(February 18, 2019 at 10:42 am)Anomalocaris Wrote:(February 18, 2019 at 8:28 am)onlinebiker Wrote: Mars has virtually no magnehtic field.
Without a magnetic field, solar winds will strip away any atmosphere we try to build up on the planet.
So any colony will be a strictly artificial construct and less viable than one on our moon - by simple proximity.
Solar wind is inefficient in stripping atmospheric gases with heavier atomic and molecular weights, such as nitrogen and oxygen, or carbon dioxide. This is why mars still has a tenuous atmophere 3.8-4 billion years after last signs of any global magnetic field.
The length of time required to strip sizeable fractions an artificial Martian atmophere of 1 atmopheric pressure would on the order of tens to hundreds of millions of years.
In other words, even extremely pessimistic estimate of efficiency of mars terraforming still see us replenishing the Martian atmophere thousands to tens of thousands of times faster than solar wind can strip it away. So if we take 100 centuries to give mars a shirtsleeve atmophere, that atmophere should stay for millions of years before it would need replenishing, provided solar wind is the only thing eroding it.
(February 18, 2019 at 8:21 am)Gawdzilla Sama Wrote: You don't have to terraform the entire planet to get a shirtsleeve environment. I've proposed covering a side canyon of Marinis Vallenaris to make a biosphere suitable for humans. It would be a major engineering job, but not impossible.
It would then require a large technological and industrial base to support and maintain it. That base can not exist independently without continuous raw or proceeded material impor from earth simply critical mineral resources required likely do not exist on mars. So no isolation leading to biological speciation is likely to occur.
I didn't say it would be easy, or quick. But starting with smaller domes in a side valley for farming, and living in the cliffs, for protection from solar storms, etc., is the way I would go. Martian sand would make glass panels for the domes.