Tag: astrophysics

THE LOOMING GREAT FILTER

On By AlessandraIn Extrasolar Planets, S.E.T.I., Sci-FiLeave a comment

What Is The Great Filter?

Imagine the vastness of the universe, filled with billions of galaxies, each containing billions of stars, many of which have planets orbiting them. It seems statistically probable that life, even intelligent life, should have arisen elsewhere. This is the core of the Fermi Paradox, named after physicist Enrico Fermi, who famously asked, “Where is everybody?” If the universe is so conducive to life, why haven’t we detected any signs of extraterrestrial civilizations?

The Great Filter offers one potential answer to this paradox. It posits that some “filter” – a significant hurdle or barrier – prevents most, if not all, potential life from reaching a stage where it becomes easily detectable to us. This filter acts as a bottleneck in the timeline of life’s development.

Economist Robin Hanson introduced the Great Filter hypothesis, which suggests that a nearly insurmountable barrier prevents most civilizations from advancing to an interstellar presence.

Think of it like a race with many potential starting points (the formation of habitable planets) and a finish line (becoming a technologically advanced, space-faring civilization). The fact that we don’t see many (or any) other finishers suggests that there’s a difficult obstacle somewhere along the track that most participants fail to overcome. This obstacle is the Great Filter.

The big question is: Have we passed the filter, or is it still ahead of us?

Where is the Great Filter?

The crucial question then becomes: Where does this filter lie?

There are a few possibilities:

The Filter is in Our Past:

This would mean that the difficult step(s) required for life to arise and evolve into intelligence are behind us. The origin of life (abiogenesis), the development of complex multicellular life (like eukaryotes), or the emergence of intelligence are sporadic events that occurred on Earth. If this is the case, we are fortunate, and the universe mainly lacks other advanced civilizations. This scenario can be exciting (we are exceptional!) and terrifying (we are alone).  

Implication for us: If we discover simple life on Mars or Europa, it suggests that the Great Filter is ahead of us, which is a bad sign.

Our prospects might be bright because we’ve already cleared the primary bottleneck. We might be one of the first, if not the only, intelligent species to reach this stage in our part of the galaxy (or even the universe). This could mean that our potential for growth and expansion is immense, relatively unconstrained by the factors that halt most other potential civilizations. However, it also places a significant responsibility on us, as we might be the custodians of intelligence in our corner of the cosmos.

Implication for SETI: The lack of detected extraterrestrial intelligence would be less surprising. It would suggest that we shouldn’t expect to find many other advanced civilizations because the odds of reaching this stage are so low. A “silent sky” would be consistent with a filter in our past.

The Filter is in Our Present:

This suggests a critical hurdle we are facing or are about to face that will prevent most civilizations from surviving or becoming detectable. This is something like unsustainable technological development leading to self-destruction (e.g., nuclear war, climate catastrophe, biological warfare) or some unknown cosmic threat that advanced civilizations inevitably face. This is a particularly worrisome scenario, implying that our survival is far from guaranteed.

Implication for us: If we are close to interstellar travel but don’t see others who have made it, we are doomed to self-destruction.

This would suggest that there’s a high probability that we, like many other potential civilizations before us, will not make it through the current stage. The challenges we face today, such as climate change, the risk of nuclear war, or the potential to misuse advanced technologies, could be manifestations of this filter. Our immediate priority would be to identify and overcome these threats to ensure our long-term survival.

Implication for SETI: The silence we observe could be caused by most civilizations’ self-destruction or stalling at a similar stage of development. Detecting advanced extraterrestrial intelligence would be rare because such civilizations are inherently short-lived. If we detect one, they might have found a way to navigate the “present” filter, offering us hope and potential lessons.

The Filter is in Our Future:

This implies that the significant challenges for developing advanced civilizations still lie ahead of us. There are fundamental limitations to interstellar travel, or maybe advanced civilizations inevitably collapse for reasons we can’t yet comprehend. This scenario suggests that while life arises relatively often, it rarely progresses to a truly advanced and detectable stage.

In essence, the Great Filter tries to reconcile the clear likelihood of extraterrestrial life with its observed absence by suggesting that some stage in the development of life is far more improbable than it seems. Identifying where this filter lies has profound implications for understanding our place in the universe and our future.  

