First and foremost, I will state that I am supposing that the creation of habitable environments on the large and small scale are achievable and that the human species will desire and succeed to achieve this. That is, we currently are not able to spread our species out amongst the stars, primarily due to the fact that we are currently unable to meet the challenges of long-duration interstellar travel. There are three limiting factors to man's ability to extend out into the universe and they are: time, technology, and physiology. In regards to time, human expansion into the universe is particularly limited currently. Outer space is huge. Colossally huge. I'd suggest that it is indeed the biggest thing possible. And in addition, space is for the most part completely empty. And I don't mean that there isn't discernible matter, but that those quantities of matter over the microscopic level, are quite few and far between. People don't even ...