[Fedoranimus]

Where do you draw the line though? Planet Earth used to be a lot bigger than it is now (metaphorically speaking).

"All of which is happening in the Solar System..."

"All of which is happening in the Milky Way..."

"All of which is happening in the Observable Universe..."

It's probably a cycle that will occur as we make advances in communication technology.

[adrianN]

The speed of light puts a hard limit on places that can easily exchange ideas and customs. At the very latest when we leave the solar system there will be significant diversification.