original: Earth is the only place in the universe where life has been confirmed to exist.
simplifications: Earth is the only place in the universe where life is known to exist. Earth is the only planet where life has been found so far. Only Earth has confirmed life in the universe. Earth is the only place in the universe with confirmed life. Earth is the only place where life is confirmed. Earth is the only place where we know life exists. Earth is the only planet known where life exists. Earth is the only planet in the universe that is known to have life. In the whole universe,  life is confirmed  only on the Earth. Earth is the only place in the whole world where life has been confirmed to exist.