How did Lucretius explain the formation of worlds?

In his didactic poem De rerum natura (On the Nature of Things), Lucretius explains the formation of worlds through the movement of atoms within an infinite void.1

According to his theory, all atoms would have moved downward through infinite space in a parallel, eternal stream, never colliding to form complex systems, had they not occasionally experienced an indeterminate "swerve" (a minimal deviation from their path). These random swerves caused atoms to collide and aggregate, leading to the creation of an infinite plurality of worlds.1

Lucretius posited that all things, including celestial bodies and the world itself, are ultimately systems of moving atoms separated by intervals of void. These systems cohere based on the shapes of the atoms involved, and all such structures are inherently perishable, subject to change through the addition, subtraction, or rearrangement of these changeless, irreducible particles. He emphasized that while these processes govern the universe, the gods did not create or manipulate the world, as they exist remotely from human affairs.1