The Fermi Paradox and its Great Filter

One well consumed topic in the debating world is extra-terrestrial life.

The possibility of these foreign beings’ existence fills us with an overwhelming number of questions and invades our heart with a warm though often scary astonishment.

   In my experience, most people with whom I have had the opportunity to exchange were most definitely certain that these beings do not only accommodate Sci.Fi scriptwriter but truly exist and that their future delightful discovery awaits us all.

This is all very exciting, but let’s have a look at it in an objective, scientific way.

It is true that in the observable Universe, there are approximately 100 billion galaxies, each of them with at least as many stars and even more planets... But it would not be very effective to take into consideration anything other than our local group, since with the expansion of the Universe, it would be impossible to reach any further ! Therefore, to be able to have an interaction with a space being, we must concentrate on our home galaxy, the grandiose Milky Way. 

The Milky Way presents over 10,000 stars for every grain of sand on Earth . It is estimated that about a fifth of these stars have an Earth-sized planet located in the Goldilocks-zone: the area around a star where the temperature is just right for liquid water (and therefore a possibility for life) to form on this planet.

If only 0.1%  of these planets developed life, there would still be over a million populated planets in our local group.

    Moreover, the earliest known life form on Earth, time wise, only stands for 27% of the Milky way's existence and we, as humans, only for 0.0019%.

This adds multiple billions of changes for life to develop on other planets in the past.

    

   After emerging into a civilization, life has every reason to transform into a bigger one. These reasons can be 

- economical, in our scale : as with the exploitation of America,

- for survival, as Stephen Hawking wants us to leave Earth since it is going to die soon,

- to avoid tensions, for example when Abraham asked Lot to separate, to not have any quarreling, etc.

The Kardashev scale explains that we would start with a type 1 civilization, which can use all the energy on its planet, then a type 2 which can do the same with its sun (Dyson sphere), type 3, with all its local group, etc.

(Earth is currently at 0.73).

But where is all this life? Shouldn't space be filled with advanced technological spaceships? 

This is what is known as the Fermi Paradox.

Enrico Fermi was an Italian physicist from the first half of the 20th century and creator of the first nuclear reactor.

 He found sense in his paradox by wondering if there was a limit to technology (including that it would not be possible to become a type 2 or 3 civilization) or by adding some kind of a great filter.

If there really is a technological limit, it would be the end of our Paradox, meaning that we will never find life and will just have to live alone. But scientists are perplexed by the idea.

Another option, the great filter is one or several monstrous events which make it impossible (or extremely hard) for life to pass to the next level of civilization ( type) destroying everything in the process.

One can therefore assume two different options:

- In the first case, this filter may be behind us, making us special and maybe the first civilization or even form of life. This barrier could have consisted of a great number of factors needing to create life or the rarity of our planet.

- Or more likely, in the second case, this great filter is in front of us and it is only an amount of time before it destroys us... It could consist of an inevitable disease, artificial intelligence, nuclear war, our own bad maintenance of Earth or even the first type 3 civilization which annihilates life when it is developed enough to avoid competition (Hawking and others have warned us about messages in space, which could attract an ancient Godlike civilization).

Odds seem to lean towards the second possibility since scientifically the barriers that Humans have passed don't seem too complex.

After what has been said, as Nick Bostrom explains well, the worst possible information that could be presented on the news is the discovery of Aliens. Indeed, finding other beings (the more complex, the worse) would remove the possibility of the filter being behind us, of us being unique and therefore that the barrier is in front of us !

In conclusion, I hope that the next time you have the breathtaking opportunity to look up to the stars, you won't be so excited by the idea of finding extraterrestrial life. And if you are a conspiracy believer and that you think the government hides Aliens in Area 51, I'm afraid that we are all already doomed !

On a more serious note, we, as human, are great thinkers, creators but we are not perfect. We should take more time to think about consequences before actions since we only, or at least so far, have one Earth and can easily destroy it and ourselves in the process.

For the moment, we can only assume that we are the only living creatures of this beautiful architecture of the cosmos which is our home. This thought leaves us with the unique and spectacular gift of being its feeling and thinking, to be a part of its grandiose beauty, to be its mind and soul.

James