On: Mars likely to have enough oxygen to support life:...

[adrianN]

Neverending exponential growth is not possible through space colonization. We can grow at most as the surface area of a sphere that expands at the speed of light, realistically much slower.

[pferde → adrianN]

In sufficiently long term, it is not entirely correct, because colonized planets will eventually start sending out colonizers themselves.

[adrianN → pferde]

That doesn't work. They'll only reach places already colonized.