Bold claim: Rocky Worlds is pushing the boundaries of how we search for life beyond Earth, using a collaborative JWST and HST program to probe rocky exoplanets around M-dwarfs. But here’s where it gets controversial: can secondary eclipse measurements at 15 microns with MIRI truly reveal atmospheric evidence on these worlds, or are we chasing signals that are too subtle to interpret definitively?
Rocky Worlds’ Director’s Discretionary Time (DDT) Program, a joint effort between the James Webb Space Telescope (JWST) and the Hubble Space Telescope (HST), sits at the intersection of community-driven priorities and flagship capabilities. The program is designed around the top recommendations from the Working Group on Strategic Exoplanet Initiatives, which gathered input from the broader scientific community on strategic concepts for a 500-hour JWST exoplanet DDT allocation. In short, it translates collective expertise into a focused, high-impact observing plan.
The core goals are twofold. First, to hunt for atmospheric signatures on rocky exoplanets that orbit M-dwarfs by measuring their secondary eclipses at 15 microns, leveraging the Mid-Infrared Instrument (MIRI) on JWST. Second, to map and characterize the stellar ultraviolet (UV) environment that surrounds these planets, using HST data. Together, these tasks aim to illuminate how atmospheres form, persist, or fail around small, cool stars, and how their host stars might influence potential habitability.
For a detailed account, see the full Rocky Worlds Status Report dated December 2025 at STScI: Rocky Worlds Status Report 2 Dec 2025 (https://www.stsci.edu/files/live/sites/www/files/home/jwst/science-planning/user-committees/jwst-users-committee/_documents/jstuc-1225-rocky-worlds-espinoza.pdf).
Astrobiology enthusiasts, explorers, and science communicators alike are following this work closely. The project’s blend of mission assets, community guidance, and ambitious science goals makes it a compelling case study in how modern astronomy coordinates large teams to address profound questions about rocky planets beyond our solar system.
About the author and affiliations: Explorers Club Fellow and ex-NASA Space Station Payload Manager turned space biologist and journalist, with experience across field expeditions (Devon Island to Everest Base Camp) and skills in ASL and synesthetic storytelling. Follow updates at @keithcowing on Twitter for ongoing commentary and analysis on space science and exploration.
