To all intents and purposes, it has. Which makes me wonder what Mars would have looked like it in its ancient shape, flush with water and a thicker atmosphere. If it still looked like that today, I have no doubt that humankind would already have tried to colonize and terraform it, or at least begun those attempts. Our urge to expand and explore have met no boundaries, not even that of space. So I suspect a more tempting planet in the nearby firmament would have long since been colonized.
- Solar Tilt and Biogeomorphism
- ‘Island-Hopping’ to the Stars