Great piece thanks Ethan. However you’re article doesn’t seem to address the problem time travel technology speculation always fails to address. This is that we can apparently conclude that humanity will never ever develop time travel because no one from the future has actually turned up. And presumably they could have turned up, anywhere and anytime no matter how far into the future it may be that such technology was actually mastered; unless we are to conclude that ufos and ancient gods are in fact visitations from our own distant descendants? At least that theory solves the problems of intergalactic space travel I suppose. Actually, if you could time travel and facing a resource exhausted planet it was that or head off into the bleak barrens of space hoping for another habitable planet, well you probably would opt for a return to a pristine past on your own world. Hmm…