posted on Dec, 4 2008 @ 04:26 AM
Both points are pretty much baseless speculation. So since we're speculating...
Firstly, just because it took human level intelligence this long to evolve on Earth, doesn't mean that similar levels of intelligence could not
develop sooner on other planets - or later, but on planets that orbit around stars which much greater lifespans than Earth's. Indeed, while there's
absolutely nothing to support this claim - there's really nothing to indicate that human-level intelligence could not even have evolved long ago in
Earth's history.
Note: Human level intelligence does not mean human level of technology or society - only intelligence levels. Of which we have several species of
currently extinct hominid which suggest that a roughly human level of intelligence was around long before modern humans.
Also note: Our sun is only half-way through it's estimated life cycle, and has about a billion years left before it starts to exhaust it's fuel
supply and burn hotter - slowly making this planet uninhabitable to life as we know it. Humans have only been around for an estimated 200,000 years
and most of our technological progress has been made in only the last few hundred years. In a few hundred more years, and certainly within the next
few millenia, we'll have the capability for extra-planetary travel into space reliably. If this happens, then when the sun does die, it will not mean
the end of our species. Only the end of our original homeworld. (However, by then, I would suspect that our continual merger with technology will have
advanced us beyond merely "human" by that point)
Secondly: I don't think humanity has the capability of rendering this planet uninhabitable to all but bacterial live via climate change. That's a
silly supposition. This Earth has seen many cataclysms far more devastating than humanity. For instance, the 10-mile wide asteroid impact which
heralded the extinction of the dinosaurs did more damage to this planet than all of the damage humanity has dealt it in our 200,000 year history
combined - and thensome. Not to mention it happened in a much, much shorter time frame. Even all of our nuclear stockpiles combined could not even
come close to matching the destructive power of that asteroid. Yet here we are a paltry 65 million years later.
This extinction level event wasn't even the worst or most cataclysmic in Earth's history. There have been extinction level events so catastrophic
that it destroyed nearly 80% (or more) known life on the planet at the time. While I have no doubt that humanity is ushering in a new era of
extinction level events - I can't really see it being as devastating as what the Earth has already undergone. Indeed, extinction level events seem to
occur in fairly regular cycles on this Earth. I could speculate that such events happen on other planets which harbor life as well. To what regularity
or severity, I don't know. If life can bounce back and create us, I see no reason why it would could not be so on other planets.
Although I have no definitive proof, I do find the idea of Earth being the only spark of life in the universe preposterous. I find the idea of humans
being the only intelligent life in the universe highly unlikely. I find the idea of aliens visiting Earth to be somewhat plausible - albeit I don't
necessarily think that they are, or that they are behind the UFO phenomena. To accept the stories and conspiracy theories surrounding aliens found on
this site seems to me to be too far of a stretch of logic based on far far too scant few amounts of reliable evidence.
I will say this however - that I believe our first definitive contact with alien life will happen within this century, and I believe that our first
contact will alien life will be in the form of discovering microscopic organisms within our solar system. It will not be intelligent life. There's
enough evidence for the diversity of life in hostile environments on Earth to support the supposition that life may have adapted to thrive in the
upper atmosphere and even space. There's plenty of tests which show that certain bacteria, yeast, molds, etc, can at least survive conditions in
space. Some have even demonstrated their survivability of reentry.