Our future is in the stars. If one understands what guides the stars, it is possible to see that humankind is approaching its relatively short existence in light of the age and scope of the universe.
This brings up my favorite theory (likely not a good choice of words) — probability balance. Meaning that stars are born and stars die, creation is always at some point in time offset by destruction. We humans live on a finite planet, limited by both space and resources. We have come a long way as a species over the last three hundred thousand years, and have gone exponential over the last several centuries regarding our acquired knowledge and our technological advancements.
Because, however, of the universal law of probability balance the seeds of our demise are cooked into our magnificent accomplishments, and so we are fast running up against our grand destructive offset. For coming in concert with our great positive technological advancements are the thousand of nuclear tipped missiles poised capable of ending humanity ten times over. And if that were not enough our activities have reach the stage were we are not so slowly cooking ourselves to death. Moreover, if even that were not enough to end our earthy domination, which most definitely it is, history shows that at some point a natural calamity must do us in.
The bottomline is that the old man with the sign saying that the end is near was not wrong, he just has had terrible timing. Humanity has had a great run, but the full force of the negative aspect of probability balance is about to play out against our preferred interests.