What is the Fermi paradox? It is the fact that if life in the universe is so common, we should have found signs of it.
Enrico Fermi was an Italian physicist. He received a Nobel Prize for physics in 1938 and he was involved with the Manhattan Project in the Second World War. He died in 1954 from cancer, probably caused by working so close to the nuclear pile during the Manhattan Project. This paradox is named after him, although it seems that it was just a lunch time conversation that Fermi participated in and the name Fermi’s Paradox wasn’t used until 1984. Fermi was talking to Emil Konopinski, Edward Teller, and Herbert York and Fermi asked them “Where is everybody?”
The Fermi Paradox first looks at the probability of there being intelligent life on other planets. There is no way of knowing that and any answer can only be an educated guess. The Drake Equation is an attempt at making a formula to do just such a thing. First, we have to assume that we are not special. If life, and intelligent life, is just a series of chemical chances and the process of evolution if given enough time, then there is no reason not to think that there would be intelligent life on other planets. Let’s look at that first.
We can’t know what life needs to start. All that we can know is what life needs to start here on Earth. So, if we take that as a guide, we need a sun that is the right temperature, we need there to be planets orbiting it, we need a planet that is in the Goldilocks zone (not too close to the sun to be hot and not too far away to be cold), we need a stable environment and enough time for evolution to do its work. So, there are approximately 100 billion stars in the Milky Way Galaxy. There are approximately 2 trillion galaxies in the universe, which gives roughly 200 sextillion stars. That’s 200,000,000,000,000,000,000,000. Let’s roughly guess that the % of those stars that are the right size are 0.1%. That is 20,000,000,000,000,000,000 stars. Let’s say 0.1% have planets. That’s 2,000,000,000,000,000 planets. Let’s say 0.1% have a planet in the Goldilocks zone. That’s 200,000,000,000 planets. Let’s say life starts on 0.1% of those. That’s 20,000,000 planets with life. Let’s say 0.1% of those survive long enough for intelligent life to evolve. That’s 20,000 worlds with intelligent life. Now, that 0.1% is just random, but the point behind the Fermi Paradox is if there is so much likelihood of other intelligent life, why haven’t we found any trace of it. There are many possible answers to this paradox. Here are 8 of them.
1. There isn’t any other life out there. We are unique and we are alone. This seems very unlikely. If intelligent life was able to evolve here, there is no logical reason why it couldn’t evolve elsewhere.
2. The distances are just too great for any two intelligent civilizations to meet. This is a very likely reason. If another intelligent species evolves in the Milky Way Galaxy, it could be up to 100,000 light years away from us. If it evolved in another galaxy, it is even further. If travel at the speed of light becomes possible, that is still 100,000 years or more. If that species set off now and reached Earth in 100,000 years, will humans still be here? Even our radio and TV signals, which are travelling at light speed, are very unlikely to ever reach any other star.
3. The times don’t match. We evolved intelligence about 2 million years ago. That is 0.04% of the age of Earth. It is 0.014% of the age of the universe. What are the chances that another form of intelligent life evolved at exactly the same time that we did? Pretty small. It is like the opening of Star Wars: “A long time ago in a galaxy far, far away.”
4. Civilizations don’t last long enough to leave their own worlds. Maybe intelligent life is destined to destroy itself and its world before it can send out any signals.
5. Intelligent civilizations don’t want to signal their presence. Maybe, for whatever reason, they want to remain hidden.
6. Intelligent civilizations have signaled their presence, but we don’t understand the signal. Maybe it is something that is beyond our comprehension.
7. There is one super powerful intelligent civilization that is going round destroying every intelligent civilization that makes itself known.
7. Alien civilizations have made contact with us and they are here, amongst us.
There is no way of knowing the answer to any of these questions. However, recently, astronomers have been able to see much farther than before and they have found that exoplanets are far more common than was believed in Fermi’s time. Perhaps, one day, we will have an answer to this question. And this is what I learned today.
Photo by Hristo Fidanov: https://www.pexels.com/photo/milky-way-galaxy-during-nighttime-1252890/
Sources
https://www.livescience.com/fermi-paradox
https://en.wikipedia.org/wiki/Fermi_paradox
https://en.wikipedia.org/wiki/Enrico_Fermi
https://www.seti.org/fermi-paradox-0
https://royalsocietypublishing.org/doi/10.1098/rsif.2022.0029
https://theconversation.com/how-many-stars-are-there-in-space-165370
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