I really want this but for Azure Devops. If you're not familiar, Microsoft owns both Github and Azure Devops, and both do similar: git repos and project management. I can use Github Copilot, Claude Code CLI, etc. against code on my disk, including Azure Devops MCP. But what I can't easily do is like Github Copilot Agent and apparently this Claude Code on Web: Assign a ticket to @SomeAi and have a PR show up in a few minutes. Can't change to github for _reasons_.
Would love any suggestions if anyone in a similar story.
This could mean in the Drake equation ne -number of planets capable of life- is very small. A planet has to be hit with a comet big enough to deliver a large amount of water but not so big or fast to destroy it. And be in the Goldilocks zone of the star. Also the mass of the planet would play a part - gravity of more massive ones would be more likely to capture a comet. But again, too massive and I could see that hampering life.
The Drake Equation is filled with assumptions, like life must appear on a planet in the Goldilocks zone of a star. The whole equation has only one datapoint to extrapolate from. Tweak the equation's parameters and it will predict universes that only have one civilization per galaxy or worse! We have no way of knowing what those parameters are because we haven't seen other examples.
A major reason we are interested in Europa is because it might have underground oceans. Hypothetically, through tidal forces with Jupiter, the moon's core is hot enough to create oceans under the ice crust. Combined with hydrothermal vents you have the possibility for deep sea life similar to our own deep oceans. The Drake Equation does not predict this possibility.
The equation itself makes no assumptions. But anyone trying to calculate something with it must.
The last five factors in the equation will be filled in by assumptions based entirely on one data point, life on Earth. From your link:
ne = the average number of planets that can potentially support life per star that has planets.
fl = the fraction of planets that could support life that actually develop life at some point.
fi = the fraction of planets with life that go on to develop intelligent life (civilizations).
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
L = the length of time for which such civilizations release detectable signals into space.
Can you define any one of those without assumptions, in a scientifically proven way?
One approach is to give each variable a probability distribution. The greater our uncertainty about possible values, the wider the bell curve.
Drexler and colleagues did that, and found "a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively). ’Where are they?’ — probably extremely far away, and quite possibly beyond the cosmological horizon and forever unreachable."
A probability distribution describes how likely different outcomes are.
It requires multiple observations or an assumed model that can represent variability.
Which is why they set very wide ranges on the things we know little about. Doing that is less unjustified than guessing specific values, as people have usually done.
It's nowhere near a precise estimate of the probability of life. What it mainly shows is that the Fermi "paradox" is no such thing. It can look that way if we guess specific parameter values, but if we fully account for our uncertainty on the various parameters, then the result is a decent chance that we are alone, given the knowledge we have so far.
I’m not saying precise. I’m saying it isn’t even an estimate.
You can’t have a distribution with one data point.
It’s similar to the arguments about 3I/Atlas being an alien spacecraft because it’s so ‘weird’.
With so few data points, everything is fundamentally ‘weird’ - or normal - we have no way to tell, so making any sort of statistical argument about it is fundamentally useless and misleading, as statistics is based on groups. And we don’t have a group yet.
We know a lot more than the simple fact that civilization exists on our planet. See section 3 for how they estimated the parameters.
One of the most uncertain parameters is the rate of abiogenesis events per planet. For that one they used a log-normal with a standard deviation of 50 orders of magnitude. They discuss specific theoretical limits from biology for both ends of the range.
Compared to this approach, the usual method is to just pick particular values out of a hat. This paper at least improves that by directly representing our vast uncertainty for some of the values.
It doesn't tell us how many alien civilizations there are. But it does tell us the range of possibilities, given what we know and don't know.
If your level of uncertainty is infinite then you're suggesting that abiogenesis could be happening every day in your back yard. I think you might admit we're a little more certain than that.
Life, once established, is about competition for niche resources. Established life would kick the polypeptides out of a protocell quite easily (with certainty > 99%).
Protocells could be evolving right now at vents in the ocean, with zero of them managing to escape their birthplace due to being outcompeted by things with fully developed organelles.
Fine, let me put it another way. Fill a test tube with simple chemical building blocks of life. Sterilize everything. If our uncertainty is infinite then we aren't willing to say whether metabolizing, reproducing life arises from scratch within five minutes every time we do it.
If you're willing to concede that in fact, that doesn't happen, then you're putting a limit on that parameter, just like the paper did.
It does assume that life must be associatable with a planet. It's a plausible assumption, but you could also hypothetically have life develop on a star itself or its remnants, comets, clouds of interstellar gas. Maybe even something more exotic than that (dark matter? some weird correlated statistical properties of the quantum foam?)
About forty years ago I read a terrific book about life forms that live on a star. Maybe Starquake was it called? Did to the abundance of energy on the surface of a star, they live their lives a million times faster than humans. Thus for both them and the humans who discover them, communication is difficult. I think the humans push these life forms to develop civilization, which from the human's perspective had them go from primitive animals into sophisticated beings of technology past their own in something like a day.
The cheela lived on the surface of a neutron star, and they lived faster because the nuclear physics that powered their metabolism are far faster than the chemical and mechanical physics that power our own.
I'm not against piracy, and I love Anna's Archive... but publicly linking directly to a pirate source for something like this seems wrong. Could've just linked the Wikipedia page and let people acquire however they prefer.
Anyway, sounds interesting, gunna add that to my list
Well I don't really have a line, but that doesn't mean I'm going to go linking directly to such sources in public - not everyone agrees with my stance on copyright. Those who do can easily go find it themselves.
Also Macbeth was written 400 years ago. Let's not pretend this is a fair comparison. This author has been dead only 20 years - it might be that their partner is still alive and needs that money, or their children.
What a strange way to phrase it, considering in your last comment you were talking about how copyright expiry is exactly for this purpose.
Anyway, what is copyright expiration in America these days? 100 years?
Also, is it simply a matter of X years after creation? I somehow doubt it's that simple anymore. I wouldn't be surprised if "copyright is extended indefinitely if the work is being actively commercially used" or some such
Which is saner eh! That way people living at the time who are protecting it (copyright and patents are both protections for things otherwise being distributed and which could be copied easily) can benefit from it eventually.
My initial reaction was the same, then I thought: "no, we need more of this".
We need more discussion about copyright in our society, and we need it most in front of those who are unaware, inattentive, or would otherwise shirk that discussion. Posting a relevant link in a relevant discussion appears as good an avenue as any to get people talking.
Promoting copyright infringement in order to initiate a conversation about copyright is about as moral as murdering civilians to initiate a conversation about human rights.
I was bothered by the nearly a-scientific-ness of PHM. The story was nicely done in general, but it feels like he pretends to be hard science fiction when he's really Star Trek-level.
