> Another thought is the fact that no advanced civilisation has ever made it to earth is proof that any intelligent species is destined to destroy itself before

> Another thought is the fact that no advanced civilisation has ever made it to earth is proof that any intelligent species is destined to destroy itself before it can evolve far enough to travel the stars. Looking like our planet might prove this one to be pretty close to accurate at least in our case, within the next hundred years or so. If not from nuclear war then from running extremely low of key resources on the planet and suffering a massive conventional war over the remaining resources. Freshwater alone seems like it can cause it. We already have major cities almost entirely running out of fresh water (see Mexico City this year). Western US came worrying close with Lake Mead's water level a couple years ago too, but thankfully it eventually started raining enough to replenish it again.