A recent study potentially casts doubts on the likelihood of humanity discovering technologically advanced extraterrestrial civilizations.
The research, co-authored by eminent astronomer Dr. David Kipping and astrophysicist Dr. Geraint Lewis, argues that the odds of uncovering an advanced alien race are remarkably low due to a narrow detection window determined by the unknown rates at which these civilizations emerge and vanish.
Dr. Kipping and Dr. Lewis make their case for a lonely cosmos in a new paper published in preprint on arXiv.
“In ecological systems, be it a garden or a galaxy, populations evolve from some initial value (say zero) up to a steady state equilibrium, when the mean number of births and deaths per unit time are equal,” researchers wrote. “This equilibrium point is a function of the birth and death rates, as well as the carrying capacity of the ecological system itself.”
“Since the birth and death rates are a-priori unbounded, we argue that this presents a fine-tuning problem.”
The search for extraterrestrial intelligence (SETI) has long captivated the human imagination, inspiring scientific inquiry and popular culture. However, Dr. Kipping and Dr. Lewis suggest that the odds of locating a technologically advanced alien civilization are much slimmer than previously thought.
In the study, researchers explored the Haldane prior probability distribution to estimate the uncertain quantity of alien life in the universe and the statistical likelihood of being able to detect an extraterrestrial intelligence.
Based on the math, researchers argue that the birth-to-death rate of any potential alien civilizations presents a significant challenge, potentially confining their existence to a narrow window of detectability.
The study also introduces a new perspective on the Drake Equation, a well-known formula developed to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy.
According to the researchers, the equation, while helpful in organizing our ignorance about the variables involved, may only partially account for the complexities of civilization emergence and extinction.
At the heart of Dr. Kipping and Dr. Lewis’ argument is the concept of the “birth-death” formalism, a simplified version of the Drake Equation that compresses its numerous variables into two primary factors: the rate at which civilizations emerge (birth rate) and the rate at which they vanish (death rate).
By examining these rates, the study suggests that the probability of a detectable civilization existing within our observational window is tied to the ratio of these birth and death rates.
The researchers argue that if civilizations’ death rates are high, meaning they tend to disappear relatively quickly, the chances of detecting one during its communicative phase are exceedingly low. “Most of Earth’s history lacks even multicellular life, let alone a technological civilization,” researchers note.
The study also touches on the concept of the “fine-tuning” problem, which posits that for SETI optimists to be correct in assuming a high probability of detecting alien civilizations, the universe must be finely tuned so that these civilizations exist in a delicate balance. However, the researchers caution against this optimism, pointing out that such fine-tuning seems unlikely given the vastness and variability of the cosmos.
In exploring this dilemma, the study introduces the idea of the “Steady State Drake (SSD) Equation,” which factors in the carrying capacity of the galaxy—essentially, the maximum number of civilizations it can support at any given time.
According to the SSD Equation, if the birth rate of civilizations is low and the death rate is high, the galaxy would likely have very few, if any, detectable civilizations at any moment.
“The growth curve is S-shaped, saturating at the carrying capacity for large birth-to-death rate ratios and tending to zero at the other end,” the study explains. “We argue that our astronomical observations appear inconsistent with a cosmos saturated with ETIs, and thus SETI optimists are left presuming that the true population is somewhere along the transitional part of this S-curve.”
In short, Dr. Kipping and Dr. Lewis say that the S-shaped growth curve of an extraterrestrial civilian means that unless we are fortunate enough to be looking during a period when many civilizations are simultaneously active, the probability of detecting them is extremely low.
This notion challenges the often optimistic view held by some in the scientific community that the universe is likely filled with intelligent life. While the study acknowledges the possibility of a “crowded” cosmos, it also emphasizes that current observations seem more consistent with a largely empty universe.
The researchers further address the so-called “Great Filter” hypothesis, which suggests that there may be a stage in the development of intelligent life that is extremely difficult to pass, thus explaining the apparent lack of extraterrestrial civilizations. Whether this filter lies behind us, making the emergence of intelligent life exceedingly rare, or ahead of us, representing a challenge that few civilizations can overcome, remains an open question.
The study also addresses the “zoo hypothesis,” a theory that postulates advanced extraterrestrial life may intentionally avoid detection or communication with Earth. Proponents of this theory suggest that aliens may avoid human contact for a variety of reasons, including to allow for natural evolution and sociocultural development or to avoid interplanetary contamination.
Citing prior research, Dr. Kipping and Dr. Lewis note that “maintaining a monolithic culture at galactic scales given the finite speed of causality makes such a scenario [the zoo hypothesis] highly contrived.”
Despite the sobering implications of their findings, the researchers advocate for the continuation of SETI efforts. They argue that even though the odds may be slim, the potential discovery of extraterrestrial intelligence would represent one of human history’s most profound scientific achievements.
“Although our conclusion casts doubt on the chances of a successful SETI program, we argue that SETI is an important and vital experiment that deserves dedicated resources,” the study concludes. “Whilst the odds of success appear small, such a success would arguably represent the most impactful scientific discovery in human history.”
Ultimately, this recent study serves as both a reality check and a call to action. It reminds us that searching for extraterrestrial intelligence may be fraught with challenges and uncertainties, it is a quest worth pursuing.
The universe may be vast and largely empty, but the possibility of finding another form of intelligent life, however remote, continues to inspire and drive scientific exploration.
In closing, Dr. Kipping and Dr. Lewis offer several ways to “salvage hope” in discovering an advanced extraterrestrial species. One method involves exploring the “Grabby Aliens” hypothesis and the weak anthropic principle.
First proposed by economist and futurist Dr. Robin Hanson, the “Grabby Aliens” hypothesis argues that extraterrestrial intelligence (ETI) rarely emerges. However, when it does, ETI often proceed to rapidly colonize and expand their sphere of influence on surrounding star systems.
In a 2021 paper published in The Astrophysical Journal, Dr. Hanson and a team of researchers used sophisticated computer modeling to predict that advanced “grabby” extraterrestrial civilizations evolve at a rate of roughly once per million galaxies. These alien civilizations expand and increase their volume at about half the speed of light, currently controlling 40%-50% of the universe, and each will eventually control 100,000 to 30 million galaxies.
According to the “Grabby Alien” hypothesis, we have yet to detect advanced extraterrestrials because, at only ⅓ the age of the universe, Earth exists in a pocket of space where ETI has yet to reach via the weak anthropic principle.
According to the models, Dr. Hanson and his colleagues say humanity shouldn’t expect to encounter the nearest “grabby aliens” or an advanced extraterrestrial intelligence until the next 200 million to 2 billion years.
“Once per million galaxies is very rare, and if ‘grabby aliens’ were the only kinds to see, then the chances for SETI to see any aliens nearby would be very low,” Dr. Hanson told Universe Today. “However, it may be that there are many times more ‘quiet’ alien civilizations out there. The higher the ratio of quiet to grabby alien civilizations, the closer might be the nearest quiet aliens to be found.”
While the ‘Grabby Alien’ hypothesis may not suggest imminent contact with advanced alien life, Dr. Kipping and Dr. Lewis say it does introduce a new and uncharted approach in the search for extraterrestrial intelligence.
“Such a scenario lends itself to inverting the normal view of SETI – rather than looking locally, we should be looking at regions greatly separated from us,” researchers wrote. “Such a hypothesis has the advantage that it is, in principle, verifiable via extragalactic SETI.”
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com