I like better the version in which a civilization could colonize the entire galaxy in about 5 to 50 million years (with low-speed means of space travel): http:/

I like better the version in which a civilization could colonize the entire galaxy in about 5 to 50 million years (with low-speed means of space travel): http://www.scientificamerican.com/article.cfm?id=where-are-they&page=3 http://www.scientificamerican.com/article.cfm?id=where-are-t...