Implication for us: If no one has expanded across the galaxy, they couldn’t, and neither can we.

Our present achievements might be less unique than in the “filter in our past” scenario. However, it would mean we still have a significant, yet-to-be-encountered hurdle to overcome. Understanding the nature of this future filter would be crucial for our long-term prospects. Perhaps it’s a physical limitation of the universe or an intrinsic sociological or technological barrier that all advanced species eventually face.

Implication for SETI: We might expect that the universe could have harbored many now-extinct or stalled civilizations that never made it past this future filter. Detecting signs of life or even less advanced civilizations might be more likely than detecting truly advanced, space-faring ones. A “silent sky” regarding advanced signals could still be consistent with a universe where life and even rudimentary intelligence are not uncommon.

Arguments for and against the Great Filter


Arguments FOR the Great Filter Being in Our Past:

  1. The Complexity of Abiogenesis: The leap from non-living matter to a self-replicating, evolving organism is incredibly complex. We still don’t fully understand how it happened on Earth, and the conditions required might have been particular and rare.
  2. The Eukaryotic Transition: The development of eukaryotic cells was a fundamental step in the evolution of complex life. This occurred only once in the history of life on Earth and involved a symbiotic event that might be highly improbable.
  3. The Cambrian Explosion: The rapid diversification of multicellular life during the Cambrian period suggests that the conditions and evolutionary pathways leading to such complexity might be unusual.
  4. The Uniqueness of Human-Level Intelligence: While evolution favors traits aiding survival, the specific suite of cognitive abilities that led to human intelligence, including abstract thought, language, and advanced tool use, might be a rare evolutionary outcome.
  5. The “Hard Steps” Argument: Proponents argue that there are likely one or more “hard steps” in the development of life that are statistically very unlikely, and one of these occurred in our past.

Arguments AGAINST:

  1. The Prevalence of Building Blocks: Organic molecules, the precursors to life, seem common in the universe (e.g., found in meteorites and interstellar clouds). This suggests that the raw materials for life are readily available.
  2. Early Appearance of Life on Earth: Life appeared relatively quickly after the planet cooled down enough to support it. This might suggest that abiogenesis is relatively easy under the right conditions.
  3. Convergent Evolution: The independent evolution of similar traits in different lineages (e.g., eyes, wings) suggests that specific biological solutions are favored and might arise relatively frequently when conditions are right. This could argue against the uniqueness of some evolutionary steps.
  4. Our Limited Understanding: Our current understanding of abiogenesis and early evolution is incomplete. We might be underestimating the likelihood of these events occurring elsewhere.

Arguments FOR the Great Filter Being in Our Present:

  1. Observable Self-Destructive Tendencies: Humanity faces significant challenges like climate change, nuclear proliferation, and the potential to misuse powerful technologies. These could represent the kinds of self-inflicted wounds that might plague other advanced civilizations.
  2. The Lack of Kardashev Type II or III Civilizations: If advanced civilizations routinely overcome their initial technological hurdles, we might expect to see evidence of civilizations that can harness the energy of their entire star (Type II) or galaxy (Type III). The absence of such clear evidence could suggest a bottleneck at the “Type I” stage (a civilization that can harness all the energy available on its planet).
  3. Historical Precedents of Civilizational Collapse: Numerous civilizations have risen and fallen on Earth. While not due to interstellar travel limitations, these collapses highlight the fragility of complex societies.

Arguments AGAINST:

  1. Humanity’s Increasing Awareness and Mitigation Efforts: We are increasingly aware of the threats we face and are (slowly) taking steps to mitigate them. This suggests that self-destruction might not be inevitable.
  2. The Potential for Technological Solutions: Future technologies might solve existential threats, such as advanced climate engineering, asteroid defense systems, or safer energy sources.
  3. The Vastness of Space and Time: Even if civilizations self-destruct, they might do so at different times and ways, making it challenging to observe this “present” filter on a cosmic scale. Brief windows of detectability might be missed.
  4. The Possibility of Transcendence: Advanced civilizations might find ways to transcend their physical limitations or move beyond planetary dependence, thus avoiding self-destruction.

