raymond Pierrehumbert from Oxford has an excellent thread below about the viability of DMS as a biosignature and plausible atmospheric structures for K2-18b. 🔭 #exoplanets 🧵
- About that new paper on K2-18b, which headlines with "Scientists hail ‘strongest evidence’ so far for life beyond our solar system," evidently prodded by a Cambridge U. press release. arxiv.org/pdf/2504.12267 . It's not actually any kind of evidence for life, and here I'll give my take on the paper.
