TL;DR: If intelligent, technological life exists anywhere in the galaxy, not only might it want to come here, but it likely would be able to come here, and potentially would come here. Unless we are the first civilization in the galaxy, this would imply it is rational to assume “they” could have already come here.

This post explains why it’s rational to believe “they” could come “here.”

Before getting started, I want to credit Isaac Arthur for doing the heavy lifting on the hard-science of the “crawlonizing” topic. While Isaac Arthur does not cover the UAP topic, this post uses much of his work on the hard-science of crawlonizing as the basis for the theory being applied to UAPs (by me). Isaac Arthur himself deserves huge credit for that work. For anyone interested in the crawlonizing topic I strongly suggest you watch the linked video of his. Isaac explains this topic far better than I could ever hope to. My post is long and confusing, but his video on “crawlonizing” is not. I encourage you to watch it. Cheers, Isaac.

PURPOSE OF THIS POST

Polling data suggests that most people believe that extra-terrestrial life is “out there,” but is not “here” (on Earth). Even Sean Kirkpatrick himself thinks this.

ABC News reporter: “Do you think extraterrestrial life is out there?”

Kirkpatrick: “I think it’s statistically unrealistic to think it isn’t”

Why “there,” but not “here?” The most common arguments for why “they” are not “here” consist of the following:

There is no other life anywhere else in the universe. We are unique. We are alone. If there is no life out “there,” there is no life to come “here.” Space is huge. The galaxy is huge. It would simply take too long to get “here.” No extra-terrestrial civilization will ever come “here,” even if “they” did exist and wanted to. It would take too long. Space is huge. The galaxy is huge. The technology that would allow traveling to another star does not exist, and will never exist, given how large space is. It’s not possible, even if the civilization wanted to do so.

These arguments are used to ridicule people who believe UAP may be present on Earth and are of extra-terrestrial origin. For example, this YouTube video yesterday used the “space is too big, it’d take too long, the distance is too far, and nothing could survive” arguments. This is small-minded thinking.

All of those debunk hypotheses are flawed and are addressed in this post. Humanity already possesses sufficient technology to colonize the entire galaxy if we really wanted to. I believe that if intelligent, technological life exists anywhere in the galaxy, not only might it want to come here, but it would likely be able to come here, and likely would come here. Unless we are the first civilization in the galaxy, this would imply they likely have already been here.

PART I: WHAT IS CRAWLONIZING THE GALAXY?

What is “crawlonizing” the galaxy?

“Crawlonizing the galaxy” refers to a hypothetical concept based in hard science regarding slowly colonizing the Milky Way galaxy. To do so, crawlonizing uses relatively slow-moving spacecraft, as opposed to the faster-than-light (FTL) travel often seen in science fiction and is common in UAP culture. This concept acknowledges the challenges and limitations of current and foreseeable future space technology, and is constrained by currently known physics.

Basically… “if we wanted to colonize the galaxy today, using current human technology, how could we actually do it?”

Key aspects of crawlonizing the galaxy include:

Slow Space Travel: Unlike the FTL spaceships in science fiction, crawlonizing involves spacecraft moving at speeds significantly lower than the speed of light, potentially around 0.1% to 1% of light speed. These ships would likely be generation ships, carrying multiple generations of humans over very long journeys. This type of space craft, including the propulsion methods used, are within our current understanding of physics and at worst within near reach of our current engineering capabilities. It would be realistic to assume humans could engineer such craft within the next 100 years or so given our knowledge today, and perhaps as early as “today” itself if we devoted significant resources to it. These craft are realistic to build given current human understanding of engineering and physics. Technological and Physical Constraints: Crawlonizing arises from the acknowledgment that known physics and technology may never allow for FTL travel. It also acknowledges that engineering may never reach the ability to produce craft that can travel at speeds approaching light speed, simply for practical, technological reasons. Issues like energy requirements, material durability, and the dangers of colliding with space debris at high speeds are significant challenges. As a result, crawlonizing assumes all space travel will remain relatively slow, indefinitely. Long Duration of Journeys: Travelling at such slow speeds means that reaching even the nearest stars would take multiple generations of human life times. A trip to a nearby star system could span hundreds or even thousands of years. As a result, “generation ships” would be built and staffed with humans who embark on multi-generational journeys to colonize the galaxy. Colonization Strategy: The colonization of the galaxy would proceed incrementally, with each colonized system potentially becoming a launch point for further colonization efforts. At each “hop” of the journey a colony would be established, and preferably new craft constructed for the next “hop.” A portion of the population staying at the colony and a portion of the population moving onto the next destination. Over millennia, human civilization could spread across the galaxy, despite the slow individual journey times. Alternative Methods of Speeding Up Travel: To optimize the rate of colonization, the concept includes using gravitational slingshot maneuvers around dense celestial objects like white dwarfs, red dwarfs, neutron stars or black holes to gain additional speed, and red giants to reduce speed at the opposite end of the journey. This could hasten the colonization process.