Arguments FOR the Great Filter Being in Our Future:

  1. Fundamental Physical Limits: There might be insurmountable physical barriers to interstellar travel or communication (e.g., the speed of light, energy requirements, and the vast distances involved).
  2. Unforeseen Universal Threats: Catastrophic cosmic events that we cannot currently predict or defend against might be common and act as a filter for even advanced civilizations.
  3. Intrinsic Limits to Societal Complexity or Longevity: Perhaps advanced civilizations inevitably reach a point of stagnation, lose the drive to expand, or face internal contradictions that lead to their decline over very long timescales.
  4. The “Great Silence” Itself: The lack of compelling evidence for advanced extraterrestrial civilizations could be seen as indirect evidence for a future filter that prevents most from becoming truly widespread and detectable.

Arguments AGAINST:

  1. Our Limited Understanding of Future Physics and Technology: We cannot definitively predict what future breakthroughs might be possible. Technologies we can’t even imagine might overcome current limitations.
  2. The Potential for Artificial Intelligence and Self-Replication: Advanced AI could potentially overcome the limitations of biological life for interstellar travel and colonization. Self-replicating probes could spread throughout the Galaxy.
  3. The Time Scales Involved: The universe is vast and old. Perhaps we haven’t been around long enough to witness the emergence of truly advanced galaxy-spanning civilizations, or they are too far away for their signals to have reached us yet.
  4. The “Zoo Hypothesis” or Other Explanations for Silence: There might be non-filter reasons for the apparent lack of contact (e.g., advanced civilizations are deliberately avoiding us, or our search methods are inadequate).

Considering these arguments helps to illustrate the complexity and uncertainty surrounding the Great Filter and its potential location. Each scenario has implications and challenges our understanding of life in the universe.

Discoveries Relevant To The Discussion of The Great Filter

The Origin of Life (Abiogenesis):

  1. RNA World Hypothesis Support: Recent research continues to strengthen the “RNA world” hypothesis, which suggests that RNA, not DNA, was the primary form of genetic material in early life. RNA can store genetic information and catalyze chemical reactions, making it a plausible candidate for the foundation of life. Discoveries of RNA’s catalytic abilities and its presence in various environments bolster the idea that the building blocks of life could have formed relatively easily. This might suggest that the origin of life, while still mysterious, might not be as improbable as once thought, potentially weakening the argument for abiogenesis as a major Great Filter.
  2. Protocell Research: Scientists are making progress in creating artificial protocells—simple, cell-like structures. Some recent experiments have even shown protocells capable of reproduction. These advances help us understand how cell membranes and basic cellular processes could have arisen from non-living matter. If these steps can be replicated in the lab, it might imply that the transition from chemistry to biology isn’t as difficult, making abiogenesis less of a filter.
  3. Deep Sea Hydrothermal Vents: Recent discoveries about microbial life thriving in extreme environments, such as deep-sea hydrothermal vents, suggest that life can emerge and persist in conditions very different from those on Earth’s surface. This expands the range of environments where life might be possible, suggesting that the origin of life might not be as constrained by specific planetary conditions.

The Development of Complex Life:

  1. Early Evidence of Complex Life: Some studies have suggested that complex life may have appeared on Earth much earlier. For example, some have interpreted discoveries of ancient fossils in places like the Franceville Basin in Gabon as evidence of early multicellular organisms. If complex life emerged relatively early in Earth’s history, it might indicate that this transition is not as tricky or rare as the Great Filter hypothesis might suggest.
  2. Asgard Archaea: The discovery of Asgard archaea, a group of microorganisms with genes that are strikingly similar to those found in eukaryotes (the complex cells that make up multicellular organisms), is providing insights into the evolutionary transition from simple to complex cells. These findings suggest a more gradual and potentially less improbable pathway for the evolution of eukaryotic cells, a key step in developing complex life.
  3. Genetic Complexity: Advances in genomics reveal the complex genetic changes necessary for the evolution of multicellularity. While these changes are significant, their existence suggests that the evolution of complexity is possible given enough time and the right conditions.

