the human body will encounter complications in low and zero gravity
ftl will never happen
space stations are a scam that rich tech ceo's promise
mars cannot be terraformed
life is probably unexceptional and we will never make contact with others
you will all die on earth
This is great stuff.
Ian Banks and many others have come to the same conclusion, that even with life extension interstellar imperialism is basically impossible at STL speeds. Even with FTL it is difficult, The Culture is certainly a (somewhat diverse) cultural union, but states proper don't exist and it's pretty much impossible to stop secession.
The Player of Games establishes that the (rather small) Empire they found is the second centralised interstellar state ever discovered in Galactic History (and Culture history alone goes back 6000 years). And it uses 99.9 percent of its resources keeping itself together
Karl Schroder does make one that exists by forcing people on the colonies into increasing amounts of cold sleep to sync travel times.