Astrobiology & The Search For Life

Astrobiology animated. Source: AP GURU

Astrobiology is the study of life that occurs somewhere other than Earth, as we’ve learned in class, and this blog post emphasizes its developments and possible future directions. There have been substantial scientific, technological, and programmatic advances achieved in the hunt for extraterrestrial life since the 2015 publication of NASA’s Astrobiology Strategy. Understanding the beginnings and evolution of life requires interdisciplinary collaboration and a systems-level approach, which are required by astrobiology.

First, it’s crucial to comprehend the concept of dynamic habitability, which stresses how habitability is a continuum that changes across time and space as a result of planetary and environmental evolution. Research into Earth’s past as well as the coevolution of life and its environment is necessary in order to comprehend Earth’s habitability and find potential biosignatures. It is suggested that NASA and other organizations promote multidisciplinary research on dynamic habitability and coevolution. The understanding of extreme life on Earth and how it interacts with the environment has made some significant strides. It is important to comprehend how life can adapt to harsh settings and if subterranean habitats are habitable since this knowledge has consequences for the hunt for life outside in our solar system, notably on Mars and ocean worlds. As a result, NASA is concentrating on investigating and learning more about subterranean habitability.

Last but not least, it’s critical to understand the environments where potentially habitable exoplanets emerged and developed (particularly how stellar and planetary dynamics coevolved). In order to comprehend planetary habitability, comparative planetology between the solar system and exoplanetary systems is seen to be a highly effective strategy. Astrobiology research will increasingly use techniques including theoretical modeling, statistical analysis, and artificial intelligence. Overall, there has been rapid progress and exciting prospects in the field of astrobiology, emphasizing the need for interdisciplinary collaboration, systems-level thinking, and the exploration of diverse environments within and beyond our solar system.

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Blog 7 – The Fermi Paradox

When learning astronomy, one often wonders if humanity is alone in the galaxy. Physicist Enrico Fermi pondered this question, and ultimately came to a rather profound conclusion. Statistically our galaxy should be home to at least a handful of advanced societies more than capable of interstellar travel, so why have we not encountered any? Fermi assessed that, since the galaxy is billions of years old, sophisticated civilizations have had ample time to not only greatly surpass our technological standing, but also to potentially explore and populate the galaxy. Although it would take millions upon millions of years to colonize a decent amount of solar systems in the galaxy, this period of time is nothing when compared to the colossal age of the galaxy. Fermi, stumped at this revelation, wondered where such intelligent civilizations were and why we have not met any.

Many answers have been proposed to the Fermi Paradox. Perhaps, even with advanced space travel capabilities, intelligent societies may have no interest in prolonged exploration since space travel takes so long and/or is too costly. In addition, space colonization would surely be a draining task both physically and mentally. Maybe sophisticated life, understandably, doesn’t have the stamina to colonize the galaxy, or even parts of it. But the most mind-boggling thought is that maybe intelligent life is purposefully avoiding us. What if our solar system is a “zoo” from which other, more advanced societies can observe us for data. Regardless, the Fermi Paradox is both a fascinating and relevant topic relevant to our understanding of out galaxy.

For more information, see this Youtube Video on why the Fermi Paradox is important.

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Asteroid Mining

Hayabusa: A robotic spacecraft by JAXA to acquire a sample from the asteroid Itokawa

Asteroid mining can be crucial in helping us to acquire rare materials in our solar system. The asteroid belt has 8% metal-rich asteroids and 75% volatile-rich carbonaceous asteroids.  Currently the technique is mainly just theoretical as we don’t have the infrastructure yet to properly bring these asteroids into earth’s orbit. A solution for this is to start building bases in lunar or earth’s orbit that have ease of access to the asteroid belt so that we can begin bringing them into our orbit. It is predicted that it would cost 2.6$ billion dollars to bring an asteroid back to Earth and that an asteroid that is very platinum rich could contain upwards of 25 billion dollars’ worth of platinum. Possibly when technology has advanced to the point where robots could conduct these missions to mine asteroids autonomously so that there is no human risk this could be a very realistic mining method. Currently though it is completely unfeasible as the risks and costs are too high if failure does occur, and scientists suggest that we work on practical technology.

