Broadening the Search for Life on Exoplanets
For the millennia humans have been looking to the heavens, the assumption has been made that we are right in the universe. Because we cannot see the curvature of the Earth, it must be flat. Because we do not feel ourselves moving, the stars and planets must be circling us. Because there is life on Earth, life must require an Earth-like home. These first two points have already been corrected and now this third one may soon be too.
Researchers at Washington State University are proposing a new system to categorize exoplanets, the planets found outside our solar system. The current system only considers how similar a planet is to Earth, and while the new design preserves this index, it also adds the Planetary Habitability Index (PHI). An explanation for why this new index is needed can be found orbiting Saturn; Titan. This moon is bathed in hydrocarbons, yet studies have found it may be habitable. Of course a human, and most other life on Earth, couldn’t survive there because we require water, but new kinds of life could develop for those conditions.
What the PHI would do is examine the chemistry we find on an exoplanet (believe it or not but we do have the ability to measure the chemistry of another planet’s atmosphere) to determine if it could support any kind of life. With the possibility of thousands of new exoplanets being found in the coming years, the use of this index could not be more apparent.