About the data
How We Identify the Top Potentially Habitable Exoplanets
At BetterThanEarth.com, we aim to highlight the most promising known exoplanets that could — in theory — support liquid water and perhaps even life as we understand it. To do this fairly and accurately, we combine two of the most respected public sources in exoplanet science:
- NASA Exoplanet Archive --The official NASA repository for confirmed exoplanets (maintained by the California Institute of Technology). We use the latest confirmed physical parameters — such as planet radius, mass, density, equilibrium temperature, orbital distance, and stellar flux (how much starlight the planet receives) — directly from their Planetary Systems Composite Parameters table (PSCompPars). This gives us the most up-to-date, peer-reviewed measurements available.
- Habitable Worlds Catalog (HWC) -- Created and maintained by the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo (PHL @ UPR Arecibo). The HWC is one of the leading expert classifications of potentially habitable worlds. It divides candidates into conservative (more likely rocky planets in the strict habitable zone where liquid water can stably exist on the surface) and optimistic (broader habitable zone, including possible water worlds or planets with thicker atmospheres). We heavily reference their rankings, Earth Similarity Index (ESI) values, and habitability assessments.
Our Approach
We cross-reference and combine data from both sources to build a balanced, evidence-based list:
- We start with the conservative and optimistic samples from the Habitable Worlds Catalog as our foundation — these represent the scientific community's most carefully vetted potentially habitable worlds.
- We then pull the most recent measured or calculated parameters (radius, mass, density, insolation, etc.) from the NASA Exoplanet Archive to confirm and refine each candidate.
- We prioritize planets that appear in both sources, score highly on the Earth Similarity Index (ESI), fall in the conservative habitable zone, show rocky or water-rich characteristics (when density data exists), and have favorable conditions for future observation (e.g., nearby stars or transiting planets suitable for telescopes like JWST).
- We apply additional filters such as low stellar activity (to reduce the risk of atmosphere loss) and stable orbits.
Important Notes
- All data is publicly available and credited to its original sources.
- No planet has been confirmed to be habitable — these are scientifically promising candidates only. However, we intend to keep the data as fresh as possible from multiple data sources.
- Rankings and assessments evolve quickly as new observations (especially from the James Webb Space Telescope) and updated catalogs become available. Our list reflects the best information as of early 2026.
- We are not affiliated with NASA or PHL @ UPR Arecibo; we are an independent enthusiast project synthesizing publicly available research for educational and inspirational purposes.
Data Sources & Credits
- NASA Exoplanet Archive: https://exoplanetarchive.ipac.caltech.edu
- Habitable Worlds Catalog (PHL @ UPR Arecibo): https://phl.upr.edu/hwc
- Additional context from peer-reviewed papers, JWST early results, and community discussions.
We believe transparency is essential when talking about the search for other Earths. Thank you for exploring these incredible worlds with us!