"Where is Everybody?": Possible Solutions to the Fermi Paradox by Aldrin B. Gabuya


In this two-part series by guest writer Aldrin Gabuya, we tackle the Fermi Paradox and a few of the several hypothetical explanations that have been proposed by scientists. 

"Where is everybody?"

This simple question has influenced science for the past 60 years, and changed the way we think about the universe. This is known as the Fermi Paradox, after Enrico Fermi, the Nobel Laureate who was awarded for his contributions to nuclear and particle physics. He uttered this question at a dinner with other physicists as they discussed extraterrestrial life in the 1940's. 

He proposed the following: given that there are numerous galaxies containing billions of stars, in turn possibly housing planets that could harbor life and advanced civilizations, why don't we see any evidence of their existence? This idea drove scientists towards the search for extraterrestrial life and intelligence, and led to the founding of organizations such as the SETI institute. Numerous highly advanced technology has emerged since then to aid with the search. 


In 1959, physicists Giuseppi Cocconi and Philip Morrison made the first attempt to observe alien civilizations using microwave radio as a medium of communication. In 1961, physicist and astronomer Frank Drake created an equation that could be used to calculate the estimated number of advanced civilizations in the Milky Way Galaxy. Frank Drake later continued his quest using radio communication. However, none of the three scientists were fortunate in their search.

Cocconi, Morrison and Drake are considered today as the pioneers of SETI (the search for extraterrestrial intelligence), and as time has passed, other SETI-oriented projects have been established such as Project Ozma, SERENDIP, and the Planetary Society.

But what could explain this paradox? Why don't there seem to be signs of intelligence in our observable universe? Scientists have proposed a number of hypothetical solutions, and we will take a look at some of these ideas one by one. 

1. WE ARE ALONE

Possibly the simplest answer to the question: We don't see alien civilizations precisely because we are the only living civilizations existing currently in the universe. Life is so rare, that it is only harbored on Earth. This is also known as the Rare Earth hypothesis. The Great Filter is a related hypothesis which suggests that there are barriers that need to be overcome by civilizations before they can achieve the ability to travel in space. If not overcome, these civilizations could self-destruct.

2. THERE ARE ALIEN CIVILIZATIONS, BUT THERE IS NO COLONIZATION OR COMMUNICATION 

This idea has three categories: 

A. Technological Difficulties 

Though it continues to evolve, our current technology lacks the capacity for interstellar travel, preventing us from searching the distant reaches of space. There is no doubt that we can do this in the future, but it would be a very difficult task. It could also be the case that other civilizations are sending signals to communicate with us, but we do not hear or listen to them. 

Perhaps, their signals do not align with our main means of communication: the electromagnetic spectrum. Taking into consideration the vastness of the universe, it might take much time for the signals to reach us, or the signals could be too weak for our equipment to detect. In other words, our technology at the moment is still too primitive for this task.

We could also be lacking the technology to gather the energy needed for interstellar travel. As a Type 0 civilization, we only use all of the resources of our home planet for producing energy. Because of many reasons, we can't use all of it to accomplish the challenge of space travel. In contrast with other types of civilizations, a Type 2 civilization could acquire all energy from their home star by building a Dyson sphere, a large, thin-walled sphere of numerous solar arrays engulfing the distance between the planet and their parent star. They could also use numerous smaller spheres called Dyson bubbles, which are scattered in space around the parent star. 


According to Freeman Dyson, the theoretical physicist who postulated the concept in the 1960's, as these spheres absorb all the energy from the parent star, they would then emit infrared radiation outward from the surface. This can be perceived by our infrared detectors.

B. Sociological Considerations

What does society think about the search for extraterrestrial life? Some believe, out of practicality, that these projects are unnecessary. Instead of using money, time and effort for SETI, we must use them instead to resolve global concerns such as climate change, war, and poverty. Others find the Rare Earth hypothesis to be emotionally consoling, content with the idea of us as being special, with a universe perfectly designed for us.

We should also consider that interstellar travel takes a very long time, with distances covering millions or billions of light-years. Our means of travel (rocketry and spacecraft) lack the ability to travel in hyper velocities, so it is understandable that civilizations (including alien ones) could not maintain their interest towards this matter.

In addition, people could also fear the possibility of alien abductions and invasions, a possible reason why some are reluctant to explore the universe. 

C. Self-Destruction

This idea states that civilizations cease to exist before they can attain interstellar travel. In physics, we know that for matter to travel at hyper velocities, it would need an enormous amount of energy. One good source for this would be nuclear energy. But if mishandled, executing this could have huge risks, such as explosions due to the release of concentrated amounts of energy.

If we use other energy sources such as fossil fuels, solar energy, or hydroelectricity, it could lead to a scarcity of these resources for other means, as well as consequences to the environment. This scenario could have happened to other civilizations, which is why we lack traces of them. 


In the second part of this series, we look at three more hypotheses regarding the Fermi Paradox. Have questions for our scientists? Leave a comment below. 

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