To be fair, quacks that claim to be able to do magical stuff are still around, some do quite well well for themselves even

My suspicion is that it’s abiogenesis, but it’s only a suspicion that I can’t have any certainty of

Doesn’t it demonstrate that the actual dinos in real life don’t have to be big to be popular, because humans will simply portray them how they want to see and bring interest in the species regardless?

I mean, raptors

Similar story where I work, manufacturing a type of x ray emitting tool. Never seen anyone having problematic readings on the dosimeter badges, but when I was hired I did get told that they had only once had an incident, where one of the engineers had been for some reason repeatedly testing a prototype by directly holding the sample the x ray was firing at in his hand. Not sure what happened to him

If you’re actually curious, or someone else reading this is, you never can get a rocket, or anything with mass, to the speed of light either, not just faster than it, but you can get arbitrarily close. However, you never notice anything stopping you going faster than your current speed, there’s no point where your rockets stop working or anything, rather, time and space stretch and squeeze such that neither you nor anybody else see you going faster than light. If you have a magic rocket that somehow has infinite fuel and can fire forever, you can actually get anywhere as fast as you want, from your perspective.

Alpha centauri is famously about 4 light years away, but you can get there in 2 seconds, from your perspective, if you go fast enough. But, everyone on earth will see slightly over that roughly 4 years go by in the time that for you is just 2 seconds. (You’ll see them move slowly too at first, since they’re moving relative to you just as fast as your ship is moving to them, but when you slow down, you’ll see them seem to speed up until you’ll have seen them do 4 years worth of stuff by the time you stop). Meanwhile on your ship, you don’t see yourself crossing that 4 light year distance in less than the allowed time either, because space itself is squished kinda, so that the distance to alpha centauri is shortened to the point that if you’re getting there in 2 seconds, it’s now less than 2 light seconds away, from your perspective, and you’re not moving faster than light to cross that distance in that time. People outside will also see your ship compressed like this too.

This isn’t just a regular optical illusion either, space and time really are different for the people on and off the ship (and indeed very slightly different for everyone anywhere). Nobody has the “correct” view of the universe, because everyone’s perspective is equally valid.

I imagine any explanation of the expansion of the universe for people that are not themselves studying astronomy is going to be simplified in a way that gives the average person the basic idea but not the complete picture to avoid confusion when explaining the concept. Ive not studied astronomy, but I did get most of the way through a physics degree, and know that at least there, a lot ideas are explained in that sort of way to people without much knowledge of the subject, especially the more confusing concepts. I wouldnt be surprised if thats the case for most fields of science. For a different example as an analogy, its common knowledge that you cant move faster than light (ignoring the whole expanding spacetime stuff), but it isnt always explained why this is the case, leading to questions from some people like “what happens if I fly a spaceship to the speed of light, and then turn on the rockets to try to go faster?” which have easy answers or just dont make sense as a question if one has had the behavior of objects at high speed explained, but which seem reasonable enough questions to ask if all youve been told is that the speed of light is just some cosmic speed limit. People cant reasonably blame you for finding an incomplete explanation you’ve been given, well, incomplete, and then asking questions that come to mind as a result.

Dont we see other galaxy groups though? Im no astronomer, but I do recall the universe having some degree of structure above the scale of individual galaxies, with groups and clusters of them forming larger groups or filaments surrounding voids of space with fewer galaxies in them.

Edit: quick search in wikipedia brings up a list of a few groups and clusters known, of which the local group is merely one: https://en.wikipedia.org/wiki/List_of_galaxy_groups_and_clusters

I’m guessing you misread the title as animals instead of mammals, and then didn’t read the actual post text

I’d argue that our civilization is more capable of solving it’s own problems than it ever has been, just because we are are far better at identifying them, communicating them to the rest of the world, and analyzing the effects of what we try. Just because we have not solved all our problems does not mean that people in years past would have been able to do so and we’ve somehow lost that ability.