The Emergence of Technology:

  1. Exoplanet Discoveries: The discovery of thousands of exoplanets, including many in the habitable zones of their stars, suggests that Earth-like planets are abundant in the universe. This increases the probability that other planets could have developed life, though it doesn’t directly address the likelihood of that life becoming technological. However, more habitable planets mean more chances for life to get started.
  2. Artificial Intelligence (AI) Research: The rapid advancement of AI raises questions about the potential for machine intelligence to either facilitate or hinder the development of advanced civilizations. On one hand, AI could help a civilization overcome some of the challenges of interstellar travel or resource management. On the other hand, some theories suggest that AI could pose an existential threat, potentially acting as a Great Filter. Some scientists, like Michael Garrett, have theorized that the development of Artificial Superintelligence (ASI) could be a Great Filter, potentially leading to the extinction of civilizations before they can make contact.

Final Considerations:

  • Sample Size of One: It’s crucial to remember that our understanding of life’s origins and evolution is based on a sample size of one: Earth. This makes it difficult to extrapolate to the rest of the universe.
  • Ongoing Research: Astrobiology, genomics, and paleontology are constantly evolving. Future discoveries could significantly change our understanding of the likelihood of various life development stages.

THE MYSTERY OF PROJECT SERPO

On By AlessandraIn Aliens and Alien Abductions, Extrasolar Planets, Sci-Fi, U.F.O.s

Alien Exchange Program or Modern Myth?

In the 1960s, an extraordinary claim surfaced that would forever alter how we view human-alien contact. Project Serpo, an alleged secret exchange program between the U.S. government and extraterrestrials from the Zeta Reticuli star system, promised to unlock the truth about UFOs and alien life. According to the story, 12 human astronauts—ten men and two women—traveled across 39 light-years aboard an alien spacecraft to a distant planet called Serpo. The journey took only a few months, defying our current understanding of space travel. Years later, only a few returned, leaving behind a trail of unanswered questions. But is there any truth to this incredible tale, or is it just another conspiracy theory?

The Origins of Project Serpo: Fact or Fiction?

Project Serpo entered the public consciousness in 2005 through a series of mysterious emails posted on a UFO email list moderated by a former U.S. government employee, Victor Martinez. The anonymous whistleblower claimed to be a retired Defense Intelligence Agency (DIA) official, revealing top-secret information about the alleged exchange program. According to the story, the program began after the notorious Roswell Incident of 1947, where a surviving alien allegedly helped facilitate future human contact with their species—the Ebens from Serpo.

The mission supposedly launched in 1965, and astronauts spent 13 Earth years (but only 10 Serpo years) living on the alien planet. They studied the Ebens’ culture, language, and technology. However, the mission’s success was marred by tragedy: two astronauts died on Serpo, two chose to stay behind, and only a handful returned to Earth.

Fig:1: Planet Serpo’s twin suns.

Yet, despite the dramatic narrative, there is no verifiable evidence to back the story. The source of the emails remains anonymous, and no official government documents have surfaced to confirm any such mission. The lack of physical evidence has led many to dismiss the entire claim as a fictional or highly elaborate conspiracy theory.

Breaking the Light Barrier: Is FTL Travel Possible?

One of the most intriguing aspects of Project Serpo is the claim that the astronauts traveled to Serpo in a mere nine months, despite the planet being 39 light-years away. According to current scientific understanding, this is impossible. According to Einstein’s theory of relativity, nothing can travel faster than the speed of light.

However, some theoretical physicists have speculated about methods allowing faster-than-light (FTL) travel, such as the Alcubierre Drive, which involves bending space-time around a spacecraft. 

Even if these ideas hold theoretical promise, we are far from being able to develop such technology, and no evidence suggests that this capability exists in the hands of extraterrestrials—or that it was used during Project Serpo.

Interstellar Travel: The Reality of Reaching Other Worlds

While interstellar travel remains a cornerstone of science fiction, reaching distant star systems is increasingly becoming a topic of serious scientific discussion. The discovery of exoplanets in habitable zones around stars like Zeta Reticuli raises the possibility that life could exist on other planets. However, current space travel technology (such as chemical rockets or ion drives) remains too slow for a light-year journey. Until propulsion or space-time manipulation breakthroughs occur, travel to such distant places remains beyond our grasp.

One key component of UFO lore is that alien civilizations might have already conquered these technological barriers. If true, this would challenge humanity’s understanding of space, time, and even the limits of human potential.