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How Extremophiles Work

Water bears, tiny invertebrates that live in coastal waters and freshwater habitats. Source: Science Photo Library

As we talked about in class a few weeks ago, Extremophiles are living things that flourish under challenging conditions.They are amazing because they can endure situations that would be fatal to the majority of other life forms. They originate from Archaea, Eubacteria, and Eukarya, the three branches of the three-domain categorization scheme. Extremophiles have caused scientists to reevaluate the beginnings of life on Earth since they have been discovered in conditions that were formerly thought to be hostile. Endoliths are a type of extremophile that lives deep below and may consume inorganic rock materials or absorb nutrients from rock veins. According to the specific extreme settings they live in, such as acidophiles (acidic environments), alkaliphiles (alkaline environments), and thermophiles (high temperatures), extremeophiles have also been characterized.

Extremophiles

Extremophiles have sparked debate on the viability of extraterrestrial life. Scientists seek to learn more about the conditions that may support life in alien locations by researching extremophiles. They may live in severe conditions, including those with high pressure, radiation, acidity, temperature swings, salinity, a lack of water and oxygen, and even contaminants and poisons left over from human activity. It may be possible to learn something about the potential habitability of other planets and moons by studying how extremophiles survive and thrive in these harsh environments.

Categorization

The categorization of extremophiles is explained using a variety of systems, including the three-domain and five-kingdom systems. The Carl Woese three-domain approach classifies organisms according to their genetic makeup. Woese classified archaea as a separate realm made up of ancient species that frequently display extremophile traits. The other domains are eukarya (organisms with a nucleus) and eubacteria (real bacteria). These categorization schemes aid in the better understanding of the distinctive traits that distinguish extremophiles from other species.

Conditions

There are various harsh conditions in which extremophiles flourish. Some examples include Lake Untersee in Antarctica, which has a pH that is strongly alkaline and is rich in methane, simulating circumstances that may occur on other planetary bodies. The human stomach and other extremely acidic ecosystems are home to acidophiles, which enjoy acidic surroundings. Extremophiles that require an alkaline pH to exist, like Spirochaeta americana, can be found in alkaline habitats, such California’s Mono Lake. Extremophiles can also be found in geysers, hydrothermal vents, and regions that are polluted with acids and heavy metals.

Conclusion

In conclusion, extremophiles are creatures that live in harsh settings and have pushed the boundaries of what we think is possible for life. They have repercussions for the beginnings of life on Earth and the potential for life elsewhere in the universe. Extremophiles originate from a variety of fields and have amazing adaptations to thrive in harsh environments. Scientists seek to learn more about the possible habitability of different settings and broaden their understanding of the potential for life in the cosmos by researching extremophiles.

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The Fermi Paradox

A possible solution to the Fermi Paradox?

The Fermi Paradox attempts to answer the question about extraterrestrial life that so many humans have thought about for centuries. Enrico Fermi a physicist, in 1950, while discussing extraterrestrial life he began to wonder if aliens did in fact exist then how have they not expanded throughout the galaxy and showed signs to us today. He came to this conclusion by realizing that the universe is billions of years old, so intelligent life has had plenty of time to showcase their presence to the galaxy. Thus, he began to ask the question, where are the they? which is the Fermi Paradox. Since then, scientists have debated Fermi’s theories and come up with different arguments to attempt to prove him wrong. One of these arguments is that perhaps interstellar travel is too costly and that it is not worth it for aliens to travel to places within our vision. Another argument is that they are so far separated from us in the grand scale of the universe that it could be billions more years until they could reach us or where we have the technology to see where they have already reached. After learning about all of these different ideas I tend to side against Fermi as the universe is just way too large to make conclusions that aliens do not exist because we haven’t been able to see them yet.

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The History and Future of the Universe: A Time Scale

If you’d like to feel the crushing weight of existential dread as we approach the end of this course, and for me, the end of my time at Vanderbilt, I have just the video for you! It’s a YouTube video called “Age of Universe: Time in Perspective,” and it uses a time-to-volume comparison in order to relate known volumes to the amount of time it takes for certain events to occur. I think this video is insanely cool and I’d like to recap some of the most notable events!