How many planets are there, and what proportion of them have detectable life?
The f does not have to be structured as fl->fi->fc, although we can see why you'd assume that kind of structure. It's simple to calculate the PI(series) when the model is just a funnel. Like the Million Dollar Money Drop gameshow.
But you could imagine a more complex model of probabilities that branches and merges. There could be events on the bayesian tree that amplify downstream events. For instance, suppose there is some pathway that if reached will leave certain minerals that future civilizations could use. This has happened already on earth at least once: lignin bearing plants could not be easily digested for a long time, and that led to coal formation during the carboniferous period.
You could imagine many such potential trees, but we only have one iteration.
Thanks, I read that part before I shared it. It's pretty clear to me, these are pretty well defined quantities, just hard to measure. What is unclear is perhaps the definition of life. But at no point does it assume a planet must be in the Goldilocks zone. So perhaps you want to point out those assumptions you are talking about to me, because I don't see them.
Edit: the parent post has been edited substantially after I replied.
> these are pretty well defined quantities, just hard to measure.
They are "defined" conceptually, in words, not in physical quantities. It assumes we can assign a known value to any of that when we don't and likely never will. It's like saying "Let X answer the unanswerable question. X is the answer".
> at no point does it assume a planet must be in the Goldilocks zone
You could say it implies it with fl.
> Edit: the parent post has been edited substantially after I replied.
I can't, but the equation itself doesn't to that. The assumptions are up to the reader to make. That's why I think that the equation isn't particularly useful.
That's just your interpretation. Take the equation at its face value and it does allow for life originating around some deep sea vents, like JamesLeonis speculated.
Yes, but we should consider these linkages when setting values. If we assume that volcanic vent life is very unlikely to become spacefaring, we should either leave it out of the "life" term, or leave it in but lower the probability of the "becomes spacefaring" term.
It goes the other way around. The Goldilocks zone is a shorthand attempt at helping us guess how many planets out there are capable of supporting life.
Even if you only had a handful of civilizations, the sheer time that has passed and size of the universe should mean that life should still be alot more apparent.
With sublight velocities achievable today, I recall it would only take around a million years for a Von Newmann probe to cover the entire galaxy. Such a probe is quite conceivable, so why isn't there more evidence of such probes everywhere?
Another point I feel is that proliferation of life should be an self-reinforcing affair, for intelligent life even more so. A spacefaring nation may terraform or just seed planets, and these in time will replicate similar behaviors. At a certain point, a galaxy teeming with life should be very hard to reverse given all the activity. A life itself isn't necessarily evolved from biology, AI machine lifeforms should also well suited to proliferate, yet we don't see them anyways.
> With sublight velocities achievable today, I recall it would only take around a million years for a Von Newmann probe to cover the entire galaxy. Such a probe is quite conceivable, so why isn't there more evidence of such probes everywhere?
What are the incentives to build and deploy such a thing though? We as a civilization fail to fund things that have a ROI of more than a few years, how are you going to fund something that pays off after a million year?
Exactly. Some of the biggest explanatory factors for the Fermi paradox are likely to be economics and politics: interstellar travel is unreasonably expensive, unimaginably slow, and has negative ROI unless your time horizons are beyond anything that's ever been used on Earth.
Consider that in some countries on Earth, we can't even get consensus that obtaining energy directly from the Sun via solar panels is a good idea.
Also, people vastly underestimate how hostile space is: colonizing Mount Everest, the Antarctic or the continental plateau under sea would be far easier than colonizing Mars. And Mars is the most hospitable extraterrestrial place we know of.
I don't think we would colonizing Mars, free floating colonies akin to O'Neil Cylinders orbiting Earth would probably be the more logical option. And with increasing robotic automation capabilities, it's not improbable to see these being built in the future.
"Extremely improbable" would be a better assessment.
Even ignoring the project complexity, difficulty, and energy budget, which can't simply be handwaved away by "robotic automation", one reason is simply that such colonies don't solve any problem that we're likely to have, that can't be solved much more cheaply, safely, and effectively.
But even the idea that we'll eventually have the technology to build such structures is debatable. Will this be before or after we solve climate change, for example? Because that issue is likely to severely impact our technological capabilities over the timescales involved. And as of today, the most technologically advanced nation is doubling down on atmospheric carbon production.
Having the technology to build it isn't the hard part. The question is why you'd do that in the first place and who would fund such a colony.
First of all it's going to be massively more expensive than any housing we've ever built on earth so only a very small elite could afford living there.
But then again, space is a very hostile environment: it's super dangerous (any incident will almost certainly snowball into a dramatic accident), very unhealthy (billionaires are currently funding longevity research, so I don't think they'd like to go in a place where they would age up significantly faster than on earth…), and life is just worse up there on all respect…
At some point replicative drift will set in. How many replications is two million years? How long before the probes evolve? How long before they speciate? How long before a species turns on itself?
> Such a probe is quite conceivable, so why isn't there more evidence of such probes everywhere?
Time, not space, is your answer here.
Two reasons -
(1) civilizations might not survive long enough to do this.
(2) 13 billion years is a long time. So you have the reciprocal of that as the chances to be in the right year to see such a probe. And with results from the new telescope we now have hints that the 13 billion number is bogus, the universe is likely far older.
The fundamental problem with the Drake equation is that it's frequentist, not Bayesian
Hence why you get too high sensitivity to parameters you have no way of having an estimate with a small margin of error
We "don't care" about how many civilisations are out there, we care to the point where we can interact with them.
As mentioned, it has several assumptions. "Rate of birth of sun like stars" means nothing. You can "always" have an exception for life that will throw the data off: "star too bright but with a hot Jupiter tidally locked in front of your moon, shielding it" etc
FYI just about every outer solar system moon or planetoid has a liquid ocean somewhere underneath. Europa is neither exceptional or even that interesting anymore.
I don't see any reason to believe that giant impact is the only way to get life-supporting amounts of water. We know Mars had liquid water. We know Titan has lots of ice. We're pretty sure Venus at least had noticeable amounts of water. Did all of these come from Theia-type impacts? I don't think we have any evidence of that.
Multiple impacts is the standard hypothesis for a source of Earth's water. If I recall correctly, outgassing from volcanos is another source.
Keep in mind, the solar system formed from a relatively homogenous nebula. It was the formation of the sun that forced lighter elements to migrate outwards, and that only happens if the lighter elements aren't already part of a larger object. There isn't much of a difference between a 10 km chunk of ice and a 10 km chunk of iron gravitationally speaking. Bouancy doesn't play a role here, so density doesn't matter. Outgassing does matter, but that is a slow process for large object, like the Earth, or for smaller objects on Earth crossing orbits that don't get too close to the sun.
