Gregory Benford 
Against Infinity 
Jupiter Project Book 2

On the poisonous, icy surface of Ganymede, a man and a boy are on a deadly hunt. Their prey is the Aleph — an unknowable alien artifact that roamed and ruled Ganymede for countless millennia. Indescribable, infinitely dangerous, the Aleph haunts men’s dreams and destroys all efforts to terraform Ganymede into a habitable planet. Now in a modern world ancient struggle is joined, as a boy seeks manhood, a man seeks enlightenment, and a society seeks the power to rule the universe.