The video starts by defining its scale: 1 second of time is equivalent to a 1 mm3 cube. 1 minute is 60 mm3, 1 hour is 3600 mm3, etc. The video then zooms in to demonstrate the time scales of very brief things in relation to very small things. However, I find this more intuitively difficult to picture–I have the perception that I can understand how large the Earth is (even though I really can’t) better than I can understand the size of a virus, so I’m just going to skip to the part of the video that covers larger and larger lengths of time!

1 second and 1 minute on the established time-volume scale. Source

On our scale, a week-sized cube (604.8 cm3) is about on par with a can of coke. A century-sized cube (3.15 m3) is about the height of a human being. A 10,000 year-sized cube (315.5 m3) is a bit wider than a four door sedan, and is also how long ago the last glacial period occurred. 

A person in relation to 1 century. Source

As we continue to zoom out, New York City becomes visible in the background of the video. We first see it at 252 million years (7,950,000 m3), which is how long ago the Mesozoic Era (the Age of Reptiles) began. By 4.54 billion years (0.143 km3), which is how long ago the Earth formed, the cube is covering a few blocks of NYC. We then reach 13.8 billion years (0.43 km3), the age of the universe, while covering some more blocks of NYC.

The time since the formation of the Sun and the age of the universe in relation to NYC. Source

The craziest thing to me is that this doesn’t seem all that large. Yes, we started from a millimeter cube, but we’re not even to the size of an entire city yet and we’ve already encompassed the history of the entire universe. We’re also only a third of the way into the YouTube video–that’s how you know things are about to get crazy.

Set to a much more ominous soundtrack, we enter a new section of the video: the future of the universe. This involves a lot of estimations, since these events obviously have not occurred yet! Only a bit larger than the age of the universe is a 22 billion year-sized cube (0.69 km3) representing the universe’s age when it ends via the Big Rip scenario, in which the accelerating expansion of the universe tears apart all the matter in the universe, and even spacetime itself. For the rest of the video, we assume that the Big Rip scenario does not occur. Taking up a sizable chunk of NYC is a 1×1013-year sized cube (315 km3), the estimated lifetime of red dwarfs. At 1×1014 years (3,150 km3), we have the transition from the Stelliferous (star-dominated) Era to the Degenerate (dwarf, neutron star, and black hole-dominated) Era, and most of NYC is covered. At 1×1015 years (31,500 km3), all the planets in star systems will separate from their orbits, and the Sun will have cooled to 5 K. All of NYC is engulfed.

The lifetime of red dwarfs and the transition between two of the five eras of the universe in relation to NYC. Source

Things start to speed up here. At 1×1020 years (3,100,000,000 km3), our cube covers half the continental United States, and the Earth will collide with the theoretical black dwarf Sun if it has not already been engulfed by the Sun during the Sun’s red giant phase. At 1×1023 years (3.1×1012 km3), our cube is a bit larger than Earth, which marks when most stellar remnants and other objects are ejected from the remains of their galactic cluster. 2×1036 years (6.3×1025 km3) is the estimated time for all nucleons in the observable universe to decay, and our cube is the size of Mars’ orbit. Yes, that indeed escalated quickly.

The time for all nucleons in the observable universe to decay in relation to Mars’ orbit. Source

We must leave our Solar System for the remaining comparisons. 3×1043 years (9.4×1032 km3) marks the high end for the estimated time for all nucleons in the observable universe to decay, marking the beginning of the Black Hole Era. Our cube is on par with the size of TON 618, the most massive black hole currently known. Our next cube doesn’t come for quite some time. 2×1066 years (6.3×1055 km3) is the estimated time until a black hole of 1 solar mass completely decays into subatomic particles via Hawking radiation, and the cube is many times larger than the Andromeda Galaxy. 