It's also worth considering that each planet's situation is unique. There is much more water ice on the moons of the outer solar system because there was more water at the time of formation and the lower temperatures mean the water that was there stayed there. As for Mars, even though it is colder than the Earth, it is much less massive. As such, its atmosphere bleeds away lighter molecules (never mind lighter elements).
> Multiple impacts is the standard hypothesis for a source of Earth's water.
Right, which is why it's baffling to me that everyone in this thread seems to be losing their mind over this result, thinking it affects the Drake equation and rewrites solar system dynamics. The multiple impacts thing might not have actually happened to earth, but there's still no reason to believe it wouldn't work.
Yep, mega-impact is a classic example of an ad-hoc hypothesis. For example, Moon formation is much better explained by multi-impact hypothesis, which also requires less assumptions.
Dang, I can't post anything in this thread without someone thinking I agree with them that science is BS. Giant impacts aren't actually surprising in an early solar system that hasn't hit steady state yet. If multiple impacts better explain all the evidence for Theia, including the weird patterns of isotopes and possible fragments deep in the mantle, that's news to me.
I recently became addicted to the SpaceSimsx and SimulaVerse. My takeaway is that so many just slight deviations can extinguish life on earth. I used to think of possibility of life in other worlds just in the lens of statistics. There are so many combinations and possibilities that it seems inevitable. But seeing just how perfectly aligned our solar system is makes me really reduce the probable number of chances of other habitable scenarios in my mind.
These channels helped me realize just how important all the planets in the solar system are to our continued existence. Its as if we have an entire family thats just perfect to make our existence possible. An entire family each one quietly doing their part without fanfare or credit.
No matter what the circumstances, live will evolve to perfectly match the conditions it is under. There are many species so perfectly adapted to their ecological niche, they are in great danger of extinction. Like peacocks, who are stuck in a local optimum with no way out.
Well, just keep in mind that its not a "perfect alignment" as this seems to prescribe some kind of intent. It's more a set of requirements that allowed life to not be extinguished so easily. We could never exist in a place where this didn't happen like this, so obviously we have to be here and not some place ealse. So its more that out of the 1 places we have seen that was made like this, we at least know life happened there.
Could a tardigrade withstand these scenarios? If the answer to any of those is yes, could we then say that even with the parameters skewed a bit, there is a chance life exists elsewhere, and under completely different and extreme or (not "normal") conditions? Is the tardigrade here as a "clue" to tell us that life could form potentially anywhere?
The thing is that even for a super low probability event, the size of the universe is so huge and such events must be happening all the time.
e.g. Say chance of a random planet ever being hit by a water-carrying comet is one in a billion, then with 100B - 1T planets in the milky way it'd happen here 100-1000 times. If chances are only one in a trillion, and we're the one in the milky way, then there are still another 100B - 1T galaxies out there and therefore a similar number of such events.
And you have to have multiple low probability events. These probabilities multiply.
We had a good start. A Jupiter to clear the debris, a Theia impact to create tides and contribute to tectonics, a magnetic core, a shielded atmosphere. We had water delivered to us. Maybe even panspermia.
Maybe cell walls and mitochondria are hard. Maybe multicellular is hard. Maybe life on land is hard. Building lungs, rebuilding eyes, having actual energetic gasses on land...
Maybe life is easy, but intelligence is hard. Maybe civilization is hard.
Maybe technology development can only happen on dry land, because aqueous chemistry is hard in water. Sorry mollusks and cetaceans: you'll probably never be able to do chemistry or materials science.
Maybe you need water and carbon and other chemistries aren't robust enough.
Maybe you need lots of fossil fuel deposits to develop industry. And that requires growth without bacteria and decomposers for millions of years, implying a certain order to evolution.
Maybe you need a certain sized gravity well to escape.
Maybe surviving the great filter is hard and still ahead of us. Maybe every species can build tech where a kid in their garage can extinct the entire species by 3d printing grey goo.
There's just so much we don't know about how life could happen. Let alone intelligent life. We don't even know where we're headed.
My pessimistic side says that the conditions for intelligent life are so implausible that we’re unique, and when we drain the planet dry of easily-accessible fossil fuels we’ve deprived any successor civilization of its opportunity to escape the planet.
Basically I fear we’re the universe’s only shot of appreciating and populating the galaxy (or beyond) and we’re on the brink of throwing that away.
> when we drain the planet dry of easily-accessible fossil fuels we’ve deprived any successor civilization of its opportunity to escape the planet.
There will be no successor civilization to humans. Earth won't be able to support multicellular life in a few hundred million years due to the sun becoming gradually more luminous over time, resulting in higher surface temperatures that will eventually culminate in a runaway greenhouse happening, as it already has on Venus. Due to human-driven climate change effects this event will certainly happen much sooner (<100m years) as well, which is simply not enough time for another intelligent species to evolve after a large-scale extinction event.
Even if life evolving on earth was an incredibly rare event the chance of such circumstances not happening elsewhere even in our own galaxy is infinitely small - there are trillions of planets and 100b+ stars. On top of that there are 100s of billions of galaxies within the observable universe as well.
> Due to human-driven climate change effects this event will certainly happen much sooner (<100m years) as well
No, it will not. Human driven climate change is drastic, but the Earth has seen far worse events than our anthropogenic carbon emissions. For instance, the Chicxulub impactor at the end of the Cretaceous changed atmospheric conditions overnight, and to a much greater degree than whatever we have cooked up. It was the equivalent of detonating the world's entire nuclear arsenal about a million times over.
Sure, it finished off the dinosaurs. But 66 million years later, we, the descendants of tiny rodent-like mammals, are still here, as are the dinosaur's own descendants, the birds.
Additionally, during the Carboniferous about 300 Mya, both carbon dioxide and oxygen levels were considerably higher than they are today, and life actually thrived. I would say that with the increasing luminosity, there will be at least a decent period on Earth where life returns to that sort of diversity. We are actually still only in an interglacial of an ice age—this has effectively sterilised large tracts of our planet by covering them with ice sheets, or locking permafrost into the soil and making them unavailable for large trees.
Let me be very clear: our emissions—if unchecked—will make life very difficult for us as the rising seas and temperatures scatter millions of people out of coastal cities in the tropics further north and south and cause war, division, strife, and discord like we have never yet seen. But actually bring forward the planet's overall demise? Nearly impossible.