PART II: HOW DOES ONE CRAWLONIZE THE GALAXY?

Crawlonzing uses a variety of techniques to faciliate colonizing the galaxy. It’s likely not a “just use one of these” proposal. It’d be a “combine all of these for best results” theory.

The technology and techniques to best crawlonize the galaxy are described below.

Generation Ships: The standard method of crawlonizing the galaxy is utilizing “generation ships.” These are large space craft that would be manned by generations of humans, who embark from earth to colonize the galaxy. The original crew of the ship would not survive the journey, but their offspring would. Depending on the speed of the ship and the distance traveled, it may take many generations of humans aboard the ship to reach the destination. These ships could be powered by typical rocket propulsion systems (which would be very slow), some type of laser/solar sail system (faster), ion engines, or nuclear thrusters. All of these propulsion systems are within current human technological ability to build. Depending on the propulsion system used, the speed of the ship would reach somewhere between 0.1% – 1% of light speed. When a generation ship reaches its destination it would establish a colony at that location. Then, the colony would either build a new ship with a portion of the population staying at the colony and a portion of the population moving into the next destination, or not build a new ship and have a portion of the population continue onto the next destination in the current already-existing generation ship. However, building a new ship every colony “hop” is preferable, as this allows a fresh ship to be used for the next leg of the journey. Robotic Probes or Automated Colonization: This concept involves sending unmanned spacecraft equipped with AI and robotics to prepare or even start colonies before humans arrive. This requires advanced AI, robotics, and potentially self-replicating machines. The purpose of these probes could be to build habitats, mine resources, and continue replicating out across the galaxy. This concept is commonly referred to as “Von-Neumann probes” in UAP culture. What is interesting about this concept is that given the colonization is being done by an AI system time frames are not particularly relevant. A Von-Neumann probe is perfectly happy to navigate the galaxy at some tiny fraction of the speed of light. It does not care if it takes a million years to arrive it it’s destination as it will never die if properly engineered. This would also fit nicely any theory that the next phase of “evolution” is technological evolution, where the biological form of humanity is the biological on-ramp to humanity’s future as a techno species. NHI may already be techno species, and if so, this concept would easily apply to them. Utilizing Star Movement: Far more simple than an advanced propulsion system, it is possible to be clever about your colonization strategy using the natural gravitationally driven star movement within the galaxy to aid in colonization. Stars in a galaxy are not stationary. They orbit the galactic center, moving through space in complex paths influenced by the galaxy’s gravitational field and interactions with other stars and galactic structures. As stars orbit the galaxy, their paths can bring them relatively closer to or farther from each other over time. This movement can be used as an advantage in planning interstellar journeys. Over thousands or millions of years, the relative positions of stars change. A star system that is currently very far from Earth might come significantly closer in the future. Colonization efforts could target such stars, reducing the travel distance and time. With advanced astrophysics and computing, we can fairly accurately predict the future positions of stars. This allows for long-term planning of interstellar missions, selecting targets that will be in more favorable positions in the future. Additionally, by carefully timing a mission, a spacecraft could leave the Solar System when our Sun is moving closer to the target star, effectively reducing the journey time. This same strategy could be used on newly colonized star systems, creating an exponential rate of growth in colonization speed over time. The primary challenge for utilizing star movement for colonization is the immense timescales involved. The timescales required for significant changes in star positions are usually in the order of hundreds of thousands to millions of years. This is beyond typical current human planning capabilities, but could be relevant for a civilization committed to long-term galactic expansion. Gravitational Slingshots: Any or all of the above methods can be sped up when there’s the ability to utilize the gravity of large celestial bodies, like planets, stars, or even neutron stars or black holes, to gain additional velocity. In particular, interstellar black holes, and red giants are particularly useful to slingshot off of and can dramatically impact timing.

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Milky Way galaxy. Image credit: NASA.

PART III: HOW LONG WOULD CRAWLONIZING THE GALAXY TAKE?