The high estimate for the time for all nucleons in the observable universe to decay in relation to TON 618. Source

Some more zooming out and we’re at the size of the Observable Universe. This is deeply unsettling, considering we’re still only two thirds of the way through the video. After this point, our scale really doesn’t help us anymore, since we’re already way beyond anything we can remotely imagine, or even fool ourselves into imagining, since we’ve lost any kind of reference point. Thus, I won’t go into detail here, but some stuff is still pretty neat.

The Observable Universe. Source

At 6×1099 years (1.89×1089 km3), the supermassive black hole TON 618 is estimated to dissipate via Hawking radiation. Around here is the beginning of the Dark Era. We fast forward to 1×101500 years, which is when all baryonic matter is estimated to have fused to form hypothetical iron stars, assuming protons do not decay. We then get to the completely absurd estimate for the time until iron stars collapse via quantum tunneling into black holes, 10^(10^26) years. This is so long that I couldn’t figure out how to get WordPress to do nested exponents. It is also so long that this number written in non-exponent form in a straight line would extend many millions of light years. We’re still going, though–10^(10^120) years is the highest estimate for the time for the universe to reach its final energy state. 10^(10^(10^56)) years is the statistical length of time for quantum tunneling to generate new inflation events, potentially resulting in new Big Bangs. 

We finally reach the end of this horrifyingly exciting video, and I don’t know about you, but I’m happy to not be immortal. It’s unfortunate to think about humanity’s future accomplishments that we won’t be around to see, but I am very glad to not have to witness the Earth collide with a black dwarf Sun, or sit and wait around for the ridiculously long and relatively boring Black Hole Era to be over. How does this video, or my description of it, make you feel? Do you think that this could be how our universe was created–from the quantum tunneling of another extremely old universe? If you like this type of video, I would also recommend this similar video, called “Timelapse of the Future: A Journey to the End of Time.” Happy watching!

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Dragonfly: Quadcopter on Titan

After the recent rocket launch in preparation for the Artemis mission, I decided to look into the other space exploration projects currently underway. One that stuck out to me is the Dragonfly mission. After the landing of Huygens, a space probe sent from Cassini, in 2005, astronomers have desired a more advanced exploration of Titan. Evidence currently points to a subterranean ocean existing below the surface, and this could have huge implications for the survival of humans elsewhere in the solar system. Titan also has dunes, mountains, lakes, and rivers that are methane based instead of water. Study of these features could tell us about non-water based geological processes. Titan’s current atmosphere also resembles Earth’s early atmosphere which could help us better understand Earth’s development.

Dragonfly is unique compared to other rovers because it is actually a quadcopter. Because Titan’s atmosphere is about 50% denser than Earth’s meaning it is dense enough for flight (unlike Mars) but not so dense it will crush the rover. The low gravity also means flight is more fuel efficient than on Earth. This means Dragonfly will explore an area of Titan and fly up to 10 kilometers to the next site to collect more data. The battery will then charge over the course of one Titan day (16 Earth days) to gain enough power for the next flight. After this mission we will have a thorough map of some of Titan’s surface including areas not easily accessible with a land rover like mountains. Learn more about Dragonfly here.

Source: NASA/JOHNS HOPKINS APL/STEVE GRIBBEN/MAGDA SAINA

The current launch window is scheduled for June 2027 with an arrival to Titan in 2034. Although this is still far out, I am excited for the new information we will gain about Titan, Earth, and the development of quadcopter based rovers.

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Could We Even Communicate With Aliens If We Found Them?

After learning about the Golden Record, Arecibo message, and other ways astronomers have attempted to communicate with extraterrestrial life (if it is out there), I can’t help but think this outreach is very limited to civilizations that communicate in exactly the same way as we do. This seems unlikely to me, given the extreme diversity in communication of species limited to Earth. For example, octopuses, which are widely considered one of the most intelligent animal species, communicate through gestures and changing skin color. Others communicate through smells, dances, calls, and more that we cannot even decipher. Even as humans, we speak in a very limited range of frequencies, and our written language is completely arbitrary to our own cultures. 

