Wouldn't a self sustaining underwater colony protect us from all but the worst asteroid impacts? If you go even 100m down surely you would be protected from pretty much everything but the earthquakes?
Depends on the size and location of the event just like land. Being underwater didn't protect the water based dinosaurs from the impact that ended the dinosaur's reign over the earth.
It would have been the biosphere collapsing, that killed off the water based dinosaurs. But if our hypothetical colony was self sustaining (perhaps as some sort of precursor to space colonies) it should be ok.
Well, you could use geothermal energy or make use of the temperature gradient between the top of the ocean and the 100m down.
Its true the that pressure difference between vacuum and sea level is much greater than between sea level and deep underwater. However you have the advantage of not having to lift everything up to orbit. You you can build a really heavy steel tank using relatively 'simple' construction techniques, then just tow it out to position, before sinking it and anchoring it to the seabed.
The more I think about it, the more it sounds like like a self-sustaining undersea colony would be a affordable and useful way both ensure species Survivability and act as a prototype for a space colony.
How so ? Neither water-based, nor land-based dinosaurs are actually extinct. They've (mostly) shrunk a lot, yes, but that's about it. Location and size protected both kinds of dinosaurs, land-based or sea-based.
All birds are dinosaurs (in the same sense that humans are apes). Hell, you've probably eaten a dinosaur egg this week. And the water-based dinosaur descendants are very well known and the inspiration for how dinosaurs now look in musea, the crocodiles, when we're not actually sure whether crocs or chickens looked more like land based dinosaurs.
Large animals go extinct on a regular basis. The reason animals become big is for efficiency, and so often a prelude to extinction (of that particular branch). A rat is much more efficient (work/energy) than an insect. A cat is (a lot) more efficient than a rat or a mouse. Cows and other large mammals are unbeatable when it comes to the amount of energy a kilogram of cow tissue requires to stay alive. But there's usually a reason animals become efficient, and that reason is that their methods of gathering energy are actually becoming unusable, and so energy available to the species is lowering. So the species reduces in numbers, and the physical size of individuals grows. Increased efficiency only happens out of necessity, and if it can't turn the tide, the next step is extinction ... And yes, humans definitely count as large animals. I wonder if we're an exception.
Theoretically if said base could hover above the surface of the sea-bed during an earthquake scenario, perhaps it could resist most of the damage, provided it could remain stable.
Hmmm, perhaps if it was sort of tethered to the ocean floor using cables? Using a tethered base would also allow you to build in shallower water, as the flexibility would allow you to withstand some of the effects of a tsunami.
One of the biggest points of the article was that Mercury has abundant available energy from the sun - just stick up some solar panels, or the thermal gradients are perfect for running turbines - large enough to supply a lot of power, but not so large that engineering becomes hard. While there are some energy sources available underwater, it would seem to be much more difficult to exploit them.
or the thermal gradients are perfect for running turbines
They're completely useless, actually: they're in insulating rock with no ability to conduct away heat. As soon you try to exploit a temperature gradient, you destroy it.