Let's not have the hubris to think we puny humans could remotely affect the planet's geological timeline. If we somehow all disappear simultaneously, most direct evidence that we ever lived will disappear with us–perhaps within a hundred thousand to a million years of erosion and weathering. Our emissions will similarly lurch to a halt and will reach equilibrium within a similar time span. That's all it takes to remove our direct creations from the geological record.
> There will be no successor civilization to humans. Earth won't be able to support multicellular life in a few hundred million years due to the sun becoming gradually more luminous over time
Modern humans have only been around for < 1 millions years, and all the technology we have invented is incredibly recent. 200 years ago we had neither electric light or bicycles.
Over the course of 100s of millions of years, as the sun's increasing luminosity becomes an issue, I'd have to assume we could create some sort of atmospheric solar shield to reflect or absorb a lot of the energy. Of course you can only postpone the inevitable (red giant).
Assuming the evolutionary lineage of our species survives a few hundred more million years (which seems rather doubtful), then it's not going to be homo sapiens any more - we'll have evolved into successor species that may be barely recognizable. If you go BACK in time 100M years, our ancestor was some mouse-like animal.
As long as we have air and water (i.e. as long as we're alive), then we can make propellants such as Methane or Liquid Hydrogen and LOX, Hydrazine & Dinitrogen Tetroxide (or Hydrogen Peroxide).
"and when we drain the planet dry of easily-accessible fossil fuels we’ve deprived any successor civilization of its opportunity to escape the planet."
Successor. Whoever comes along after we've done ourselves in.
> ...when we drain the planet dry of easily-accessible fossil fuels we’ve deprived any successor civilization of its opportunity to escape the planet.
On the flip side, that could also be plausibly a blessing, avoiding them to fall into the same trap of becoming too powerful before they get wise. These comics illustrate it: https://www.badspacecomics.com/post/grounded
Even on Earth, the only reason humans exist is because the “local maximum” of the dinosaurs was wiped out by a meteor. Perhaps comparably intelligent dinosaurs would have eventually evolved - but it’s not a given!
Dinosaurs existed for some 200 million years with no detectable signs of technology development[0]. Presumably, the steady state did not produce a scenario in which the intelligence niche would develop without some other less catastrophic global change event.
Intelligence evolved at least three times on earth - dinosaurs (leading to corvids, but a raptors already intelligent), mammals and cephalopods (e.g. octopus).
I suspect that any evolutionary environment will eventually create enough variety and instability that some generalists emerge, creating a reward for intelligence. The rise in intelligence from early water-bound life to later forms was likely all driven by more complex and diverse environments.
Maybe they didn't produce an intelligent species just because they had not the luck of living in the unprecended time in the history of Earth with both high atmospheric O2 and very low atmospheric CO2 we enjoyed for a while, before we started to burn fossil fuels by the gigaton. See https://www.qeios.com/read/IKNUZU
It took several environment-changing events to get our unique kind of intelligence; mammals had to thrive in place of saurs; and then, Africa needed to be split by the Rift and to create the dry savannah.
This forced some apes to climb down the trees and depend on a diet of scavenging for meat, which happened to both increase brain size AND require improved intellect to survive, forcing the evolution of our hypertrophied symbolic brain.
Had this not happened however, other intelligent species could have filled the niche. There's no shortage of other intelligent species in our planet, not just other mammals but octopus and some birds. And then you get hive intelligence, which could equally be forced to evolve into a high problem-solving organism.
You're not wrong, but you're in the wrong place to talk to people about low-probability events and how they multiply. Most Hacker News can't into elementary-school-level probability equations and will instead take the ostrich approach; there was some behavioral scientist dude from Cambridge Analytica who wrote about this and the TL;DR is that most "adults" have infantile minds that prefer various safety blanket mechanisms that society is more than ready to offer them just to do anything to have an excuse to not face the truth of what basic math reveals to more likely than not be true.
There’s not a huge difference between zero and one, other than whether someone’s around to comment about it on HN. And even a second wouldn’t really tell us more about the probabilities.
Just as easily as we can multiply planets times systems times galaxies times cluster groups we can multiply multiple small probabilities of each chemical being present at the right time and right type, temperature ranges, gravity ranges, etc
If the numbers you propose turn out to be accurate then the odds of there being other life are near zero because even 1/1000 planets are not habitable likely.
Huh? Even in the 1-in-a-trillion case, there's still maybe 1 trillion galaxies each with one planet that was struck by a water bearing comet, so even if only 1/1000 of those are otherwise habitable, that still leaves a billion habitable planets in the universe with water.
I doubt water (H2O) is actually that rare. The most common elements by far, both in our own galaxy and the universe as a whole, are Hydrogen and Helium, but the next two most common are Oxygen and Carbon.
At the moment, rapid and massive expansion seems likely with tech only just on the horizon.
Enough AI and robotics for an autonomous factory may be a mirage (such mirages have (metaphorically) happened before), but it seems like it's on the horizon.
Even with relatively mundane growth assumptions, that can go from "species inventing writing" to "Dyson sphere completed, is now sending out seeds to every accessible galaxy" on significantly less than the timescale of light crossing a spiral galaxy's disk.
I think its the fact that if we really wanted to, we could probably make it happen already today. On a scale of a couple hundred million years, its possible we could reach most of our own galaxy, which is a small slice of time in the life span of the Milky Way. So the question remains, why hasn't this already happened, or has it?
Galactic colonization, carried to saturation, would detectably modify the appearance of a galaxy. So called "type 3 civilizations" would convert a significant fraction of starlight to lower grade heat, which would be radiated. Searches have been conducted for this signature, with the result that no more than 1 in 100,000 galaxies has such a civilization, and with the result being consistent with none.
I am not an astrophysicist but I have a hunch any speculations of galactic colonization fails to entertain just how big space actually is. I feel like there is ample reason to suspect the probability of galactic (or even interstellar) colonization is exactly 0, and no civilization in the history of the entire universe will ever colonize an entire galaxy (and probably not even more than a handful of solar systems outside their home world; if any).
Your argument shows a lack of understanding of exponential growth.
Any given colony has to create only slightly more than 1 additional colony in order to drive exponential growth. There doesn't have to be any coordinated action by a central authority for it to happen. For it not to happen (if it is physically feasible), in contrast, every species has to refrain from doing it at all points in their history, almost without exception. And those that do the colonization will seed additional colonies with a mindset that led to colonization; such mindsets will be selected for for further expansion.
Permanent exponential growth is very rare in nature, and even rarer in biological systems. What we observe as exponential growth is usually only a partial observation of a logistical curve or is missing a system collapse at the end of the curve.
We have no reason to believe alien (or even human) civilization will continue to grow and expand forever. Heck even the human population curve has started to slow down and is now revealing it self to be a logistical curve.
