>Imagine the "pollution" caused by civilizations which are advanced enough to tinker with the fabric of spacetime, but not advanced enough to understand (or care about) the long-term consequences of that tinkering.
I once had, and never used, an idea that the consequence of using such technology was to accelerate dark energy, so that the more civilizations used FTL travel, the greater the energy requirements became. As if seafarers had to deal with the oceans expanding just a bit every time they were crossed.
I once had, and never used, an idea that the consequence of using such technology was to accelerate dark energy, so that the more civilizations used FTL travel, the greater the energy requirements became. As if seafarers had to deal with the oceans expanding just a bit every time they were crossed.