We never knew Earth.  We had been told stories about it and our schools tell us we are from there.  100,000 years ago we left Earth.  From what we are told we left because the planet could no longer sustain life.  The great star arks were built so that we could leave for the stars in search of a new home.  

Earth had pretty much been long forgotten.  That is until someone decided to look toward it in the sky one night.  It now shined sapphire blue again.  A beautiful pale blue dot seem to be calling us back home.  One star ark will leave for Earth in 2 years.  I have signed on to be one of its passengers.  To see where we came from.