But regardless of this, space is very very very big. And there are a lot of extremely hostile worlds out there. Any civilization will experience biological limitation to which worlds they can (and will want to) colonize. Likewise they will experience both economical and physical limitations to how far they will send their machines. Lets say an alien species is lucky and has a habitable world inside their solar system which they will colonize. I think this is likely. They also spot another world in a nearby solar system which takes them 200 years to travel to, eager colonists travel in a generational ship, and 600 years later the colony is thriving. Now they run out of nearby habitable worlds. There is a world of questionable quality 500 years away and they are unable to persuade enough people to fill a generational ship. Also they learned the stories of the passengers in the generational ship, their lives kind of sucked, we have it much better on this world. So it is better to just stay here. This might happen after 1 or 100 successful colonizations, but I think space is so freaking large, it will happen to all civilizations. At some point they will run out of worlds to colonize, and they will never expand far outside of some local area near their home world.
It's rare in biological systems because it's terminated by running out of some resource.
But you're saying galactic colonization would terminate without running out of new systems to colonize.
There would be a slowdown due to geometric constraints -- only so many new systems adjacent the boundary of the colonized zone -- but that hardly solves your problem.
My speculation is that the size of space is an obvious geometric constraint which will limit the span of any civilizations almost immediately.
If we look at humans, we have both the space, technology, and the resources to expand even further on earth, yet our span only marginally larger then it was 10 000 years ago. We can have permanent settlements on Antarctica, floating on the ocean, etc. but we don’t. We can increase our population by another order of magnitude, but again, it looks like we won’t. This follows the same population dynamics as most other species on earth. I think aliens will be no different.
Unless some means of communicating faster than light is found a galactic colonisations is not a civilisation, its multiple ones. A colony ship heading in one direction at 0.1c will never interact with one heading the other way at the same speed. After 10,000 years the civilisations will be very different, after 100,000 years they will barely be the same species.
Even if 99% stop and fail, the 1% will continue and continue expanding.
The only way to stop would be to run out of planets, which would mean every habitable planet and star system has been populated. There wouldn’t be a biological urge to stop, as the successful colonies are ones which have the urge to expand. An environmental need wouldn’t affect every colony and ship short of a galaxy spanning event of some sort which we can’t even conceive.
Yes, I think that will never happen. My prediction is that generational ships are super rare in the universe, and may only happen ones or twice in the entire history of a civilization, and for a tiny portion of civilizations. Meaning by far majority of all civilization will have zero generational ships. Maybe a single civilization somewhere in a distant galaxy will have hundreds, but nowhere near enough to cover an entire galaxy, not even if we count decedent civilizations.
I also think fast space travel (like 0.1c) is rare among civilizations, and may only happen in the order of hundreds of time in the history of some civilizations. And most of these fast space travel will scientific instruments for curiosity and exploration, not for colonization. And that a technologically advanced civilization would favor doing their explorations with telescopes, not probes. So probes would only be sent long distance for rare occasions.
This would mean that almost no civilizations will be expand beyond their solar system, and those that do, will only do it a handful of times, and the expansion will finally stop.
It doesn’t matter how rare it is to get started once it starts. Every ship is a new civilisation that is created, one predisposed culturally and perhaps genetically to spreading out.
Especially once you reach the “hundreds” level then given the technology exists and the people exist why would it stop, until there’s nowhere else to go.
There is the light cage issue where a civilisation can only spread so far with exponential growth before internal pressures overwhelm it (the leading edge never gets a chance to continue as it is overwhelmed by trailing edges)
Even in that situation though you’d still have self replicating probes - likely at a far lower tech level than biological. Once you reach the tech to send one probe which can duplicate itself more than once using resources in a new system then its game over.
Send 50 probes to each of the 50 stars within 15 light years at 0.01c. If 10% make it they then use local materials and send 50 more, that’s 250 out in 1500 years. Then it’s 1250 out in 3000 years. Within a few millennia years you’ve got millions of probes spreading in an unstoppable way. The ones heading back “inwards” will fail, but those heading outwards will reach each new star dozens of times, only one will need to get there. Within 10 million years you’ve reached the entire galaxy.
To stop it you’d have to make a self replicating probe which was faster and did exactly the same thing and caught the earlier probe, but then when would that probe itself stop, it would have no way of knowing if there were any other “bad” probes to find without becoming the bad probe itself.
Living beings are the same. Once a few dozen have made it and passed on, it’s inevitable it will continue. It may leave out a hollowed husk in the origin point with all resources having being consumed in the centre, but that doesn’t matter as the centre has no way of affecting what happens on the edge, and one edge has no way of affecting another edge.
von Neumann probes are a fantasy. I see no reason why any civilization in the entire universe will ever build a successful self replicating probes, let alone ones that are still replicating dozens of millennia later. The reasons include that targeted probes and telescopes can give you pretty much the same amount of knowledge for far cheaper and much quicker then random walking probes across the galaxy. There is also a technical limitation to self replicating probes, even if a civilization will build one, we cannot expect the self-replicating mechanism to last dozens of millennia. Some generations will fail to replicate, and in the vastness of space that may mean the entire lineage will go extinct.
I think you may be expecting an exponential growth when population dynamics almost always favor logistical growth. At some point your machines, or your colonial behavior hits a limit and your growth starts to slow down. I suspect that limit is within the solar system for the vast vast vast majority of civilization. And even if one escapes their own solar system and starts anew on a new home world, they most likely will not colonize another. The space is just so big, and habitable worlds so far away from each other that I find it extremely improbable that any civilization (and their ancestor civilization) will survive more than 5-6 colonization (by far most will see 0).
> Living beings are the same.
They are not. You are describing living beings like viruses (fair enough; viruses are worthy to be considered lifeforms) that spread from host to host until they infect everybody. But viruses don‘t behave like that. The vast majority of them only infect their closest neighbors, and those that do spread towards the limit of all members of the species (like Covid) still fall short and eventually start to slow down their spread in a logistical manner. Growth only looks exponential while you are at the initial stages of spread. This behavior is not only common among viruses, but in fact most population dynamics can be described with logistical growth.
Yes, theorizing a future possibility that has no president is, by definition, fantasy. I mean, you can do fantasy, it makes good science fiction, but until we have evidence that von Neumann probes exist and are capable of colonizing the entire galaxy, it remains fantasy. Theoretically we could build a high speed rail between Seattle and LA, we could build a permanent settlement on Antarctica, and we could replace our jet-planes with hydrogen powered flying wings, but until we do, a world with those things are just fantasy.