I used to be pretty excited about 3d printed homes, but an argument I’ve seen, that’s made me a lot more skeptical of them, is that much of the work of building isn’t putting up the actual walls, it’s all the wiring, plumbing, installing windows and climate control and insulation and roofing and whatever else like that that turns a building from essentially an artificial cave into a more livable space. A 3d printer that prints you walls out of concrete or whatever is only doing the easy part for you in that case, and not necessarily even in the most efficient or desirable manner. Not to say that the idea of more efficient ways to build housing cheaply isn’t interesting to me, I just think that it’d be something more boring, like a a bunch of improvement to modular prefab construction. 3d printing is an awesome technology, but it’s not a good option for everything

Probably, if they hang around us and study us that often

Humans, unlike the animals that human keep as pets, are capable of complex speech, so I’d bet that treats would be marketed towards the humans themselves, so that the humans then push their keeper to buy those treats. Sorta like how lots of ads for toys are marketed towards kids, because advertising works better on them and then they’ll go and push their parents to buy them.

The aliens would have to be stupid to list a planet as solved for tens of millions of years after killing off the dominant life forms, because, well, a new one will just evolve in short order, exactly as has happened on earth, and they ought to know this.

The asteroid that wiped out the dinosaurs would be insufficient to eliminate a life bearing planet as a potential future source of a threat appearing, unless you hit such planets regularly in that manner every few million years or so. If you were really going to do a policy like this, you’d want to hit the planet hard enough to completely sterilize the place, or at least kill off everything bigger than a microbe.

Not at all, there is nothing physically impossible about someone engaging on projects that take centuries or millennia to complete, it just requires a lot of patience and effort. Finding or even attacking an alien species does not fundamentally require anything disallowed by physics, it just requires a long timescale to do slower than light. My assumption was just that any hostile aliens would simply conduct those hostilities over very long periods of time. Having interstellar travel at all, assuming no ftl, sort of implies a willingness to undergo these kinds of long term efforts anyway, and it doesn’t seem absurd to imagine that anyone with the technology to have those kinds of energies at their disposal might also have very advanced medical technology, such that they might live a very long time, which could lend itself to more long term thinking.

I’m aware the information would be out of date, that was part of my point in another response for one of the reasons I don’t imagine the scenario works, because attacks arrive at a distant point in the future. I’ve never personally heard the dark forest scenario as requiring ftl tech, making that a requirement seems to make the entire premise moot as it requires throwing a pretty fundamental part of physics out to even contemplate.

I was presuming that nobody has any ftl tech, given that it seems to violate the laws of physics for such a technology to exist. And you can look virtually everywhere, in the galaxy at least, with the right technology (and probably less advanced a tech than needed for manned space travel, what you need is a machine, capable of using the resources available in some asteroid to construct more of itself, and send those copies off towards other star systems. These probes would multiply exponentially until they’ve explored every star in the galaxy, with no further input required beyond building the first one)

The resources required to attack every life bearing planet only really becomes super expensive compared to waiting for civilization to arise if life is very common but civilization is not, which is admittedly a possible scenario, but by no means guaranteed. But consider: any civilization capable of launching an attack on another, particularly one that can be considered highly likely to completely destroy the target in a single strike (which you absolutely need, because if a target survives your attack, it now knows that you exist and even if it did not also follow your “attack everyone” doctrine, will see you as an existential and hostile threat) must necessarily have interstellar travel technology. The amount of time needed to develop this, and the amount of energy and resources this capability implies, make it highly likely that they have very good automated manufacturing as well. With those two technologies, you dont need to listen for radio signals or similar. You can send a tiny and difficult to spot or trace probe to every star out there (potentially at almost no cost if you can make a probe that can extract raw materials and build copies of itself, but even if you cant do that, the probes can be much smaller and lighter than a planet killing projectile and so if you can build one of those, you can at least launch a probe to every world with atmospheric compositions indicative of possible life, to observe from close range and tell you if civilization arises there. Thus, any civilization that wants to follow this policy is impossible to hide from, it doesnt matter if you send radio signals or not, or if you build structures that are visible or not, because your position was compromised before you even considered that there might be something to hide from. If youre a civilization that worries that aliens might be hostile, then, trying to hide makes no sense, because it wont help. What would make sense instead then is to try to grow as far and as fast as possible, in the hopes of acquiring enough redundancy that your neighbors dont have the capacity to destroy you, or at least enough that they arent sure that they do. This kind of growth doesnt seem to be the policy of anyone we see either though, because it should be visible even to us (we can see stars, and if you want to grow as much as you can and have automated manufacturing, you could start to build dyson swarms and similar structures that would visibly change the amount of light that reaches us from a given star).

