Earthlight Author:Arthur C. Clarke THE TIE THAT BINDS — The human race had been born on a unique world...a world loaded with mineral wealth, unmatched elsewhere in the solar system. This accident of fate gave a flying start to man's technology -- but it made man dependent on his home world. — What were the independent republics on Mars and Venus to do? United in a Federation, t... more »hey were still dependent on Earth for such essentials as mercury, lead, and uranium -- and modern technology could not survive without them.