Surface pressure on Mars is about 0.6 kPa, just 0.6% of Earth's, low enough that liquid water boils away while still freezing cold. The deeper the terraforming runs, the more the sky shifts from rusty brown to blue, the polar caps melt, shallow seas pool in the lowlands and greenery spreads over the continents. The solar wind then restates the root problem: the core has cooled, the dynamo is off, and with no global magnetic field the new atmosphere gets stripped away again.
Surface pressure on Mars is about 0.6 kPa, just 0.6% of Earth's, low enough that liquid water boils away while still freezing cold. The deeper the terraforming runs, the more the sky shifts from rusty brown to blue, the polar caps melt, shallow seas pool in the lowlands and greenery spreads over the continents. The solar wind then restates the root problem: the core has cooled, the dynamo is off, and with no global magnetic field the new atmosphere gets stripped away again.
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