The odds of an alien species existing, wanting to contact us, and then being able to understand us are incredibly slim. Again the analogy of an alien species wanting to communicate with ants (us) rings true. Then, assuming we found a way to communicate, our understanding of the universe through math and physics might be completely foreign to them. This reminds me of the movie Arrival where ideas such as quantum physics and string theory are incredibly simple, but our concepts of basic math like addition and algebra are very difficult. Although this situation is not super scientific, and the movie takes a lot of creative liberties, it does provoke thought about communication with extraterrestrials. Perhaps the probability to have the ability to communicate in a similar and meaningful way with other possible civilizations should be another variable in the Drake or Seager Equations.

Alien communication from Arrival. Source: Paramount Pictures

Some astronomers are currently working on ways to make communication with extraterrestrials possible, and it revolves largely around AI. Machine learning techniques are already being implemented at the University of Toronto to sift through data collected over the past several years and determine whether we missed evidence of extraterrestrial communication. The AI has already output 8 “signals of interest” based on its initial algorithm, and through fine tuning the algorithm, the AI should only become more accurate. Learn more about this research here.

As we have all seen the rise of AI in recent months, perhaps it is the key to not only recognizing extraterrestrial communication but also work as a sort of translator between civilizations. After recognizing patterns in the other civilizations’ communication, it could likely come up with translation for humans to understand. Or another possibility is that the AI becomes so much more intelligent than us that this alien civilization decides it is worth communicating with the AI instead of us.

Much is yet to be seen, but the rapid and continuing development of AI could be the key in the search for and eventual communication with extraterrestrial life.

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What’s Next?

While I’ve always been vaguely interested in astronomy, before taking this class some part of my brain assumed we had somewhat stagnated on space exploration. This is largely because I knew other stars and galaxies were so far away, and we just don’t have the technology to travel to them.

Ultimately, this class helped me realize how much we’ve learned about our own Solar System in the past decades, and how much we have yet to find out and explore. So, I’m going to use this blog post to talk about some of the future Solar System exploration planned.

A rendering of the Europa Clipper, currently being built by NASA.

NASA alone is planning further exploration of the Moon, Mars, and Europa in the next few years. The Artemis missions to the Moon have the ultimate goal of helping us learn what we need to know to send the first astronauts to Mars: the farthest any human has ever been from Earth. The Europa Clipper, currently being built by NASA, will help us learn more about the icy moon.

However, NASA is far from the only entity looking into space exploration. Some companies, like SpaceX, are looking to commercialize space. As mentioned in my previous blog post, the European Space Agency just launched a mission to explore the Jovian moons. Space is becoming more and more accessible, and as opposed to the Space Race of the 1960s, world powers are working together to explore and make progress. I’m excited to see what the future will hold!

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Where Are All the Aliens? Potential Solutions to the Fermi Paradox

In class, Dr. G mentioned a Wait But Why article about the Fermi Paradox. I absolutely love this article and the entire concept of the Fermi Paradox–I even wrote about it in my Common App essay four years ago! The Fermi Paradox, first informally presented by physicist Enrico Fermi, describes the apparent contradiction between our extremely high estimations of the number of Earth-like planets in our universe and the utter lack of evidence of any extraterrestrial life. A number of possible solutions that explain the Fermi Paradox have been put forth, and I’d like to discuss some of them here.

First, a bit of background on the numbers: there are about 100-400 billion stars in our galaxy. The conservative estimate for the percentage of stars that are sun-like is 5%. Used in conjunction with the conservative estimate of 100 billion stars in the galaxy, we get 5 billion sun-like stars. The conservative estimate for the percentage of sun-like stars with Earth-like planets is 22%. Used in conjunction with 5 billion sun-like stars, we get 1 billion Earth-like planets. Any further breakdowns related to the prevalence of life, specifically intelligent life, is speculative, so we’ll just leave it at a ridiculously high estimate of 1 billion Earth-like planets in the Milky Way.

If even a fraction of these planets have life, and a fraction of that life is intelligent and attempting to communicate through broadcasting radio waves or laser beams, would we not expect the SETI (Search for Extraterrestrial Intelligence) satellite dish array to pick up some kind of signal? And yet–nothing. Where are all the aliens?

