Science Forums 2

[CraigD]

Originally Posted by Thunderbird

It would be like pouring water into a leaky bucket.

Yes, but a planet-size, slowly leaking bucket. Best current data and theory suggest that in its distant past (the Noachian era, 3.8 to 3.5 billion years ago), Mars had significant amounts of liquid water, for on the order of 100 million years.

Again, the conventional goal of terraforming is not making an Earth-like world that will last long enough to recreate billions of years of terrestrial biological evolution, but to make other planets and moons human habitable for periods of time long by human standards – thousands, not hundreds of millions of years.