Where is everybody?
technology and an intelligence like ours. Whilst there is evidence that alien chemistry, if not culture, is likely similar to life on Earth (for example, carbon is the most diverse element, able to form more molecules than every other element combined, 6 meaning aliens will likely also be carbon-based), there is nothing that necessitates aliens having to look, think or communicate anything like us. The anthropomorphism in all of us could very well be nothing more than wishful thinking; alien life could be so alien that it is absolutely impossible to converse. Even if aliens weren’t so different to us, t he biggest barrier to two-way communication could simply be technology. Consider this: homo sapiens emerged in Africa about 200,000 years ago, yet it was only about 100 years ago that we discovered radio waves and began to send detectable signals into space. If any alien lifeform had attempted to send us a radio signal any time in our existence before this discovery, even though we would have considered ourselves an advanced, intelligent, civilized species, we would have been completely ignorant of it. Now consider what will become of our technology in the next few millennia. Anyone who has seen Back to the Future will know that predicting the future is an incredibly difficult challenge, yet do you really imagine that we will still be using the exact same method of communication as we do now? It might be that we are currently occupying the tiniest slice of our existence where we can send and receive radio waves, and thus only other species who occupy this exact same window will be able to communicate with us. Any species even slightly more or less advanced will be deaf to us, and we deaf to them. Thus, there may be aliens out there, but we are simply looking for them at the wrong time. In fact, time might just be the biggest factor in our fruitless search for extra-terrestrial life. The simple truth of the matter is that at most we’ve been sending out radio waves for a century or so, and because of the finite speed of light, this means that our radio-bubble (the distance into space that our radio waves have penetrated) has a diameter of only 200 light-years, making up just 0.2% the length of the Milky Way galaxy! 7 Perhaps there are alien species, but they are simply too far away to have heard us yet. This could explain why we haven’t heard from younger civili z ations like our own, but still doesn’t explain why we haven’t heard from older species which should presumably have been broadcasting signals for millennia. In conclusion, the lack of observation of any extra-terrestrial life is both perplexing and worrying. Either there are no intelligent aliens, implying that humanity and Earth is exceptionally lucky, unique, or heading towards almost certain doom; or there are aliens, but they are unable or unwilling to communicate with us. Personally, I find it unlikely that there are large, highly advanced civilizations spanning the galaxy unbeknownst to us, as such a civilization ought to be emitting all sorts of signals (even unintentional ones) into space that we should be able to pick up. Even if their technology has advanced beyond the use of radio waves, evidence of their civilization, such as Dyson spheres (massive structures that surround stars and harvest their energy) should be visible. That raises the question of why there are no advanced civilizations, despite there being a little less than 13.8 billion years for them to arise (humanity arose on a planet just 4.5 billion years old, for context). This makes me believe that the Great Filter theory is to blame here, and intriguingly, we may be able to narrow down where those filters are as we search for life in our solar system; if we find that life has developed to a certain stage
6 Information today . (11/04/18) ‘Neil deGrasse Tyson - Mind-Blowing Facts About The Universe - Top Speech’. 7 Lakdawalla 2012 .
233
Made with FlippingBook - Online catalogs