Humans are becoming cognizant of two daunting possibilities: they either are or are not alone in the universe. Some assert that the former is more terrifying, while others contend that the latter is. Regardless of which is true, extraterrestrial life has still yet to reach out to humans. The ultimate conundrum, like Enrico Fermi famously asked, is “where is everybody?”
Scientists have explained this lack of communication by proposing the existence of the “Great Filter,” a theoretical wall that barricades some stage in a timeline, beginning with life occurring due to the right conditions and ending with the colonization of the galaxy by an intelligent species. Since it is unknown at which point the filter occurs, it may either exist either before or after current human existence. An existence before implies that only a select few civilizations were able to surpass the filter and remain, humankind included. Should the wall be after the existence of humans, civilizations before must have already hit the wall and stopped existing, and humans are doomed to face the same fate. As a result of the “Great Filter”, other lifeforms are unable to exist, are too limited, or will stop existing soon.
Astrobiologists are united in their theory that there must exist a plethora of planets within the infinite universe that holds the necessities to sustain life — necessities that would eventually lead to the formation of intelligent life and allow it to embark on a journey similar to Earth’s. However, there is no concrete evidence to validate this conclusion. This theory is known as the Fermi Paradox, named after the famous scientist Enrico Fermi. Theoretically, the conditions for life to thrive beyond Earth are undeniable, yet not a single extraterrestrial being has reached out.
There are three possible explanations for this paradox, each with its own uncertainties: aliens do exist, aliens have yet to contact humans, and aliens do not exist. Starting with the first, some researchers theorize that aliens have already been to Earth and left evidence that has yet to be discovered. However, there is still a lack of concrete evidence to suggest that anyone besides humans has ever set foot on Earth. Another theory is that humans descended from aliens. If this was the case, though, there should be some proof of the original alien species, which there is not. The last theory is that humans are trapped on Earth in a zoo-like simulation, isolated from the rest of the universe and monitored by aliens.
A speculation within the category that aliens have not yet facilitated communication is that messages have not reached Earth yet due to the time it could take to travel through space. However, the universe began billions of years ago, so it is unlikely that a message would require longer than this to reach humans. Additionally, alien intelligence may surpass those of humans and be trying to communicate through methods unfamiliar to those on Earth or have no desire to communicate. The limitation of these theories is that there are an infinite number of galaxies, so there should be at least one civilization that understands the communication methods that humans utilize, match human intelligence, or be curious about human existence.
“Astrobiologists are united in their theory that there must exist a plethora of planets within the infinite universe that holds the necessities to sustain life — necessities that would eventually lead to the formation of intelligent life and allow it to embark on a journey similar to Earth’s.”
“Humans are becoming cognizant of two daunting possibilities: that either they are or are not alone in the universe.”
Theories that fall under the third category, that aliens merely do not exist, bring to light the facts that habitable zones are extremely rare; the habitat to nurture life has to contain water and be the optimal distance from a star, and the galaxy’s harsh conditions limit life. As plausible as these theories may sound, they too are improbable; although humans could be the first and only lifeforms in the universe, the conditions that led to their life are neither specific nor special to just Earth. The sun around which humans revolve is an average star, the same as the billions of others that formed and also allowed life to be possibly eons before.
Every explanation has limitations, and humans may have to come to terms with the fact that they may never know why extraterrestrial life refuses to communicate. Perhaps, for the sake of human sanity, the question of whether we are truly alone in the universe or not should be left unanswered.
Image courtesy of Pixabay
