We left Terra as ghosts.
Leaving our bodies behind, we were slung forth. We left not from fear, not to escape a tragedy, not because of any sudden desperation; we were pushed by the more careful, sneaking unease which has always grown under the skin of humankind: the curiosity to know more. There were those among us who fled their pasts, certainly; but the voyage was in the name of discovery. At least, that is what we hoped for. Unknown adventure, wild magics, and stories to tell our children and their children.
As all civilizations are drawn to the night sky, they eventually find there an ancient unseen magic in the waves of black. Terrans, once they wove the baskets to capture the dark energies, were entranced by the massive power required for such a strange and unknowable spell, pulsing out in strange birth cycles from the heart of the galaxy. And so, we were the ghosts sent to meet the caster. Danger catches up to any mortals who chase the Oldest magic: let this be a warning, of a kind, to you who catch a glimpse of the black powers at work. The quest for understanding may change you far more than you desire to be changed.