After Contact, the Peloran medical treatments cured our worst diseases, and gave us the long lives that are common now.  And in a very few cases, we stopped aging at all.  We became Ageless.  It took us some time to realize how important Ageless were.  At first, all we saw was the shiny new gravitic technologies that could bring us to the galaxy at large far faster and safer than the mere rockets we flew the year before.  At first.