Crawlonizing the entire galaxy would take a long time primarily due to the vast distances involved and the limitations of current and near-future propulsion technology. To determine an estimate for “how long” let’s consider a few key factors:

Speed of Spacecraft: The speed at which spacecraft can travel is a critical factor. Current and near-future technologies suggest possible speeds of 0.1% to a few percent of the speed of light. We will run calculations assuming potential spacecraft can travel at 0.1% light-speed, and 1% light-speed. Why pick this 0.1% number? The Parker Solar Probe, a probe launched by NASA in 2018, will reach a max speed of 191 km/s in 2025 on it’s current mission%20or%20191%20km/s%2C%20which%20is%200.064%25%20the%20speed%20of%20light). This is 0.064% of light speed, or already a bit more than half of our assumed number (0.1%). Therefore, being able to double the max speed of a 2018 mission seems within realistic reach using technology today, and therefore 0.1% of light speed is our starting point/lower bound for speed calculations. Size of the Milky Way Galaxy: The Milky Way galaxy has a diameter of about 100,000 light-years and a thickness of about 1,000 light-years in its denser parts. Time to Cross the Galaxy: Using plain old propulsion in a straight line at 0.1% light-speed it would take approximately 100 million years to cross the entire galaxy. At 1% light-speed it would take about 10 million years to cross the galaxy.

The calculations for these two speeds (note the notation of “c” as the speed of light) are as follows. This is beyond pessimistic, and assumes worst-case scenario/zero strategy for crossing the galaxy:

0.1% “c” craft: 100,000 LY / 0.001c = 100,000,000 years. 1.0% “c” craft: 100,000 LY / 0.01c = 10,000,000 years.

The Milky Way galaxy is estimated to be 13.6 billion years old, so being able to colonize the entire galaxy in 10-100 million years is already extremely reasonable, as even the upper 100 million year time frame only represents 0.7% of the age of the Milky Way and the 10 million year time frame represents only 0.07% of the age of the Milky Way. Therefore, if extraterrestrials existed anywhere in the galaxy more than 100 million years ago, and any of them felt like expanding, they already would have had sufficient time to get “here.” Depending on how old their civilization is it’s likely they have had enough times to get “here” many times over.

However, a clever colonization strategy would expand from multiple points – as previously mentioned, establish a colony, and then move onto one or more additional systems incrementally from there. Especially if one is particularly clever about where these initial colonies are established — and pick clever locations for initial “hub and spoke” locations, tremendous amounts of time could potentially be cut off. Initially, colonization would start from Earth, but as new colonies are established, they would become new points of departure, accelerating the process. This expansion wouldn’t be linear but more exponential, as each new colony could establish additional colonies.

Gravity-well slingshot maneuvers can cut tremendous amount of time off trip duration, especially near-proximity slingshot maneuvers around certain types of celestial objects. Picking initial “colonization hubs” that are near large numbers of useful celestial objects could dramatically reduce further travel times to “spokes” in a hub-and-spoke crawlonziation model.

It is possible to cut a lot of time off of the time to colonize the entire galaxy by sending multiple ships on long-range journeys initially in different directions, allowing them to get reasonably far apart, and then expanding out from those destinations. Given these ships are on initial long-range journeys they will have more possibilities to encounter celestial objects that could be useful for gravity-well assisted slingshot maneuvers along their path. By utilizing these gravity wells the speed of the craft could be increased to in significant excess of 1% the speed of light without needing any additional ship-based propulsion.

In particular, white dwarf stars are extremely common in the galaxy and are great to slingshot around. 97% of all stars in our galaxy will eventually become white dwarfs. It’s currently assumed there are 100 billion stars in the Milky Way, and it’s currently assumed that 10 billion of them are currently white dwarfs – so ~10% of stars are white dwarfs at the moment. White dwarfs are the most common type of “dead star,” and are typically about half a massive as our own sun. Most current white dwarfs come from stars that were originally more massive than our sun, and some white dwarfs are still more massive than our own sun (like Sirius B). But a white dwarf is usually only about 1% as wide as our own sun, and is only about 1,000th as bright. This means you can get a lot closer to a white dwarf than you can to our sun without getting your ship scorched. There are several white dwarfs stars within 20 light years of earth, so these could be immediately utilized at the beginning of the colonization journey to add tremendous amounts of speed.

Red dwarf stars are the most common type of star in the galaxy, with 73% of all stars in the Milky Way currently thought to be red dwarfs. They’re also quite good to use for gravity-well slingshot maneuvers, being much less bright per unit of mass than our own Sun. While not as optimal as white dwarfs, they’re still very useful, and given the majority of stars are red dwarfs any journey is certainly able to encounter some of these along the way. They’re everywhere.

