Andrej K makes an interesting point and Autism Capital's dismissive reply is wrong.

It is rational to be more afraid of man than of nature, because it is rational to be afraid of powerful optimizers.

This is also often why we are more suspicious of for-profit versions than non-profit versions of the same activity.

It is rational to realize that our entire world/planet/solar system, as well as each individual human being, is inevitably and obviously mortal. And no amount of technology, flights into space, or extension of life span will change this fact. 

So all of your musings are nothing more than self-indulgence.