Our life planet data set is an N=1 so we are searching what we know. It is certainly possible life is found on non-Earth-like planets and isn't carbon-based, ho

Our life planet data set is an N=1 so we are searching what we know. It is certainly possible life is found on non-Earth-like planets and isn't carbon-based, however we don't have any examples so we don't know what to look for. The initial search is focusing on Earth-like planets because we know the signs of life in that case. As for Antarctica, that may true but there would still be life, maybe not humans, on Earth. The fossil record shows there was life before Antarctica existed.