Fermi’s paradox

A)    This is an introduction to Fermi’s paradox:

1. Fermi’s paradox is the apparent contradiction between the lack of evidence and high probability estimates for the existence of extraterrestrial civilizations. The basic points of the argument, made by physicists Enrico Fermi and Michael H. Hart, are:

- There are billions of stars in the galaxy that are similar to the Sun, and many of these stars are billions of years older than the Solar system.

- With high probability, some of these stars have Earth-like planets, and if the Earth is typical, some may have developed intelligent life.

- Some of these civilizations may have developed interstellar travel, a step the Earth is investigating now.

- Even at the slow pace of currently envisioned interstellar travel, the Milky Way galaxy could be completely traversed in a few million years.

- According to this line of reasoning, the Earth should have already been visited by extraterrestrial aliens.

In an informal conversation, Fermi noted no convincing evidence of this, leading him to ask, “Where is everybody?”

2. There have been many attempts to explain the Fermi paradox, such as:

- Extraterrestrial life is rare or non-existent.

- No other intelligent species have arisen.

- It is the nature of intelligent life to destroy itself or to destroy others.

- There is periodic extinction of civilizations by natural events.

- Intelligent civilizations are too far apart in space or time.

- In a multiverse, young universes exceedingly outnumber older ones. Averaged over all universes, universes with civilizations will almost always have just one. [1]

B)    This is a discussion concerning the paradox:

3. Besides the extraterrestrial aliens, there are many illegal aliens. They live among us but we do not pay attention. We don’t care if they live or die. We are so busy getting on with our own problems. Nobody really cares about our own aliens. So why care about other aliens?

4. We keep on destroying everyday our home planet. It is estimated that 40% of all species are already lost. If only half of the species have been known then the number of extinct species may well rise up to 80%. This is called the Anthropocene Extinction. So why should we care about extraterrestrial species when we don’t even care about the species on our home planet? Is it just because we find this way an alibi? Is it because there are some idiots searching for aliens with telescopes, ignoring the earthly species or their own kind?

5. It is true that our technology is relatively primitive. Our radio signals can hardly reach Alpha Centauri, the closest solar system. Even if a civilization like our own existed there, we wouldn’t know anything about their existence. (This aspect is reciprocal.)

6. But let’s suppose that an advanced civilization on some exoplanet in the Milky Way has already visited the Earth. How would we know about them if they are stealthy? How would we know about their existence if they leave no trace? What could we make out of them if they are so advanced that they appear to us in ways we cannot explain or perceive?

7. Let’s even assume that they make their appearance in such a way that they are visible to us. Would our governments let us know about their existence? How could we distinguish between genuine and fake photos of their spaceships? Would we believe someone telling us that he saw them just because he said so? Would we believe in our own eyes if we saw a flying saucer in the sky, or would we just blame our imagination and ignore the whole incident? Would we dare speak about the incident to somebody who would think we are crazy?

8. Perhaps our belief in aliens is nothing more than an extension of our belief in God. But such a belief is very vague and it is largely based on ignorance. Usually we are afraid of what we don’t know. So what if we had a close encounter of the third kind? What if some aliens came and abducted us onto their spaceship to do some tests on us? Would any true experience be retained in our memory? Or would we just repress the whole incident and dispose of it as a bad dream?

9. What can we really make out of something about which we don’t know anything? Physically we will dress it up with our own perception and experience, and we will interpret it according to our own knowledge and expectations.

10. But if the true aliens ever came, such an event would cause a culture shock. Panic and fear would prevail, governments would fall, members of religious groups would commit mass suicide, and the whole society would collapse. Finally we would wish that they had never come.

11. And such reaction would be the result in the case they were friendly. What if they were hostile? What if they needed a new planet to settle because their home planet could not support them any longer? What if, no matter how peaceful they might be, they needed to colonize our planet for reasons of mere survival?

12. It is true that we don’t know much about the universe. We know much less about the nature of spacetime. What is the average density of extra-terrestrial civilizations in the universe or in the Milky Way? What if the universe is truly immense, practically infinite, while what we call the observable universe is just a tiny part of an immensely larger distribution of universes like our own?

13. If this is true then we could be the only civilization in what we call the universe. But if there are ways to travel in spacetime yet unknown, ways to travel from place to place infinitely faster than the speed of light then there could be an infinite number of alien civilizations in an infinitely large number of universes, in a never ending distribution of spacetime.

14. In order to realize this problem of scale, let’s take the following example. Let’s suppose that we are a colony of ants. Then what we would call our universe would be the space of a backyard. The surface of the Earth is about 500 billion square meters.  If the space of our territory were 100 square meters, there could be another 5 billion ant colonies out there. If the space of the backyard ant colony is compared to the size of the observable universe which we are aware of, there could be another 5 billion civilizations in other regions of spacetime, in other universes which we cannot observe.

15.But beyond the problem of the size and nature of spacetime there is an even deeper problem. Even if there is another civilization relatively close to us- assuming interstellar space as we know it- would they be recognizable to us? Would they be bipedal, with eyes, ears and a head? Would they use some form of language to communicate? Would they have some form of arithmetic, and a way of thought based on logic? Would they have any material form at all? Could they be invisible like spirits, moving along space in ways imperceivable, appearing to us as lights in the sky, or as ghosts in the dark?

16. Therefore an ‘Unidentified Flying Object’ (a UFO) could be anything which we don’t know about, from a new experimental aircraft of some government, or an unknown physical phenomenon, to an incomprehensible alien lifeform, which needs not be either ‘living’ or having a ‘form’ as we know it.

C)    So what is the ultimate answer to Fermi’s paradox?

17. In order to answer the question “Where are they?” we may have first to answer the questions “Where is ‘where?’” “What is space and time?” “What is an ‘alien lifeform?’” Have we wrongly been searching for something that looks like us (using radio signals for example?) Even if there is something out there which looks like us, do we really want to communicate?

18. Would the purpose of communication be something more than the satisfaction of our or their curiosity, a primordial greed or naive wish to explore and know everything about the universe? Is this enough at a time when our own greed and irresponsibility has turned our home planet into a junkyard? Do we really deserve a place among the advanced civilizations which might exist in the universe, or should destructive, immoral and incorrigible species like our own disappear as soon as possible, like an over-crowded ant colony after a heavy rainfall?

D)    Thus the Fermi paradox:

19. It is certain that life exists in the universe. Take us for example. But “Where is everybody?” “Is there anybody here?” “Who really cares?”                       

[1]: [https://en.wikipedia.org/wiki/Fermi_paradox]

9/3/2018

Image: The Arecibo message is a 1974 interstellar radio message carrying basic information about humanity and Earth sent to globular star cluster M13 (some 25,000 light years away) in the hope that extraterrestrial intelligence might receive and decipher it.

[https://en.wikipedia.org/wiki/Arecibo_message]