Comet Enthusiast

In the next few years, the number of catalogued exoplanets will be counted in the thousands. This will vastly expand the number of potentially habitable worlds and lead to a systematic assessment of their astrobiological potential.

A U.S./German research team proposes to rank planets on both an Earth Similarity Index (ESI) and also a broader Planetary Habitability Index (PHI). The first tier consists of an Earth Similarity Index (ESI), which allows worlds to be screened with regard to their similarity to Earth, the only known inhabited planet at this time.