Neutron stars are far more rare than white dwarfs, with about 1 billion total being in the galaxy (~1% of stars), and the nearest one we know of is 400 LY away. But neutron stars are even more dim than white dwarfs and are excellent to slingshot around if you have the opportunity to do so.

Black holes are considerably more rare, but NASA estimates there’s at least 100 million stellar mass black holes in the galaxy, perhaps more. Given these do not radiate at all, they could make excellent the best possible slingshot maneuver celestial objects, as stellar mass black holes are unlikely to be currently feeding and therefore would not have any accretion disks. They therefor would only emit hawking radiation, which would be basically zero, so you could get extremely close to the event horizon for a slingshot maneuver and gain tremendous speed.

Red giants can be useful for slowing the ship on the other end of the journey. Red giants are extremely “not dense,” and a ship could slant through upper layers of red giants to produce drag to slow a ship. Additionally, the ship could setup a large solar sail as it approached the red giant, and the red giant would slow the ship both via solar radiation and solar wind, which would be significant forces given the size of red giants. The same sail could drag through the red giants atmosphere resulting in significant slow down as well.

By utilizing gravity-well slingshot maneuvers around various types of celestial objects, as well as clever hub-and-spoke model expansion from celestially advantageous locations, it is reasonable to assume that travel times could be reduced as much as 10x. Why is this a reasonable assumption? None other than Freeman Dyson did some calculations on how fast you could get a craft moving using various types of gravity assists, and he even coined the term the “Dyson Slingshot.” His calculations demonstrated that you could gain 1% lightspeed on a single white dwarf binary slingshot, and gain 27% of lightspeed by using a neutron star binary gravity assist. Our previous assumptions were 0.1% to 1% of lightspeed, so even assuming a 10x speed up is only using ~1/3 of Dysons max/theoretical calculations.

Reducing the overall travel time by 10x, by using a hub-and-spoke model and gravity well slingshot maneuvers, could get the estimates of time required to colonize the entire galaxy down to a reasonable 10,000,000 years to 1,000,000 years. Again, I remind you the Milky Way is 13.6 billion years old – so enough time has passed for this entire galactic colonization to happen potentially 10,000+ times over.

PART IV: IS LIFE OUT THERE TO CRAWLONIZE THE GALAXY IN THE FIRST PLACE? IF SO, WOULD THEY EVEN CARE ABOUT COMING HERE?

As to the first question, “is there really extra-terrestrial life out there,” I think we all know the answer here: we don’t know (yet). If we did, /r/UFOs probably wouldn’t exist, or at least would be far less popular.

But scientists think there probably is, including Bill Nelson, the head of NASA.

“My personal opinion is that the universe is so big, and now, there are even theories that there might be other universes. If that’s the case, who am I to say that planet Earth is the only location of a life form that is civilized and organized like ours?” Nelson told Larry Sabato, a professor of politics at UVA. He continued: “Are there other planet Earths out there? I certainly think so, because the universe is so big.”

There are some tantalizing scientific leads though. Just to name a few:

JWST may have found Dimethyl Sulfide on K2-18B in September 2023 Venus may have phosphene in its clouds, which would be a strong signature of life TRAPPIST-1 is a candidate system for potential life Machine learning algorithms are surfacing new technosignature candidates in existing SETI datasets Tabby’s Star was at one point thought to be a Dyson sphere or some type of technological construction that was causing the dimming, and may still be NASA found a “Super Earth” in the habitable zone There’s some evidence life began before Earth existed New research suggests life in Venus’s clouds, despite the sulfuric acid

And there are more. JWST is helping us discover a lot, and it is rumored may have already discovered life and they’re just accumulating more data to be confident in the finding before publishing.

The second question, “If there is life out there, would they even care about coming here?” To answer this, let’s start with an assumption that something would need to attract “them” here. This would likely be a biosignature. This is the exact type of thing JWST is looking for on other exoplanets right now.

So the question is: how long ago would a biosignatures from Earth have been detectable? Fortunately there’s been some research on this. Researchers estimate, using our current technology (JWST), that slam-dunk Earth biosignatures would have been detectable from an exo-planet in our own galaxy approximately 1 billion years ago. “Indicative biosignatures,” suggesting “life is probably here, but can’t be 100% sure,” were probably detectable as many as 3-4 billion years ago. The chart below lays out these timelines.

