Abstract Last May, NASA launched a spacecraft with a curious fillip: a greeting card to wahtever creatures may be inhabiting the Earth some eight million or more years in the future. The satellite builders at Bendix Corporation and NASA believe it will not be braked by the atmosphere for at least eight million years. They realized that here was a unique opportunity to communicate wiht the future. Dr. Carl Sagan of Cornell University designed a stainless-steel plate carrying a message that was...