The only argument for von Neumann probes that I can think of is as a specific answer to the Fermi paradox. The universe should be filled with these probes, but since it obviously isn’t, we can infer that no civilization has reach the interstellar age.
I reject this framing, the Fermi paradox is only a paradox if you assume that space colonization is a thing that is not just possible, but inevitable. My solution to the Fermi paradox simply rejects this assumption. Civilization will not colonize definitely, they will do their space explorations with telescopes and targeted probes, and they won‘t build any von Neumann probes (at least not ones continue to replicate for dozens millennia).
Aside: I am aware of the irony that my description of civilizations outside of our solar system is also a fantasy.
This is interesting speculation, but it adds one more completely unknown variable to the Drake equation.
What’s the probability that a radio-capable civilization becomes a galactic type 3 one? Looking at the only example we have, it appears very unlikely. It seems much more probable that we’ll destroy ourselves within the next centuries.
I guess it depends what question are we trying to ask. It may well be that there is no other intelligent life close enough to us, or coexisting with us in time, that we will ever be aware of it, but yet the universe may still be teeming with intelligent life.
In either case it's a statistical question of how common is life, and intelligent life, but of course there's the human interest in potential contact with another intelligent life form.
Hydrogen is the most common element in the universe. So long as you have elemental oxygen, it will react with things and hydrogen is the thing it will react with the most. So having water is almost a given for any Star system. Additionally, protoplanet and cometary collisions are in fact statistically inevitable. The real question is if water can be delivered at a point after enough gravity has amassed to ensure the water stays there.
Right, that's the sticky point? The likelihood of a planet in the Goldilocks zone to be too hot in the early stage of stabilizing its chemistry that it requires seeding with "post-formation" chemistry? Is that likelihood close to 100%, or maybe not even near and we were just set up for a funny cosmic event.
I agree. In addition to the chemical elements like water, as mentioned in the article, the impact with Theia also enabled strong magmatic activity at the core of the planet, and that was a critical element as well to sustain life.
Probably the strong magnetic activity of the Earth's core was key to maintaining the atmosphere, but also, the magmatic heat contributed to keeping the planet at a good temperature to support life when a young Sun provided significantly less radiation.
All these elements may suggest that the collision is needed to satisfy the very strict requirements about where the planet is located and about the size and composition of the colliding planet. This makes the probability for life-sustaining planets in the Drake equation extremely low.
As an indirect proof of the tightness of the condition is the fact that the Earth in its history had periods of climate extremes hostile to life, like the Snowball Earth when the planet was completely covered by ice and snow, or at the opposite extreme, the very hot periods when the greenhouse effect was dominating the climate.
Speaking of Drake equations, you should (1) see the other comment here with this account name (2) check out the top Pirate Bay rip of Dark City (which predated that other movie) and turn on the English subtitles and count the number of times the characters look at or make gestures pointing to certain alignments of the text in the subtitles and, if you're true "hackers", try to figure out the encrypted messages in the text alignments that the characters are looking at/pointing to at key moments – and then when/if you figure out what the encrypted messages mean, try to figure out how the director worked together backwards so that they could have a script that aligns a certain way using subtitles and then make the scenes so that the actors are looking/pointing to key spots at just the right time.
If you appreciate technical things, you'd be in for a treat.
Right. It's discouraging. We now know that many stars have planets, and some of them are even in the Goldilocks zone. But if it takes a planetary collision to get water...
And only one planetary collision, because each one wipes out essentially all life.
Look at the rest of the solar system. Mars - almost no water. Luna - almost no water. Venus, maybe water[1], but as steam. Too close to the sun and too hot.
I find it incredibly encouraging. I fear aliens existing in sufficient enough quantity to find us more than I fear Earth being the only host to intelligent life until we escape it.
Probably not the only host, but habitable planets are sparse. If Einstein was right and faster than light travel is impossible, the number of planets we can even talk to is not that large. There are only 94 stellar systems within twenty light years.
Especially in the context of this, I am baffled by people who go to great lengths to prevent life from Earth arriving on other solar system bodies. Such as all the efforts to sterilize the probes.
Historically to prevent pre-contamination and erroneous biosignature readings. This may ease once we have some solid pointers or confidence there may be none (caution is likely warranted due to the gravity of such a discovery).
Consider Mars. Endless probes for 50 years going to Mars looking for life. No clue of life has ever been found. At what point do we face the fact that Mars is a dead rock?
What we should be doing is collecting samples of extremophiles from the Earth, and attaching a few packets of them to every probe going to Mars, and see what happens. Probably nothing will happen, but it's worth a try.
Don’t forget this can only happen once, really. You need it to be such a rare event that it doesn’t keep sanitizing the planet with repeated impacts, but one really perfect strike will bring what you need and allow life to form.
The number of instances where this (something unreasonably unlikely) happened in our cosmological history is kinda surprisingly high. I’m absolutely convinced there’s no advanced life (and CERTAINLY no technological civilizations) outside of earth.
One other example: we gained most of our adaptability, curiosity, and problem solving skills as very tiny mammals while dinos ruled the earth. The only way we ever took over the planet was thanks to an asteroid wiping out all those huge creatures. Suddenly, high adaptability and intelligence and resilience was what mattered, and being big and strong suddenly was a massive disadvantage.
Our intelligence exploded largely because that extinction event removed almost all major predators, turning earth into a giant survival puzzle sandbox for mammals to grow in.
Edit: our brains only grew big because it was the best means of survival - they’re crazy expensive, so without this “sandbox puzzle” effect, we probably never would’ve grown them.
> Suddenly, high adaptability and intelligence and resilience was what mattered, and being big and strong suddenly was a massive disadvantage.
Maybe it was just being small, puny, and having a tendency to cower in burrows was what saved us. Our ancestors may not have been much smarter than squirrels, and squirrels aren’t very bright.
Hominids brains didn’t get big until long, long after the KT extinction. A Tigers brain is not that much smaller than that of an an Australopithecus.
Correct - that’s what SAVED us. What allowed us to thrive and dominate the planet was what I mentioned.
It may be more correct to say that growing a larger brain (larger than a lizard’s, I mean) was only realistically possible because of the sudden loss of predators.
Earth has been struck by large comets many times killing the majority of life on the planet each time. In an early solar system it would be more frequent. Once a comet impacts there is one less comet out there. The solar system cleans up over time making impacts less likely over time.
"The hypothesis that life, in the form of “seeds” or spores, is distributed throughout the universe, traveling between planets, moons, and other bodies via space dust, asteroids, comets, and possibly even spacecraft."
I want to think that the water contained life and not the barren earth.
Bit of a nit but the Drake equation is intended 'to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy' (from the Wikipedia entry for it). Nice thing is that you can drop a few terms to get to origin of life.