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Detectability of biosignatures over time, from https://arxiv.org/pdf/1802.09367

Note, so no less than 1 billion years ago another planet somewhere in our galaxy could have detected our biosignatures, and potentially as long as 3-4 billion years ago. With the constraints of “it takes 1 to 100 million years to get here” as we calculated above, this allows plenty of time for an extra-terrestrial civilization to reach Earth to study us if they were so inclined.

But would they be so inclined to come here?

We can’t know for sure. But the “Copernican principle” or “cosmological principal” states that humans are not special — we’re not in any type of privileged position in the universe. So let’s assume that human curiosity, desire to explore, etc., is not special, and any extraterrestrial civilization may have at least some members of their population with similar traits. It’s worth noting that entire extraterrestrial civilization does not need to be interested in such pursuits, just like most of humanity is not interested in exploring space themselves. All it takes is one, or a small subset, similar to how NASA is interested, or the various billionaire funded space companies are interested. If any subset of the civilization is interested in exploration, that’s sufficient to suggest that they will explore, and it seems unreasonable to assume all members of all extraterrestrial civilizations would not explore.

Nonetheless, using humanity as an example for what “typical” may look like:

Humanity is interested in learning more about our universe, as is evidenced by NASA existing, the various probes and observatories we build, and the science programs we operate to do so. Humanity is particularly interested in observing other life forms, as evidenced by looking for biosignatures, such as the DMS found on K2-18b. There are many scientific projects looking for life in the universe. Humanity is already discovering potential exoplanet biosignatures with our current technology (JWST). We need to increase confidence in these signatures over time by collecting further data, and improving our technology to better observe such data. Humanity is building probes that could reach 20% light speed for the purposes of long-distance high-fidelity observation data. If a high confidence signature of life is discovered on an exoplanet, it’s already been proposed that we send such a probe to that planet to gather more data.

Therefore, at least for humanity, we can see that we’re: interested in learning whether life exists elsewhere, build technology to try to determine that, and if we find it, already are openly discussing sending technology there to learn more about the life.

Using the “Copernican principle,” it’s reasonable to assume that at least some portion of an extra-terrestrial civilization may feel similarly, and would want to come here (themselves, or at least a probe with some of their technology) if they detected biosignatures of life on Earth, in order to learn more about us.

So yes – if life exists out “there,” it’s reasonable to assume “they” would want to come “here,” and given we already are building the technology required to send probes to other stars ourselves, it’s reasonable to assume they would come here.

PART V: IS THERE ANY HARD-SCIENCE EVIDENCE OF AN EXTRA-TERRESTRIAL CIVILIZATION CRAWLONIZING THE GALAXY?

You already know the short answer to this: No.

However, the long answer is more complicated, and can be summarized with a “maybe.“

The immediate question debunkers will ask is “If extra-terrestrials have colonized the entire galaxy how come we don’t observe them? Wouldn’t SETI see them immediately?” The answer to this is actually… probably not. SETI has given many a false sense that we have a fantastic ability to detect life in extra-terrestrial systems. We don’t. As this study highlights, SETI has searched just 0.00000000000000058% of a “cosmic-haystack” for the proverbial needle.

SETI is deeply flawed in their search ability. SETI’s maximum range is about 300 light years for any signal, regardless of strength, so the signal would have to be extremely close to us to detect at all. SETI for most of it’s history has also assumed that extraterrestrial civilizations will use radio spectrum, and even worse, at known frequencies (the hydrogen band), which are two giant assumptions. They miss almost all the spectrum out there. SETI would require an extra-terrestrial species to come and smack us in the face with a signal from basically our own cosmic front porch in order for them to detect it at all. The lack of any techno-signatures observed by SETI therefore should not deter anyone from thinking life is out “there” somewhere. SETI has basically done nothing to determine if life is truly out there.

Other studies have looked for Dyson spheres around stars and found no evidence of such spheres. Compelling, but again makes giant assumptions about technology. While it’s currently thought that Dyson spheres are a fantastic and “obvious” power source, it’s possible that fusion power (real and already built, just not economical), or antimatter (real and already created/captured at CERN, just not economically), or black hole engines (real, possible, and fit with currently know physics, but never built yet by humans), or something else entirely not thought of yet by humanity makes Dyson spheres worthless and never pursued by extraterrestrials. Therefore, the lack of observed Dysons should not be a sign that life is not out there.

