Joe Armstrong, of erlang fame, presented _The Mess We're In_ at Strange Loop 2014. Thirteen minutes in he begins some computation to compare the complexity in a single laptop computer with some astronomically large numbers from physics "because [he] used to be a physicist": youtube 13:03
This is combinatorial explosion.
Armstrong goes on in his talk to discuss fault tolerance, distributed systems, and concurrency, as one might expect from one of the co-creators of erlang. See history of erlang at wikipedia
For our story, we'll let Peter Alvaro pick up the chapter about distributed systems.