AKAramis said:The point to atmosphere 1 versus 0 is wind, EDG. Wind makes a huge difference in rock formation.
As you pointed out*, Mars runs in the Trace range (Martian surface ranges 6-10 mBar, and 1013mBar=1Atm), and the wind is profound in the environment.
Actually, by the MT definitions, the breakpoint for very thin is 0.1Atm, about 10x that of mars' 0.01Atm. (MT Ref's page 22.)
Yeah, I'd rather replace the "Trace" label with "Tenuous". that goes from 0-0.1 atms (0 to 100 mbar) continuously rather than in discrete steps of 0.01 atm. Mars and Triton in our solar system are actually below the lowest listed "Trace" pressure in WBH - Mars is about 6-10 mbar as you said, (0.006-0.010 atm) and Triton is in the microbar range (below 0.01 atm). But they're still not vacuum.