Finally, NASA is currently looking for biological exo-signatures… signs of life on other world. They do this by using JWST to observe the atmosphere of planets as they cross in front of the star of the system. They break that passes through the atmosphere up into a spectrum, and based on bands in the spectrum can determine which chemicals are in the atmosphere. JWST has been functional for only a handful of years and this is already leading to some potential positive results. DMS on K2-12b for example. And there are rumors of other not-yet-public results that may become public soon. So, this is a strong “maybe” that at least some biological life is out there.

Nonetheless, if an extraterrestrial civilization has colonized most or all of the galaxy already, shouldn’t we detect it everywhere (biological exo-signatures) this way? Perhaps, but maybe not. As previously mentioned there’s a large body of scientists and researchers who think that a bio species is not the most well suited for space travel, and that a techno species is far more well suited for such exploration. Think robots, AI, self-replicating machines, etc. It’s quite likely that an extra-terrestrial civilization would send primarily some type of techno-species out to colonize the galaxy, leaving the biological components of that species at home. In that case the techno species may produce zero detectable biosignatures at all, even if they were on the star right next to our own. Therefore, the lack of life biomarkers cannot be definitive in making the statement “there’s no ‘life’ out there” if we include a techno-species as “life.”

But is there any hard-science evidence that “they” have come “HERE?” Maybe.

Remember what was said earlier about a self-replicating ship that would explore the galaxy, colonizing as it went along? We may have observed something like that. Oumuamua. Avi Loeb, a professor at Harvard, thinks it may have been exactly this type of object. In particular, the object also sped up as it left the solar system, faster than could be explained by normal natural means. This could be evidence of some type of solar sail or propulsion as it left the system, as have previously been described in the crawlonizing best practices.

So yeah, Oumuamua would actually kind of fit with what we’d expect to see for some type of crawlonizing probe. So… maybe.

PART VI: CONCLUSION

Since that was a giant wall of rambling text, let’s circle back. There are some arguments as to why “they” could never come “here.” Let’s lay them out again with direct retorts:

There’s no life out there: While we have not yet directly observed life, we have strong leads, and likely will discover some soon. Most scientists agree it’s probably out there. See K2-18b for reference. It would take too long to get here: This is small minded thinking, and as shown above, it wouldn’t. There’s been plenty of time for a species to get here if so inclined. Yes, the time span would exceed that of a single biological organisms life-span, but may not for a techno-species, or if the species is biological they could utilize generation ships. There’s potentially been enough time since the Milky Way was created for a craft to have made ~13,600 trips across the galaxy. The technology required to get to another star will never exist, it’s too far: This is not true. The propulsion systems already exist, and we have the current technology to build such a craft, we just never have had the motivation to do so. It’d be very expensive, but it is doable today.

The final piece of all this is the age of humanity. The Milky Way is 13.6 billion years old. Given how new humanity is, it’s likely any extraterrestrial civilization is older than us. In order to not be older than us they’d have to be less than 50,000 years old. Given the Milky Way is 13.6 billion years old, it’s almost guaranteed that any extraterrestrial civilization will be older than our own.

Humanity has been a civilization for less than 50,000 years, a technological civilization for less than 5,000 years, and a space-faring civilization for less than 100 years. We’re comparatively new here. Given our rate of exploration and expansion we likely will be expanding into our planetary system sometime this decade, and potentially beginning the process or expanding into the stars also this decade and no later than next decade.

Again, back to probabilities here… it’s probable that any extraterrestrial civilization is much older than us. Probably even a billion+ years older than us (there’s about a 92% chance, just given the number of years passing, that they would have formed sometime earlier than the most recent billion years, just by the distribution of years since the formation of the Milky Way). Given what we’ve laid out about how they probably would want to and could come here, with that amount of time, being that much older than us, they would have had plenty of time to do so. Which (to me) implies that if “they” are out there, “they” probably have already been “here.”

So, that’s it. I’m not saying “they” are “here” now. I’m just saying it’s not entirely insane to think that “they” could come “here” if “they” wanted to, and may have already been here already. So next time someone calls you nuts for thinking anyone could explore the entire galaxy, you can tell them we already have the tech to do it, we just don’t have the desire.

That’s a wrap folks! If you made it this far through the post: well done.

I want to re-iterate, I recognize this post is gigantic and not the most clear. I strongly advise anyone interested in this to watch Isaac Arthur’s video “Crawlonizing The Galaxy: Settling Space At Ultra-Low Speeds.” He’s much better at explaining things than I am, and does a much better job explaining Crawlonizing. If you’re at all interested, it’s worth a watch.