Re: Subtitle error -25 tons per square meter
The Earth's atmospheric pressure is around 10 tonnes (actually 100kN) per square metre. That is the pressure required to create the density we're used to at the surface.
So what would it be on Mars? Answer: still 10 tonnes per square metre. Think of it like this: if you take a pressure vessel and fill it with air at the Earth's surface, and then move it to orbit, the pressure is still going to be 10t/sqM. The only function of the Earth's gravity is to oppose the pressure in the atmosphere which has no containment vessel. But the pressure is created by the motion of the air molecules, not by gravity.
Concrete has a density of roughly 3t/cubic M but on Mars the gravitational force on it will be only around 1.1t. That would imply a dome thickness of 9M to create a dome which had zero tensile loading, but that really would be silly. As you wouldn't be able to see out of it, unless you can also make 12M thick glass windows, tunnelling would make far more sense.
I wonder how many people would volunteer to become one of Mar's new troglodyte underlords?