Mars is technically in the goldilocks zone of the solar system... but water on Mars boils at 0C or 32F due to low atmospheric pressure, which really sucks.
There is a hard limit on the number of atomic elements, and an even smaller limit on the number of soluble compounds that facilitate chemical reactions, and water is demonstrably both the best and the most common in the universe.
So while it may be possible for life to exist without water, any alternatives should be reasonably expected to be even more rare than water-based life
There's a reason life is carbon-based, and it's not random. It's the only element that works, due to abundance; ability to form many bonds; bonds that are just durable enough but not too durable. There's plenty of sci-fi about silicon-based life, but that's infeasible fantasy. And no other elements have any hope. If you have carbon-based life, you need water as solvent and medium.
It's a pretty safe assumption that all life requires water.
> due to abundance; ability to form many bonds; bonds that are just durable enough but not too durable
Well, the thing is that all of those are environment-dependent.
We do have data on a somewhat diverse set of environments, and it's enough to confirm what we knew about the flexibility of carbon. But it's not enough to disprove the alternatives.
1. xbmcuser’s point:
They challenge the anthropocentric (Earth-centric) assumption — “we only know life as we know it.” Philosophically valid, but scientifically weak without proposing a viable alternative chemistry.
2. joshuahedlund’s reply:
Grounds the argument in chemistry and probability.
There are only ~90 stable elements → a finite combinatorial chemistry space.
Among possible solvents, water is the most abundant and chemically versatile (dipolar, wide liquid range, high heat capacity, good at dissolving ions and organics).
→ So even if other solvents can work (like ammonia, methane, formamide), the odds heavily favor water-based life.
3. caymanjim’s addition:
Brings in carbon’s unique valence behavior:
4 valence electrons → can form stable, complex chains and rings.
Bonds are strong but not too strong → dynamic yet stable biochemistry.
Silicon (next best candidate) forms brittle, static lattices and poorly soluble oxides → bad for metabolism.
→ Therefore: if life is carbon-based, water is the only sensible solvent.
But when you dig down deep on theories like that it just doesn’t make sense from a chemistry or physics standpoint. Everyone saw that Star Trek episode about silicon based life and ran with it as being possible. It’s just a show.
A brilliant summary! You've deepened the question from "Does a habitable planet exist?" to "Does a planet successfully complete the complex dynamics of life's origin?" The habitable zone is merely the ticket, while the conditions you mention are the truly demanding filters. Considering this, the probability of our existence truly seems miraculous
Ig Nobel has been around a while. I wonder if there is an opportunity for them to add a feature whereby they (and donors) could _sponsor_ research in areas that would be considered candidates. Research that would otherwise be too trivial or arcane to be funded.
Was thinking the same. Not only would shifting industry to ECMAScript or something else get around trademark nonsense, but now that I think about it I do hear non-techy manager types get confused to this day and call it Java. Also seems like time is right as less is done in plain JavaScript- it’s Typescript, React, framework du jour, WASM.
I guess the hard part is convincing an industry to use a different word.
I did same at first but then recognized it as something that has affected family members. Would be nice to find a name that is a little more respectful to the victims. I can tell you victims already have guilt/shame for falling for these things. I would send them the article but don’t want to call them “pigs” on top of what they have already suffered
I have a family member falling for these on a regular basis. In their case it’s possibly tied to mental health issues. They are able to drive, converse, care for self, but are sending money to groups that are clearly not real (example: fundraiser for a celebrity supposedly in the hospital, when news shows they weren’t. Was convinced actually conversing with the celebrity). Rest of the family has taken some steps but does feel at a loss. How do you prevent them from being seriously hurt emotionally and financially while respecting their autonomy and dignity? Even when they “come anround” to the fact they have been scammed, that adds insult to injury. The vector is definitely social media and sms/phone.
Any tips would be appreciated. Locking down phone hasn’t really helped, and finances are already segregated to hopefully avoid giving away total life savings.
Sounds like some form of guardianship/conservatorship is in order. Talk to a lawyer, if you haven't already (maybe that's what you mean by finances are already segregated).
Build those things into your estate. My family made a trust that pays bills and what not. So your income goes to the trust and you use it to pay regular bills and groceries and what not. Anything on the "not-approved" list takes a vote of the people controlling the trust (parents and kids). That has helped us avoid some bullshit so far.
Of course, you avoid the pig butchering, but open yourself to abuse from the trustees. Reasonably want a new BMW? Hope your kid is ok with their inheritance shrinking by $60k. Etc.
I'm not claiming a trust is a bad idea, only that you need to take care picking the trustees. And be sure there's an "out" if you and the trustees fall out.
Right- “where are all the aliens?” is answered by either “they don’t exist” or “they do but physics of the universe prevent them from moving between solar systems.”
Or: we're the first (or among the first). The history that led to space travel (modern human technology) has passed through an insane amount of unlikely scenarios.
A few of these:
* Astronomical: the sun is unusually calm for a star. Jupiter blocks comets. Saturn blocked Jupiter from destroying the Earth.
* Earth is 4.5 billion years old. In the next 0.5-1 billion years Earth will become unhabitable because the sun's luminosity is increasing. We're in the twilight years of the (life-supporting) planet.
* Above point + think about all the species that came before us. Life appeared 3.5-3.8 billion years ago. It took that long to get to humans.
* Dinosaurs got wiped out. Would humans have even evolved if a cosmic event hadn't cleared the board?
* We think that human ancestors dropped down to about 1000-100,000 individuals about 900k years ago.
There's also the question of how many sun-like stars in terms of metallicity there are that preceded the sun. Our sun inherited a lot of heavier elements from a previous generation of star(s).
Add all of these together and we might be early to the party.
I can’t vouch for its scientific plausibility, but one of my favorite bullets to add to this list comes from Frank Robinson’s novel-length scifi exploration of the plausibility of extraterrestrial life:
“The next step is crucial. The simple organic molecules have to be shielded from the ultraviolet radiation of the primary. That requires a large body of water—an ocean—to protect them. No protection and the molecules break up as soon as they're formed. And oceans of water are … extremely rare.”
…
“But something else is rarer still. The next step in the creation of life is when the amino acids form into long chains.
Left in the ocean, they drift apart as easily as they join together. There has to be a means of concentrating them. Once a certain level of concentration is reached, they'll form long chains, more complex molecules, automatically. Heating isolated bodies of water would help, say tidal pools warmed by hot lava and occasionally replenished by the sea.”
