Contemplating a universe of magnificent vastness has not been a recent affair. In the first century B.C., the Roman poet and philosopher Lucretius approached the question with cunning logic: "Let us assume for the moment that the universe is limited," he posed. "If a man advances so that he is at the very edge of the extreme boundary and hurls a swift spear, do you prefer that this spear, hurled with great force, go whither it was sent and fly far, or do you think that something can stop it and stand in its way?" For Lucretius and a few Greek thinkers before him, it was hard to imagine that an impenetrable cosmic barrier existed. It seemed ludicrous.
Marcia Bartusiak, The Day We Found the Universe