The SETI satellite dish array. Source

Before getting into the possible solutions, there is an important concept to be familiar with–the Kardashev Scale. The Kardashev Scale describes three types of intelligent civilizations: Type I, Type II, and Type III. Type I Civilizations have the ability to harness all of the energy that reaches their planet from their parent star. We’re not quite there–humans are considered a Type 0.7 Civilization. Type II Civilizations have the ability to harness all the energy of their host star. An example of this would be building a Dyson Sphere–a massive spherical shell around the star, allowing all of the star’s energy output to be absorbed by the sphere and used by the civilization. Type III Civilizations have the ability to harness all the energy of their home galaxy. For example, colonizing the entire galaxy, and perhaps building Dyson Spheres around every star you find.

Diagram showing a Dyson Sphere with a radius of 1 AU. The entire interior surface of the shell would be in the Sun’s habitable zone, allowing humans to live on its entire interior surface area. Source

Now, let’s brainstorm some possible solutions. There are two major groups of solutions: 1) We don’t see signs of Type II and III Civilizations because there are no higher civilizations, and 2) There are Type II and III Civilizations out there, but there are logical reasons why we don’t see signs of them.

Solution Group 1: There aren’t any Type II/III Civilizations

Integral to solution group 1 is the Great Filter–some stage along the spectrum of pre-life to Type III Civilization that is either impossible or extremely unlikely to progress beyond. Think of it as a barrier that almost no species can leap over. The thing is, we don’t know where the Great Filter is, especially in relation to our current status as a Type 0.7 Civilization. Different potential Great Filters lead to some different potential solutions.

Diagram explaining the Great Filter. Source
Solution 1.1: The Great Filter is behind us

The first solution is that the Great Filter is behind us. Even with the extremely high number of Earth-like planets, there could be some barrier that is just so near-insurmountable that we’re extremely rare. For example, perhaps it is so astronomically improbable for life to originate out of non-life that it almost never happens. If we’re not the only ones past the Great Filter, we’re one of the very few. This bodes well for our future, but is a bit sad and lonely.

Diagram showing our place on the spectrum if the Great Filter is behind us. Source
Solution 1.2: The Great Filter is ahead of us

The second solution is that the Great Filter is ahead of us. Perhaps it is quite common for life to originate and become multicellular and develop cities and society, but something else keeps them from attaining Type II/III status and communicating with other lifeforms. For example, perhaps it is impossible to have enough time to invent interstellar travel before being wiped out by the gamma-ray bursts that inevitably occur in the galaxy every so often. This one is decidedly less fun for us–we will eventually hit the Great Filter, and it is statistically unlikely that we will cross it.

Diagram showing our place on the spectrum if the Great Filter is ahead of us. Source

Solution Group 2: There are Type II/III Civilizations, but they aren’t communicating with us

This is where the fun begins, and we can really be creative! The Wait But Why article lists ten possible solutions that I will explain.

Solution 2.1: Intelligent life came to Earth before humans evolved

Recall the cosmic calendar. If the Big Bang occurred at midnight on January 1st, anatomically modern humans evolved at 11:52 pm on December 31st, and the entirety of modern history (considered the past 437.5 years) occurred in the last one second. What if an intelligent species visited Earth before we were around (perhaps even before many animals were around), decided there wasn’t anything very interesting going on here, and left? We would have no way to know.

The cosmic calendar. Source
Solution 2.2: We live in the outskirts of a colonized galaxy

Similar to the last solution, perhaps an intelligent civilization has colonized the more dense regions of our galaxy, but we live in some desolate rural area that they decided isn’t really worth the trouble. We are indeed ⅔ of the way from the center of the Milky Way–this is basically the suburbs and might not be of interest.

Solution 2.3: Why colonize in the first place?

Also similar to the last solution, perhaps it really isn’t worth it to colonize the entire galaxy. It takes a lot of effort, a lot of material, and a long time–once you’ve got one Dyson Sphere, is another one, multiple light-years away, really going to do you a lot of good? Perhaps intelligent civilizations decide to set up a paradise within their own star system, and decide not to explore the cold, largely empty galaxy. One extension of this is that perhaps the entire physical realm is seen as boring and mundane and inconvenient–perhaps it’s more fun to download your brain into a virtual reality simulator, allowing you to escape the limitations of the physical body and play Minecraft for all eternity.