…
“Do you understand, Sparrow? Tidal pools implies tides and that means a moon large enough to raise them—though not too frequently, because you might dilute the pool too much. A combination of the primary and the moon would raise larger tides less often, and that would be a happy medium. What's required, then, is a planet that has land surfaces, oceans, and a large enough satellite to raise suitable tides. The action would concentrate the simple amino acids and they could combine into the longer chains.”
The novel is The Dark Beyond the Stars, and I recommend it highly.
I first read that same argument when I was twelve or so way back in the day in The Tragedy of the Moon (1973), a collection of nonfiction science essays by Isaac Asimov.
I believe this argument is fallacious. There could be infinite other ways a species could have evolved to acquire space technology. A smart dinosaur that evolved to use arms and tail could perhaps have built an industrial civilization. They would’ve been now 100 million years old! Imagine the progress. Them being wiped out probably just delayed civilization by millions of years.
Well, dinosaurs learned to fly instead. And perhaps they ended in a local maximum that made them survive and thrive but did not allow development of larger brains.
Not that humans with their troublesome egos are necessarily anywhere near global maximum.
Yes, but they didn't. I do concede that it's possible that they could've.
But even that doesn't guarantee anything. Modern humans are ~100k years old. It took us nearly all of that time before we discovered agriculture. And it still took thousands of years after that to end up with industrialization. Before then our societies barely improved. It's entirely possible that if society had gone differently that we could've delayed or avoided industrialization altogether. The same could've happened with dinosaur-people.
Or by "none exist right now nearby". If there are technological aliens 3 bly away and 3 bya, we won't likely discover their signals. If there are technological aliens 10 ly and 10 ya then we're extremely likely to pick up their signals (if they emit any), but they're not likely to come here -- not anymore than we are to go there. The Fermi paradox is most easily understood as "the probability of two concurrent technological species in different but nearby star systems is vanishingly small".
For all we know there have been thousands of technological species in our galaxy, but never two at roughly the same time and roughly close together, and never will be.
This feels very defeatist to me. Technology continues to advance, exponentially. And there are hypothetical ultra fast space travel technologies that we haven’t yet been able to fabricate but could theoretically in the future. e.g. Alcubierre warp drive.
Why should we believe it will continue to advance exponentially? And even if it does, we many find none of the hypotheticals pans out - perhaps we advance exponentially and there is nothing feasible to reach even 0.01c
Yeah it's always quite naïve to say technology will be always exponential. We only had like a few thousand years - if it's logarithmic we wouldn't know it for the next 10000 years.
If the Alcubierre drive were possible, some civilization would have already discovered it, and we would see evidence of its use. This is certain to be the case with any kind of FTL travel, if such a thing is even possible.
But when we observe the universe we see nothing. Therefore either no advanced life exists in the universe besides ourselves, which seems unlikely, or none have spread to space in any significant degree and FTL is either impossible or so difficult no one bothers. There doesn't seem to be a secret third thing that both satisfies our observations and obeys known physics.
Something like Alcubierre drive must move fast (0.1% of c at least), be very heavy and dense (to create protected environment inside), and emit lot of high energy gamma rays because a spacetime with negative energy will accelerate light a lot.
More like technology evolves in spurts. Huge gains within a specific area for 2-3 decades and then only small incremental advancements for the next 2-3 decades.
>More like technology evolves in spurts. Huge gains within a specific area for 2-3 decades and then only small incremental advancements for the next 2-3 decades.
I'd expect that the time scales between spurts, while getting shorter over the past 350 years or so, were generally much, much longer.
We first started using stone tools more than 2.5 million years ago. We didn't start effectively using fire for another 500-750k years.
It was another 1.75 million years before we began harvesting seasonal "crops" we identified in our nomadic travels, and another tens of thousands of years before we founded permanent agricultural settlements.
Doing so (and the food surpluses enabled by such) allowed for specialization and R&D into stuff that wasn't directly related to food production.
That really kicked off a technological spurt, which included writing -- a technology that was, perhaps, the biggest step forward, until Liebniz/Newton's Calculus.
Given the immaturity of our current understanding of physics (Standard Model/General Relativity), biology (DNA research) and the like, it seems we're likely to continue without another spurt for quite some time.
I, of course, could be wrong. But since history is often a good guide to the future, I don't think so.
The fabric of spacetime itself sets the ultimate speed limit. Nothing can locally move through it faster than light. For example, gravitational waves ripple across the universe at light speed.
Anything that exists within spacetime is bound by this rule. The only odd exception people point to is quantum entanglement, but while the correlations appear instantaneous, they can’t be used to send information faster than light. Sending matter is distant second.
So, if we ever hope to travel faster than light, we wouldn’t do it by "outrunning" gravity. Instead, we’d need to find a way to manipulate spacetime itself, like bending, warping, or reshaping it ... since that, in the first place itself, is what is defining the limits of motion.
I believe "c" is the upper limit of allowed speed in this spacetime itself. Light just so happens to be the fastest of all entities in this spacetime. Thus, we see "c" as the speed of light. and not the max. speed limit imposed by the spacetime.
I think our recent forays to microscopic and sub-microscopic things like computers have really distorted our views. Just look at something like EV. Give say 10x efficiency(very high) increase and we are actually still faraway from even interplanetary travel.
Physical world is big and getting from one point to other takes lot of energy and involves lot of mass.
Especially if we are actually on the cusp of ASI from self-improving AGI systems. That seems like the most likely scenario where technology emerges that we cannot currently fathom.
I dislike either/or answers in such open-ended scenarios. It points to our lack of humility in the vast unknown.
eg: maybe they exist(ed) but once a civilization gets advanced enough to build FTL-like travel, they invent AI and use it for warfare and then soon cease to exist. This would mean there are potentially many civilizations (and AI?) that are budding and could travel through the universe.
eg: We aren't in an interesting enough place to bother visiting.
eg: they exist and know about us but have "prime directive" (Ala: Star Trek) laws that state they can't make contact until we reach a stable enough civilization to invent warp drive (or some other advancement.)
eg: There is some exotic reason that our pocket of the Milky Way is un-navigable.
We know enough physics to rule out any ftl travel. Assuming that is correct which seems very likely they can't get here, even radio signals is question able - even if radio signals can get here either they have already passed and their civialization (sun) is dead or ours will be dead by the time they arrive.
Cherenkov radiation is a proof, that FTL is possible. We just cannot accelerate enough. However, «burps» from blackholes are proof that blackholes can do that. To achieve singularity, outer layer of blackhole core must spin at a FTL speed anyway.
Cherenkov radiation shows that FTL is possible in a medium where light is slowed down below a the maximum possible speed allowed by special relativity. It does not show that FTL as usually understood is possible.
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