The Zoo Hypothesis: The Creepy Solution to the Fermi Paradox (Video - 19mn)

  I am a believer in the Zoo hypothesis, but not only that. It all starts with the Rare Earth hypothesis. Living planets are rare and far away from each others. Most galaxies are unsuitable for life with too few elements for complex life to appear. Likewise, a large part of every galaxy is truly dangerous with too much radiations at the center and too little activity on the periphery. Reason why we are ideally located on the rim of a large, well evolved galaxy. 

 Then the Earth is the next hint. Close but not too close to a stable, long lasting star which doesn't flare or pulse or anything really. These are a minority compared to the huge numbers of dwarf, red stars which are also more variable. Medium size planet stabilized by a giant (relatively speaking) moon, not too much water, you end up with an ocean world like Europa, the moon of Jupiter, or not too little. Smaller planets will mostly have no atmosphere at all, Mars atmosphere is only 1% of the density of ours, or too much like the gas giants of our solar system. Likewise larger rocky planets will have a crushing gravity which guaranty that whatever may crawl there will not grow very big. 

 And then you need time for evolution to work its magic. Billions of years according to the only example of life we know. Surprisingly, life seems to occur early so although we do not yet understand the exact mechanism, it cannot be extraordinarily complex, but then it takes forever to create the nucleus and later multicellular organisms. Mitochondria, chloroplast and other miracles of evolution certainly take time and serendipity. A billion years can pass with nothing much happening as was the case on Earth. Why not 5 or 10? 

 By then a Cambrian type explosion happens which must be the next stage on every living planet. Everything gets fasten from then on. But evolution can stop due to major cataclysms. The Permian extinction for example wiped 90% of all species 252 million years ago. It could be 99% or even 100%!    

 We then get to intelligent beings. One thing we can be certain of: Life will necessarily create intelligence. We have intelligence in mammals of course but also in birds, parrots for example, and invertebrates such as octopus. Different paths, same results. Intelligence is guaranteed. 

 The rest is better documented since we know how intelligence created civilization. But there our experience stops. What happens later? We don't even have a clue.

 Or rather we do! As we observe the cosmos, the one thing we do not see are Star Trek or Star Wars spaceships darting across space. But could we actually see them if they existed? Or are these more likely the product of our imagination in the last century. A little more advanced than Jules Verne cannonball to go to the Moon but barely?  

 But then of course, on the other side, is the incredibly diverse zoo of UFO ostensibly visiting our planet with literally millions of accounts of pilots and other professionals of objects which are clearly not natural and often unbelievably strange. "A metallic sphere in a transparent cube" or "two giant linked green donuts" certainly qualify as rather unnatural and odd objects especially if they also happen to fly!       

 So, what to make of all this? 

 We cannot even predict where exactly AI will be or do in 10 years so needless to say that we have no clue what anything more advanced than us would look like. 

 This is why I personally believe in the zoo hypothesis. Nobody will contact us, ever. Such contacts probably make no sense. We will likewise never "find" advanced civilization according to the principle that "Wi-Fi" is invisible to stone age people. Conversely, soon enough, if we manage to not blow up everything, a big if, we will relatively quickly get hints that other living planets do exist. This should happen in the next 10 to 20 years. At some stage we'll get some "readings" from the composition of the atmosphere of alien planets which will show some mysterious unexplainable imbalance such as the presence of free oxygen. Then, we'll know we're not alone. Out of reach certainly, probably 20 to 30 light years away but not out of sight. Another 10 years and we will quickly be able to "see" such alien world.

 So, eventually, we'll get the answer to that question too, but the hard way. No spaceship on the lawn of the White House. No invasion. No nothing. Extra-terrestrial life will morph very slowly from Science Fiction to science over the years.