The Secret History of UFOs and Alien Contact

Project Serpo connects directly to the broader theme of UFO disclosure and the long-standing belief that governments have hidden the truth about extraterrestrial encounters. For decades, UFO enthusiasts have argued that official secrecy, such as the U.S. government’s Project Blue Book and later, the Advanced Aerospace Threat Identification Program (AATIP), has intentionally suppressed evidence of alien encounters.

The idea of a secret human-alien exchange program fits within the context of this narrative. UFO whistleblowers and conspiracy theorists have long claimed that alien contact has already happened, but the details are kept from the public to prevent widespread panic or societal disruption. In some versions of the cover-up narrative, Project Serpo is said to be part of a larger plan to prepare humanity for eventual open contact with extraterrestrials—whether by revealing fragments of information or hiding them for “national security” reasons.

Project Serpo: A Tale of Hidden Knowledge?

While there is no solid evidence to prove the existence of Project Serpo, the idea of hidden alien contact taps into a broader theme of concealed knowledge that has existed for centuries. Just as secret societies and ancient civilizations have been linked to supposed hidden knowledge of extraterrestrial visitors, Project Serpo aligns with the notion that humanity may have already been part of extraterrestrial events but is kept in the dark. This idea of hidden history stretches beyond UFOs and connects to broader questions about humanity’s place in the universe and the true nature of reality.

Could there be a grand cosmic secret that powerful governments or organizations have hidden from the public? Is it possible that space exploration, alien encounters, and unexplained phenomena are part of a more profound mystery that is too complex or dangerous for humanity to understand?

Conclusion: Fact, Fiction, or a Step Toward Disclosure?

Fig.2: An Eben village on planet Serpo where two human astronauts chose to remain.

Project Serpo remains one of the most bizarre and controversial stories in the realm of UFO research. While there is no scientific proof to support its existence, the elements of the story—alien exchange programs, secret missions, and faster-than-light travel—raise important questions about the future of interstellar travel, UFO disclosure, and hidden history.

As we uncover more about exoplanets, advanced propulsion technologies, and the search for extraterrestrial life, the line between science fiction and science fact will likely blur even further. Whether Project Serpo is just a well-crafted myth or a glimpse into a hidden history remains to be seen—but it certainly serves as a thought-provoking piece in the ongoing puzzle of humanity’s relationship with the stars.

THE PLANETARY ZOO

On By AlessandraIn Aliens and Alien Abductions, Extrasolar Planets, S.E.T.I., Sci-Fi

Introduction

The Zoo Hypothesis is a fascinating explanation for the Fermi Paradox—the mystery of why we see no signs of alien civilizations despite the vastness of the universe. It suggests that advanced extraterrestrials deliberately avoidcontactwith Earth, treating us like a species in a cosmic wildlife reserve or a simulation experiment.

Origins of the Zoo Hypothesis

  • It was proposed in 1973 by John A. Ball, an MIT radio astronomer.
  • The idea: If highly advanced civilizations exist, they may intentionally hide from us to allow us to develop naturally—just as humans observe animals in a zoo without interfering.

Why Would Aliens Hide from Us?

1. We Are Too Primitive

  1. Earth might be home to a young, unevolved species.
  2. Advanced civilizations may wait for us to reach a specific technological or ethical maturity level before revealing themselves.
  3. If they contact us too early, it could disrupt our natural progress, similar to how humans enforce non-contact policies with uncontacted tribes on Earth.

2. We Are in a Cosmic Experiment

  1. Earth could be a scientific observation zone where aliens study the evolution of intelligence.
  2. If this is true, our development could be closely monitored, but direct interference is forbidden to maintain an unbiased result.
  3. Could our rapid technological advancements (nuclear power, AI, space travel) trigger “First Contact” protocols?

3. Self-Imposed Alien Secrecy (“Galactic Prime Directive”)

  1. Just as Star Trek’s Prime Directive forbids interference with less advanced civilizations, aliens may have an ethical rule against disturbing primitive species.
  2. Perhaps all intelligent civilizations agree to avoid contact until a species reaches interstellar capability.

4. We Are Being Quarantined

  1. Instead of protecting us, aliens might be protecting themselves from us.
  2. Humanity is still violent and unpredictable, so advanced civilizations may see us as dangerous.
  3. They might be waiting for us to prove we can act responsibly on a cosmic scale.

