Theories, Speculation, and Discovery
June 7, 2024
In 1950, Enrico Fermi asked his colleagues why no intelligent alien species had ever been observed or detected, given the age of the universe. And given the size, he wondered why no life form had conquered the universe in the past. His giant string of questions related to the presence of alien life in the Universe is known as the Fermi Paradox.
Numerous theories and speculations have been made attempting to both explain Fermi’s paradox or provide evidence to which alien life is still a very real possibility. “An Explanation for the Absence of Extraterrestrials on Earth” by Michael H. Hart dives into many theories that all strive to explain the vacantness of aliens. Hart proposes physical explanations in which extraterrestrial creatures could never reach our Solar System due to some physical barrier preventing space travel between galaxies, such as life span or equipment endurance. However, he also points out that aliens might have completely unique life spans and different biological systems that humans cannot comprehend, allowing them to maneuver through barriers that would prevent human space travel. Hart additionally expands on this by mentioning how extraterrestrials might possess greater technologies, such as powerful and efficient engines, or a ship meant for such a journey to overcome technological hurdles preventing humans from distant exploration. Hart also highlights sociological explanations, articulating the idea that aliens might not be interested in space exploration or have different priorities stemming from their psychological beliefs. For instance, an alien race might not be interested in space travel or exploration but rather engrossed in traditions or activities that originate from their own culture. However, Hart explains that it is wrong to assume that this hypothesis will apply to every alien race that has ever existed, and their entire history as well. Maybe aliens do have intentions to explore space and even conquer it…but then why haven’t humans detected any signs of this occurring?
A good answer to this is the Dark Forest theory, where people are dropped all throughout a dark forest and are told to survive as long as possible, similar to the Hunger Games. An encounter with another contestant in the game would likely result in death or mass outbreak, as neither person would know the other person’s intentions (neither side knows if the other is coming in peace, and the safest course of action is to kill/destroy the threat). This hypothesis can explain how many alien civilizations will fear space exploration, as coming across a different species might be dangerous. It can also illustrate how those who do explore and come across each other might end in the demise of both civilizations, as further explained in the Self-Destruction Hypothesis.
While theories surrounding the Fermi Paradox are always exciting to think about–additionally complicating the topic of alien existence–mysterious signals and potential signs of life in the universe excite astronomers and scientists who hope that aliens do exist. While no concrete evidence has been passed that neither proves aliens a reality nor disproves their presence, speculations and new discoveries continue to be captivating.
A strange phenomena known as a Fast Radio Burst (FRB) is the basis for some speculations surrounding extraterrestrial life and was first discovered in 2007 when a radio telescope picked up unusual detections of radio waves, lasting less than a millisecond long. Originally thought to be a communications systems issue with the radio technology on Earth, to glitches in the detectings of these radio waves, scientists eventually learned these occurrences were real, and coming from billions of light years away. FRBs 121102 and 190520 are both radio bursts that have emitted repeating bursts unlike the abundance of FRBs picked up by Earth—exciting those who believe that this strange behavior could indicate intelligent life rather than astronomical phenomena and there are arguments on both sides debating this. Manasvi Lingam and Abraham Loeb proposed that FRBs could be connected to alien life in 2017 by speculating extraterrestrials' usage of artificial beams to power light sails in distant galaxies. However, FRBs can also be generated from “starquakes” of magnetars (formed from the collapse of a supernova into some neutron stars with exceptionally strong magnetic fields) due to stress or reconfigurations from such fields, which is often used accompanied alongside other evidence to rebuttal claims made that FRBs stem from aliens. Stated on phys.org by SETI scientist Dr. Sofia Sheikh, “We're narrowing down the source of FRBs, for example, to extreme objects such as magnetars, but no existing model can explain all of the properties that have been observed so far”
While work is constantly being done to uncover the true source of FRBs and settle the speculations over the correlation with these radio bursts and extraterrestrials, new discoveries on exoplanets—having life-supporting properties—have led to stronger hypothesizing surrounding the potential existence of aliens. For instance, the exoplanet K2-18b, originally found by Hubble in a habitable zone of a star system 120 light years from our solar system, was found to have methane, CO2 and water in its atmosphere by the JWST’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) and Near Infrared Spectrograph (NIRSpec). Furthermore, the absence of ammonia detected has led NASA to believe that this exoplanet could potentially be hydrogen-rich with the presence of an ocean as well.
But even this evidence is weak. As Hart highlights that aliens might have completely different life spans or methods to overcome space travel difficulties faced by humans, he emphasizes the lack of comprehension we have on aliens. Aliens might live in atmospheres that would be fatal-causing for humans, or might not even need an atmosphere to live. Or as Hart states, aliens might not be warm-blooded like we are. Until more findings are made, however, we can only speculate.