Scientists now believe that the trace metal contaminants around ancient sun-like stars are "remnants of rocky, potentially water-bearing bodies that crashed into their mother stars." This finding increases the likelihood that other Earth-like planets exist in other solar systems, and dismisses the possibility that trace metals in the atmospheres of these stars came from space dust. "We've suspected for a few years that the interstellar medium was not the solution because there were some problems with it. This seems to be the final nail in the coffin," said astronomer Patrick Dufour.