Possible Evidence for the Zoo Hypothesis

  1. The Great Silence – Despite decades of SETI (Search for Extraterrestrial Intelligence), we have found no clear alien signals. If civilizations are avoiding contact, this makes sense.
  2. The Wow! Signal (1977) – A mysterious radio signal from space that has never been explained. Could it have been a brief “ping“ from an alien observer?
  3. UFO/UAP Phenomena – Some suggest that Unidentified Aerial Phenomena (UAPs) are signs of covert alien monitoring, though this remains speculative.

Could We Break Out of the Cosmic Zoo?

If we are in a “zoo“, how could we force aliens to acknowledge us? Possible strategies:

  1. Sending Powerful Signals – Intentionally transmitting loud radio signals or laser pulses to attract attention (METI – Messaging to Extraterrestrial Intelligence).
  2. Interstellar Expansion – Once we leave Earth and colonize space, it may trigger “first contact“.
  3. Developing Advanced AI or Post-Human Intelligence – If we create superintelligence, it might meet the criteria for alien civilizations to engage with us.

Are We Alone or Just Being Watched?

The Zoo Hypothesis remains speculative, but it’s one of the most intriguing solutions to the Fermi Paradox. If true, it means that there is plenty of life in the universe—but for now, we are being observed until we prove ourselves worthy of joining the greater galactic community.

ARE ROGUE WORLDS THE ULTIMATE ABODE FOR LIFE?

On By AlessandraIn Extrasolar Planets, S.E.T.I.1 Comment

The search for extraterrestrial life has captivated humanity for centuries. Countless questions arise in our quest to discover if we are alone in the vast universe. The Drake Equation, a mathematical formula introduced by astronomer Frank Drake in 1961, attempts to estimate the number of civilizations within our Milky Way Galaxy. However, recent scientific discoveries have unveiled a new intriguing possibility – rogue worlds. These wandering bodies, expelled from their original solar systems, may hold the potential for harboring life. In this blog post, we will explore the fascinating intersection of the Drake Equation and the enigmatic realm of rogue worlds, exploring the tantalizing notion of life beyond our home planet.

The original form of the equation is the following:

N = R* f(p) n(e) f(i) f(l) f (c) L

• N is the number of civilizations trying to communicate with us right now;

• R* is the rate of star formation in stars per year;

• f(p) is the fraction of those stars which have planetary systems;

• n(e) is the number of Goldilocks (i.e., Earth-type) planets in a planetary system);

• f(l) is the fraction of habitable planets that are inhabited;

• f(i) is the fraction of inhabited planets that possess intelligent technological civilizations;

• f (c) is the fraction of intelligent technological civilizations that choose to emit detectable signals;

• L is the length of time signals will be sent.

The first three factors are astronomical, the fourth and fifth are biological, and the last two factors are social. There are several issues with the equation. Among these:

(1) The uncertainties are large enough for the astronomical factors and increase as one progresses from the astronomical to the biological to the social.

(2) Most factors depend on theoretical insights of star and planet formation, new discoveries about exoplanets, and varying subjective opinions on the evolution of life and intelligence. The presumed longevity of civilization must also be taken into account.

(3) The equation has many hidden assumptions: a uniform star formation rate (SFR) over the Galaxy’s lifetime and a steady state of civilization birth and death. 

(4) No matter what value one chooses for R*, the assumption is always that a habitable planet must have a star. However, rogue worlds (bodies that have been thrown out of their own nascent solar system) wander around the Galaxy unattached to a star.

This last item has recently awakened great interest in the scientific community.

Theoretical calculations (Imagined Life, by James S. Trefil and Michael Summers, 2019) suggest that:

“[…] the number of rogues might be between twice and thousands of times the number of conventional planets. Interstellar space must be littered with them!”

Also, rogue planets need not be uninteresting ice balls with no life and energy. Lacking direct radiation from a star, a world can be heated by the residual power from its formation and the radioactive decay of elements in its interior. If provided with one or more moons, the planet can draw energy from a process known as tidal heating (which is responsible for the subsurface oceans on some of Jupiter and Saturn’s moons).

