Artist's representation of the Trappist-1 system with the exoplanets at scale between each other and the host red dwarf star. The ESI (Earth Similarity Indice) calculated by Abel Mendez (PHL) for each exoplanet is added. For comparison with our solar system planets, Earth's ESI is 1, Venus's ESI is 0.44, and Mars's ESI is 0.64. Caution: the ESI is not a direct measure of habitability but formally a fuzzy comparison, using a distance metric, between a selected set of planetary properties of a planet and Earth. See http://phl.upr.edu/projects/earth-similarity-index-esi for more information.