Modern day scenario:
Let's say that right now on this very day, astronomers discover a comet or asteroid on a collision course with Earth due to impact in 2036. Let's
say that it's large enough to cause an extinction level event. Let's say that we've tried everything we can think of to keep this object from
hitting us, but are unable to change it's course. In a last ditch effort to minimize the damage, the world's nuclear powers come together and launch
our entire arsenal at this thing. The hope is that we break it into pieces small enough to burn up in our atmosphere, but the result instead winds up
being more widespread damage.
What would our options be to insure that mankind lives to see another day? Would there be no escape? None whatsoever?
I can only think of 2 possible ways to escape certain death:
1. Build massive bunkers deep below the Earth's surface capable of sustaining life for many, many years.
2. Build space stations capable of sustaining life for many, many years.
Now given our ever so strong survival instincts, I can assure you that both of these measures will indeed be taken, even in the absence of a plan on
where to go from there. Of course the super rich and all of their friends will be the ones locked in the bunkers and flying into space, and they will
take all of our currently suppressed technology with them. For those in space, this technology will include the cure for aging. Think about where
cloning, stem-cell, gene, and nano technologies are headed, and you'll realize that this really isn't far-fetched at all.
The rest of us will be left to fend for ourselves and I don't think I need to tell you how that's gonna turn out
So the fragmented impact happens and it generates enough heat to completely destroy everything that took us thousands of years to build, without a
trace. All above ground life is gone and the Earth becomes "uninhabitable" for thousands of years.
At some point, earthquakes and famine will compromise the underground bunkers, forcing their inhabitants to return to the surface before the Earth is
ready. The seed banks will be utilized to restart vegetation and DNA banks will be utilized to restart animal life, but the atmosphere has changed and
nothing turns out the way it was before the event. Inbreeding and environmental changes lead to mutations and eventually mankind is no longer
comparable to his brothers still living in space. Due to either a lack of wood or a lesson learned from the impact, the majority of new structures are
built from stone.
Generations pass, religions are reborn, wars ensue, and our true history is destroyed and rewritten by the victors.
Those living in space have the added benefit of a controlled environment. The cure for aging has shortened the learning curve and technology advances
rapidly, but the lack of bacteria and other necessary nutrients has rendered them incapable of surviving in an organic environment. Their ability to
reproduce naturally was lost in the process of curing aging, so the only way to increase there numbers is to produce clones. This leads to a mundane
existence and they eventually start a hybrid program with there mutated brothers on Earth because they can't find life anywhere else in our solar
system. Also, Einstein was right and light speed is impossible, so searching outside our solar system for life would take millions of years.
So there ya go. That's my condensed version with lots of holes in it, and I get a little screwy with my use of past/present/future tenses, but I
think you should get the idea of what I'm saying. Imagine what we'll be able to do 100 years from now, and who's to say this hasn't already
happened before. Maybe even many times over.