The universe is about 14 billion years old, atleast the start of this universe. Maybe there were an infinite amount of big bangs before ours? The cycle could go: big bang --> universe expands until it can't expand anymore --> universe collapses into extremely dense ball --> big bang. Anyway, that's not really what I wanted to talk about, we'll leave that topic for another day. What came into my mind was something that I'm sure everyone has thought about before and probably argued about. Is there intelligent life somewhere out there in the universe?
Odds seem to be undeniably in favor of...yes. In our galaxy there are estimated to be upwards of 250 billion stars. Some scientists say there are more than 100 billion galaxies. So, lets say there are about 2.5 sextillion (2.5 x 10^21 ) stars in the universe. Then let us assume that the earth is not some kind of anomaly and therefore is somewhat typical, atleast when referring to astronomical odds. With this assumption, we see that there should be billions of habitable planets in the universe. Given that the universe spans 14 billion years, it then should not be unthinkable that life has evolved on these planets, from mere 1 celled prokaryotes to species as smart as humans and some most definitely smarter. Unless you're some kind of god freak that believes we were created as the only intelligent species, reason leads us to believe that there are aliens somewhere, probably in our own galaxy.
Okay, so we've come to the conclusion that life outside of our planet must exist. It has to right? The odds against it are infinitely, impossibly low. Why then is there no evidence? No proof of alien communications? Well maybe there is, maybe the government just hides it (area 51 for example). I don't know what I think about that subject, maybe aliens really did crash on our planet, but we don't know for sure, so we have to assume that they haven't. So back to the question, if there is intelligent life somewhere in the universe then why haven't we found them. I'll mention a couple possibilities.
First, the universe is just too big. The odds of a chance encounter are incredibly slim. The sun alone is 93 million miles from earth. The next closest star is 4.3 light years away, or about 25 million million miles. Travelling as fast as our current technology allows, it would take about 100,000 years to get to Proxima Centauri. And that's when we know where we're going. Even if they could travel close to the speed of light, aliens finding earth would be like finding a needle in a stack of needles.
Next is an idea that ignited the fire for writing this post. What if the amount of technology needed for interstellar travel is beyond the point of survival? Take the LHC for example, this obviously didn't cause the end of the world, but maybe something like it could. What if civilizations just destroy themselves with their technology before they have the chance to leave their planets? I recently read an article about advances in nanotechnology, stating that we are getting closer to producing self replicating nanobots. Some of you have probably heard about this idea before, which some fear might lead to "grey goo," an end of the world scenario. Basically, these nanobots consume materials to replicate themselves, eventually consuming all of the matter on earth.
There's more I'd like to talk about, but I have some studying to do. Feel free to share your own ideas, because I'm sure a lot more could be said about the topic that I didn't touch on.