Hello and welcome back on Curiosity.gr. In today’s article I want to talk about the Fermi Paradox.
There are innumerable galaxies in the universe, which each contain endless stars and planets. Only our galaxy, the Milky Way, is a hundred thousand light years wide and consists of up to three hundred billion stars, twenty billion of them are similar to our sun. Scientists estimate that four billion of these sun-like stars have at least one larger planet in the habitable zone, the area in a star system where the perfect conditions for life exist (it is neither too warm nor too cold).
The universe is 13.8 billion years old, so extraterrestrial life would have had enough time to develop. Due to the age of the Milky Way and the numerous habitable planets in our galaxy, life outside of Earth should actually be very common and we should have noticed extraterrestrial life long ago or at least should have found evidence of its existence. The fact that we have not yet found any reference to any extraterrestrial civilizations therefore appears contradictory and is called the “Fermi Paradox” after the physicist Enrico Fermi. Fermi discovered this contradiction in 1950 and asked himself the famous sentence: “Where is everyone?”.
There are numerous explanations and solutions for the paradox, none of which can be confirmed or refuted. I would like to explain a few of these approaches in this article:
The fact that we have not yet been able to discover any alien life forms could, for example, be due to the fact that the distances between different planets in the universe are so huge that communication between intelligent living beings is made almost impossible because nothing can move faster than light. This is made clear by the following: We have been sending radio waves into space for about 100 years. So extraterrestrial life could only perceive us in this relatively small radius of 100 light years around the earth. If this was the case and they contacted us back, an answer would take another 100 years.
Another solution to the paradox is that our way of communicating is not understood by aliens, or that they ignore us. Conversely, it is possible that they have already contacted us but we do not have the necessary technology to receive their message. Or we are actually all alone in the universe.
The rare earth hypothesis goes against the general assumption that the origin of life like ours on earth is common. In addition to the condition that a planet must be in the habitable zone, other conditions may have to apply so that earth-like life can arise.
If there really are no interstellar active, intelligent species, there could be various reasons. Three of them that are considered to be particularly likely are the so-called large filters.
A filter represents a hurdle in the development of a species into an interplanetary civilization, which is so enormously difficult to overcome that only a tiny fraction succeeds, the rest dies out.
The first of these filters is the forming of life itself. There has to be a planet that is in the habitable zone who has an atmosphere and ideally a magnetic field and is in the right place in the Milky Way so that it is not constantly hit by asteroids, for example. The right molecules and the right conditions must exist on this planet for life to arise and develop.
The second filter is the development of intelligent life. That we humans have such a large brain, for example, which enables us to understand and solve complex, logical problems and to develop technologies, cannot be taken for granted. A large brain is not particularly beneficial to the species in the early stages of evolution because it consumes a lot of energy without being particularly helpful. Therefore, intelligent species may be extremely unlikely to even emerge.
The British physicist Stephen Hawking, on the other hand thought, that the emergence of intelligent life outside the earth is not very uncommon. According to him, we have not yet discovered any extraterrestrial life because there is a third filter Mankind has not yet overcome. Hawking says that it may be in the nature of a technical civilization to self-destruct. Nuclear war, climate change or overpopulation – intelligent life becomes unstable at a certain point and consequently self-extinguishes.
These were the most likely reasons why we have not yet been able to discover any alien life forms. Let’s hope Stephen Hawking was wrong!
Sources:
https://en.wikipedia.org/wiki/Fermi_paradox,
https://waitbutwhy.com/2014/05/fermi- paradox.html,
https://www.seti.org/seti-institute/project/fermi-paradox,
https://www.bbvaopenmind.com/en/science/physics/five-solutions-to-the-fermi-paradox/
Written by: Simon