Continual miniaturisation allows resources to be conserved, efficiency to be increased, pollution to be reduced, and the remarkable flexibilities of the quantum world to be tapped. Very advanced civilizations elsewhere in the universe may have been force to follow the same technological path. Their nano-scale space probes, their atomic-scale machines and nano-computers, would be imperceptible to our course-grained surveys of the universe.... This may be the low-impact evolutionary path you need to follow in order to survive into the far, far future.

The Book of Universes: Exploring the Limits of the Cosmos (2011)