True, but first of all this only works in the context of there already been relatively few ETIs. If the number of ETIs that have existed through the galaxy’s current lifespan is in the millions, then even the short window of noisiness for each one still implies a constant level of noise.
Secondly a lot of detectable signs of cilivizations are not actually pulse-based. Replicating probes, megastructures, large scale chemistry etc.
Here, take a look at this:Galactic Map of Every Human Radio Broadcast - How Far Have Our Signals Traveled Into Space?
That is radio signals, travelling at the speed of light for coming up on 100 years. The idea that we will be littering the universe with physical bric-a-brac soon is ludicrous. Aside from the fact that there is no reason to do so, the notion that we can or would is based on a misunderstanding of just how monstrously vast this galaxy is.
Dismissive language doesn’t negate the fact that on a generation craft with humans, there will be millions of moving parts that will wear with friction. You can’t engineer that away.
Again, you are taking a hypothetical civilization. We have zero evidence they exist. You can’t argue from a point of something you’ve basically made up.
Also, you didn’t answer my question, if you belive such a civilization with that technology exists, why do you think we aren’t seeing them?
As I posted earlier, until we know what the chance of life spontaneously arising, there is no way to intelligently guess. The vast number goldilocks planets is only half of the equation. Here is an equally compelling video against:
For the record, though, I lean towards there being a few other civilizations out there.
I love that guys videos. As far as what would alien life be like, I’m guessing evolution (in some form) would have to be a thing for life forms to, well, evolve.
I haven’t been following this thread in a while and am just catching up, so, with apologies, I’m responding to some very old posts!
At a rough estimate, the Milky Way contains around 200 billion stars, and we believe, based on local observations, that most of them have planets. If only one in a thousand of them had a planet where carbon-based life as we know it could evolve, that’s still 200 million habitable planets – and it’s probably much more than that. The idea that Earth is the only such planet where life actually did evolve is so incredibly unlikely as to not be worth considering.
Except we absolutely do not have evidence that there’s no one out there. We lack such evidence, in circumstances where the incredible vastness of space makes detection of intelligent alien life exceedingly difficult and improbable, so lacking such evidence should not be surprising.
It’s worse than that. What would we expect to see after 50,000 years at that distance? The incidental radio waves, or even powerful directed ones, from any technological civilization we could imagine would be undetectable at that distance with any known technology, and perhaps undetectable even in theory due to the rapidly diminishing signal-to-noise ratio of space itself over vast distances. The arrival of a single photon won’t be distinguishable from anything else.
Once again: we’ve already started. And an awful lot of craft can be made if they are self-replicating.
Of course, as you alluded upthread, you’re incredulous that creating self-replicating probes is feasible. That’s fine.
Personally I find that an unconvincing blocker. Humans went from never having left our atmosphere to landing a probe on an asteroid within 1 human lifetime. I don’t find it plausible that the remaining computing, mining, shielding etc problems will inhibit all species over deep time.
Also please don’t condescend about not knowing how vast the galaxy is. Not only have I discussed interstellar distances many times on the dope, but I’m making an accurate model of a galaxy as a side project.
Of course you can. Firstly, once again we have no reason to assume only the use of manned vehicles. But secondly no, I see no essential laws of physics that dictate that a vessel must have moving parts that can wear out.
Once again: of course it’s hypothetical. The whole topic is speculative. We’re just throwing out hypotheses and discussing reasons to favor or disfavor particular ones. And, given the deep time available, an advanced ETI is likely to be millions of years more advanced than we are.
Or, if we want to speculate that no species reaches that level of development then that’s the primary hurdle – whatever thing stops all species.
I think most likely there are few to none ETIs in our galaxy. It’s an extremely depressing conclusion to come to. But looks the best bet currently. Hopefully further information will change this picture.
I think the idea of supposing how far we could go in hundreds of thousands of years (if not millions), since we are the only example we currently have, is not exactly the way to go. The faster we progress the less likely it is we will survive to solve the many problems we will need to overcome to travel the stars, and while we have only one example that points to self-destruction (us), we have absolutely none that points in any other direction.