All in all, rogue planets can be compared to (Imagined Life by James S. Trefil and Michael Summers, 2019):

“[…] houses whose lights have been turned off but whose furnaces are still operating.”

Interestingly, rogue planets had been predicted as early as the 1930s by American horror and S.F. author Howard Phillips Lovecraft.

In his short story: The Haunter of the Dark, he wrote:

“[…] remember Yuggoth, and more distant Shaggai, and the ultimate void of the black planets… […].”

When the planet Pluto had just been discovered by Clyde Tombaugh (1906-97) at Lowell Observatory (Flagstaff, Arizona), he wrote another short story: The Whisperer in Darkness.

Here are a few quotes: 

“[…] Their main immediate abode is a still undiscovered and almost lightless planet at the very edge of our solar system – beyond Neptune and the ninth in distance from the [S]un. It is, as we have inferred, the object mystically hinted at as ‘Yuggoth’ in certain ancient and forbidden writings; […] I would not be surprised if astronomers become sufficiently sensitive to these thought-currents to discover Yuggoth when the Outer Ones wish them to do so. But Yuggoth, of course, is only the stepping-stone. The main body of the beings inhabits strangely organised abysses wholly beyond the utmost reach of any human imagination.”

And also:

“[…] Those wild hills are surely the outpost of a frightful cosmic race – as I doubt all the less since reading that a new ninth planet has been glimpsed beyond Neptune, just as those influences had said it would be glimpsed. Astronomers, with a hideous appropriateness they little suspect, have named this thing ‘Pluto.’ I feel, beyond question, that it is nothing less than nighted Yuggoth […].”

What would life be like on a rogue planet?

According to Imagined Life, by J.S. Trefil and M. Summers:

“It’s dark. Not midnight-on-a-side-street dark, but trapped-in-a-cave dark. And no wonder—there’s no sun in the sky, for this is a rogue world, one that circles no star. There is a moon up there somewhere, but without a source of light for it to reflect, it’s just a darker patch in the sky. Whatever life forms live on this planet had better be able to see in infrared because there’s simply no other light to be had. You’re wearing infrared sensors, fortunately, and you spot a few of these creatures scurrying back to the planet’s subterranean tunnels, where they can bask in the heat emanating from the planet’s interior. […]”

Life on a dark planet has been described by British author Arthur C. Clarke in his 1950 short story: A Walk in the Dark:

“[…] Here at the edge of the Galaxy, the stars were so few and scattered that their light was negligible. […]” 

“[…] Here at this outpost of the Universe, the sky held perhaps a hundred faintly gleaming points of light, as useless as the five ridiculous moons on which no one had ever bothered to land. […]” 

“[…] No one could deny that the tunnels out in the wasteland were rather puzzling, but everyone believed them to be volcanic vents. Though, of course, life often crept into such places. With a shudder, he remembered the giant polyps that had snared the first explorers of Vargon III […]

The Drake Equation is not meant to give a precise answer but to stimulate scientific discussion and exploration. It is based on several factors that affect the likelihood of finding intelligent life, such as the rate of star formation, the fraction of stars with planets, the fraction of planets suitable for life, and the fraction of civilizations that develop radio technology. Each factor is multiplied by the previous one, resulting in the number of detectable civilizations in our galaxy. However, many of these factors are uncertain, and different assumptions can lead to different outcomes. For example, some estimates suggest that there could be millions of civilizations in our Galaxy, while others suggest that we might be the only one.

According to a recent study, under the strictest set of assumptions, where life forms between 4.5 billion and 5.5 billion years after star formation, there are likely between four and 211 civilizations in the Milky Way today capable of communicating with others, with 36 the most likely figure. Another study yielded two main results: an optimistic one and a pessimistic one. In the optimistic situation, the researchers suggested the aforementioned 42,777 communicating extraterrestrial intelligent civilizations (CETIs) with an error margin of plus 267 and minus 369, and they would need to survive 2,000 years on average to communicate with us.

The Drake Equation is a fascinating way to explore the possibilities of extraterrestrial life and communication. It helps us understand what we know and don’t know about our place in the universe. It also inspires us to keep searching for signs of other civilizations and to wonder what they might be like.

Read more about this topic in this post and this other post.