Solution 2.4: It’s a bad idea to broadcast your location

I thought about this when we discussed the Golden Records and the Arecibo message in class–perhaps it is not a very good idea to tell the entire galaxy where we live, just in case someone violent is listening? Perhaps all other intelligent species have caught onto this as well, which would explain the total utter lack of signals received by SETI satellites. Yikes!

Solution 2.5: Super-predator civilizations quash all competition 

If there isn’t a Great Filter, or the Great Filter is ahead of us, then there’s probably a decent amount of life out there. Someone had to be first, and considering how late we came along in the cosmic calendar, I wouldn’t bet money that it’s us. Whoever evolved first would very likely become the most advanced first, and would have the advantage over all other civilizations. What if they’re warlike? Perhaps they realized that it’s quite inefficient to exterminate all other life in the galaxy, but as soon as anyone gets close to becoming a threat, they strike. This would not bode well for us.

Solution 2.6: Our listening technology isn’t very good

The Wait But Why article uses a walkie-talkie analogy to explain this: if you walked into an office building and turned on a walkie-talkie, you would hear nothing. You might conclude that there’s no one in the building, since you didn’t hear anyone talking. In reality, it’s just that no one uses walkie talkies! What if we point our satellites in the sky and listen for all the wrong signals with all the wrong technology? Furthermore, perhaps communication exists on widely different scales for different life forms. In the second The Lord of the Rings movie, the Ent species speaks very slowly–it takes hours to greet everyone “good morning.” What if an alien species took years to say “hello”? We would perceive only white noise.

Solution 2.7: The government is hiding things

Perhaps we have received, or are receiving, contact from intelligent life, but the governments of the world are keeping it quiet to prevent mass panic. Time will tell!

Solution 2.8: We live in a zoo

In Star Trek, the “Prime Directive” prohibits super-intelligent beings from making contact with less developed species, since this would artificially alter their progression. Perhaps we haven’t reached the necessary level of intelligence to be invited into the club yet. Or, maybe in our colonized Milky Way, our solar system is seen as a National Park of sorts, meant to be admired from afar but never touched, lest it be soiled.

Solution 2.9: We’re too primitive to perceive the higher civilizations all around us

I think this one is fun. Theoretical physicist Michio Kaku put forth an analogy using ants and superhighways to explain the apparent lack of aliens. He said “Let’s say we have an anthill in the middle of the forest. And right next to the anthill, they’re building a ten-lane super-highway. And the question is, ‘Would the ants be able to understand what a ten-lane super-highway is? Would the ants be able to understand the technology and the intentions of the beings building the highway next to them?’” If human beings are ants, there could be a super-intelligent civilization within sight, perhaps even with us on Earth, and we wouldn’t even know it. We wouldn’t be able to comprehend what they are or what they’re doing, since their existence would be so utterly beyond us. We would be totally irrelevant to them as well–have you ever stopped walking in order to try to talk to ants?

Solution 2.10: Reality is not what it seems

Perhaps everything we know is fake. What if Earth and humanity are a science experiment set up by super-intelligent beings, or the universe is really a hologram, or we are the Sims in an intelligent being’s video game. Who knows?!


I have a very hard time making my mind up about what I think is true, as well as what I want to be true. Overall, I think it’s safer for humanity if the Great Filter is behind us, and we’re either the only intelligent life out there or at least the first. However, this is sad and lonely–it’s certainly exciting to discover types of planets in other star systems that we don’t have in ours and speculate about the kind of life that could live there, and it’s neat to learn about all the different extremophiles that thrive in insane environments. I also oscillate on what I actually think is true–the Fermi Paradox is called a paradox for a reason! I’m inclined to lean toward us being the only life in the galaxy. Scientists haven’t been able to create life in a lab, making me think that the Great Filter is the extreme improbability of life originating in the first place. 

What do you think? Do you think there is life in our galaxy? Intelligent life? If there’s a Great Filter, what do you think it is? Do you have other possible solutions to the Fermi Paradox to put forth? Thank you for reading!

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