On this same note, insulation in general. We can only make something so strong, conductive, refractory, light or hard, so we’ve internalised the expectation that there’s always practical limits. But insulative? There just isn’t one. That means that with an arbitrarily small source of energy - body heat is not only possible but typical - you can overcome unlimited external coldness. We’ve being doing this since before we were human, by many definitions.
On this same note, insulation in general. We can only make something so strong, conductive, refractory, light or hard, so we’ve internalised the expectation that there’s always practical limits. But insulative? There just isn’t one. That means that with an arbitrarily small source of energy - body heat is not only possible but typical - you can overcome unlimited external coldness. We’ve being doing this since before we were human, by many definitions.