A University of Oklahoma post-doctoral astrophysics researcher, Billy Quarles, has identified the possible compositions of the seven planets in the TRAPPIST-1 system. Using thousands of numerical simulations to identify the planets stable for millions of years, Quarles concluded that six of the seven planets are consistent with an Earth-like composition. The exception is TRAPPIST-1f, which has a mass of 25 percent water, suggesting that TRAPPIST-1e may be the best candidate for future habitability studies."The goal of exoplanetary astronomy is to find planets that are similar to Earth in composition and potentially habitable," said Quarles. "For thousands of years, astronomers have sought other worlds capable of sustaining life."