We’ve already talked – a bit – about the possible role air pressure might play in planetary colonisation. I didn’t do much more than dip my toe into what is by any standards a vast topic. You could loosely summarise it as ‘human beings function best at 1 standard atmosphere’ – surprise, surprise! However, there is also some flexibility – presumably, our pre-human ancestors did encounter big hills and mountains often enough for evolution to factor it in. Human settlements can and do exist at altitudes as high as ~5000 metres.
Gravity, however, is potentially a very different problem. It’s something that will be a fundamental property of any planet. It’s also something that isn’t amenable to human influence, short of some kind of completely-incomprehensible, borderline-magic type technology. But, irritatingly, it’s something that will have major health implications for any putative human society. So it can’t be ignored. One can imagine taking supplements to deal with chemical deficiencies in the local soil, one can imagine pressurised houses to deal with air pressure differences, one can imagine vaccines or perhaps genetic engineering to cope with local diseases – but you can’t really do anything about the surface gravity! (By the way, if you think I’m being absurdly glib in dismissing the other issues, you’re dead right! All of these would be major undertakings just by themselves…)
Now, a note before we go any further. Most of this series of articles will be me commiting the physicist’s cardinal error – speculating outside one’s own field! So, any errors you see in the medicine and the biology are most definitely not my sources’ fault, they are a consequence of my own faulty comprehension. (Incidentally, if we do have any biologists or doctors in the audience, I would be very interested in their views on this topic.)
First off, let’s start with a brief – and it will be brief! – overview of what gravity is from a physics perspective.