Now, there are a few responses to this line of thinking that I’ve seen: The first is that a civilization this paranoid might not want to expand to other stars, because a colony in another system is so distant as to be effectively a new civilization, which might turn hostile to you, and is right at the next star over, and so civilizations might just stay in one star system and launch attacks from there. This doesnt really help them hide, as for the reasons Ive just mentioned, they should be easy to spot by anyone that actually has the ability to threaten them, but it might make it less likely for us to see, which is all that matters for the fermi paradox. But these aliens would still be able to send out probes to spy on our planet, so if theyre within around 5000 light years or so, they should have been able to see us develop civilization, and so if thats what they want to destroy, we again, shouldnt exist to contemplate this right now (and if theyre much further away then this, and theyre still worried that we might be a threat, then they really do need to destroy us before civilization ever arises, for reasons Ill get into in a moment). These hypothetical aliens must in order to make sense have a different policy than just “destroy anything smart enough to develop civilization”. The next most obvious trigger then is “destroy anyone that makes it into space”. Suppose then that you’re these aliens. Your probes report some aliens on a planet 500 light years away (given the galaxy is in the ballpark of 100000 light years wide, this is in your cosmic backyard, relatively speaking), or if youve not done the probes, you hear some radio signal indicating this. You decide to launch an attack. But, you have a problem. That signal from your probes (or the radio signals if you hear those instead) was sent out 500 years ago, and even if your attack moves at lightspeed (it wont unless its something like a laser, but you probably want to launch something at a large fraction of that speed, so lightspeed is still a decent estimate) its still going to be 1000 years between when that species started going into space, and your attack arriving. Thats almost certainly enough time to colonize a lot of their solar system, so just attacking their homeworld probably isnt enough. Do you attack every large celestial body in that star system just in case? They could also have significant habitats and industry and such in orbit of various objects, or in orbit of their sun, so even that might not be enough. Worse, that thousand years of space could be enough time to start to get into interstellar travel themselves, so you might need to target every system within a certain radius of their home star, and even worse than that, if theyre just as paranoid as you, its enough time that they could conceivably begin to launch their own interstellar attacks, and if they happen to see your home star and think “that looks like it might have life, lets attack it”, then your policy was insufficient. Youre not launching an attack against a newly space fairing civilization, youre launching one against whatever exists in that area of space when your attack finally arrives. Thus, you really need to attack well before civilizations start to go into space. If we’re anything to go by, the time between early space exploration and industrial revolution is only a matter of a couple of centuries, so something like industry or radio is also too late, unless your targets are in a very narrow window of distance. If you’re within a few thousand light years (still relatively close compared to the size of the galaxy) then you really should be attacking by no later than the first sign of early civilization, and if youre farther than that, as I mentioned earlier, you really should attack before civilized life ever even arises, because there would be time for a planet to go from having literal cavemen to an emerging interstellar empire before your attack even got to them, and once they have interstellar travel, you dont know exactly where they’re all going to be, and they have the capacity to at least try to attack you. So, you either attack before civilization in which case we shouldnt be here, or you colonize the galaxy yourself to have outposts nearby to any emerging aliens, which is fundamentally not stealthy, and which again means we shouldnt be here because our planet should have been colonized by said aliens before we could ever evolve.

The other response Ive seen before is that maybe, nobody is actually willing to engage in a policy of genocide at first sight like this, but everyone is afraid that someone might be doing so, and so everyone hides despite there being nothing to hide from, and so we see no aliens. But this assumes that everyone considers this possibility, deliberately holds back their own development by trying to hide, despite probably also realizing that hiding is futile anyway, and that nobody across the galaxy ever, or has ever, not done this and so had the galaxy to claim for itself, which seems absurdly unlikely, especially given those hiding still have the option to send the probes, and potentially discover that everyone else is doing the same and so knows of them anyway.

The TLDR of this, because I know this was a rather lot of text for just a response to this, is: The dark forest assumes that one isnt a target unless one takes action that reveals oneself, and that one can be sure of destroying any civilization one knows about in a first strike, and that these are the only options available with no way to try to make oneself a less vulnerable target. None of these assumptions seem reasonable upon further pondering, and if they do not hold, the scenario does not make sense.

Fortunately for us, this one isn’t too likely, because realistically, an alien civilization capable of travelling the relevant distance and destroying another civilization isn’t something that can be hidden from. They should be able, fairly easily, to examine every planet in the galaxy and see which ones have life on them, and wipe it out before any civilization ever arises at all. The fact that we exist at all necessarily implies that nobody in this galaxy has been committed to going this, at least for the past billion years or so.