Not sure if you are talking about the Great Filter theory or something else.
Nevertheless, for purposes of this thread, even if a Great Filter kicks in life still evolved. Evolved and killed itself but more than one planet has life (probably). And, presumably (given the timescales involved) probably all over the spectrum of evolution from microbes to space-faring societies.
“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” - Arthur C. Clarke
ETA: Has anyone ever postulated that we are the first sentient life in the universe and the first to go into space? Seems unlikely but maybe?
What is the chance that life arises out of inorganic materials? We don’t know - full stop. 200 million (potentially) habitable planets is a very big number. But if the odds of life arising is, say, one in a trillion the odds of life out there is almost nil.
A pithy quote to be sure, but I’ve never bought into it. In fact, neither are terrifying. If we are alone, that’s sad, maybe, but it is what it is. How can it be terrifying when we are all going to die anyway?
And if there is other life out there, that’s a cause for celebration. I don’t assume we will be alien food. Nor do a lot of folks that are running SETI.
Reading this thread, and hearing “Deteriorata” in the back of my mind.
Go placidly amid the noise and waste…
Actually:
The Miller–Urey experiment,[1] or Miller experiment,[2] was an experiment in chemical synthesis carried out in 1952 that simulated the conditions thought at the time to be present in the atmosphere of the early, prebiotic Earth. It is seen as one of the first successful experiments demonstrating the synthesis of organic compounds from inorganic constituents in an origin of life scenario. The experiment used methane (CH4), ammonia (NH3), hydrogen (H2), in ratio 2:2:1[3], and water (H2O). Applying an electric arc (simulating lightning) resulted in the production of amino acids.
Also see:
“You are a fluke of the universe…You have no right to be here”
Organic compounds are not life. The experiment was a proof of concept for abiogenesis (the origin of life from non-living matter), not a creation of life itself. Creating life is a complex process that would require many more steps to form a living organism. None of that can point to the actual odds of spontaneous life.
But they did make organic material from inorganic material. Sure, they did not poof-out a human from a lab beaker but it is certainly the first step and there is no reason to think it only ever happened on Earth.
Life as we know it probably cannot arise out of inorganic materials, but organic materials can and do form spontaneously out of inorganic ones, and they’re found not just on Earth but on Mars and other planets and have even been detected on exoplanets. Organic compounds are basically compounds with carbon-hydrogen or carbon-carbon bonds which can form long complex chains and are the basis of biomolecules and ultimately the basis of life.
So given the apparent prevalence of organic compounds beyond Earth and beyond the solar system, what would have caused life to evolve only here and nowhere else with suitable conditions? It was either some extraordinarily special condition that exists nowhere else, or some astronomically unlikely happenstance that has occurred nowhere else in the galaxy. It seems much more plausible to believe that neither of those fantastic improbabilities are true.
Nor did they poof out a single cell organism. Many scientist have been trying since then to take it to the next step - without success. That tells me it’s not an easy process. Also, IIRC, the gasses they used were incorrect for early earth.
I don’t necessarily think it only happened on earth. I was addressing the point that just because there are 200 million potential planets that there must be other civilizations out there. Without know the actual odds of life arising, the 200 million figure is meaningless.
We may not ever be able to know that but we do know it happened at least once.
When doing math tossing a zero in makes all things zero (or unanswerable…divide by zero). But we have ONE we know for certain. That changes the math and it is very unlikely, given the size of the universe and all that is in it, to suppose our planet is the only one. Possible but mathematically unlikely. Very unlikely.
This is quite possibly true.
(bolding mine) You’ve arbitrarily assigned the odds as “astronomically unlikely”. We don’t know that.
I’m not disagreeing that there are probably other lifeforms out there. I’ve stated several times in this thread that I do. But we can’t know how rare it is or might be without knowing the odds of life arising. I’m pushing back against those who are postulating there are millions, of million years of ETIs that are whizzing around our galaxy like Star Trek.
A subset of one tells us only that it happened once. Show me just one more and I’ll concede ubiquity.
If you REALLY want to dive deep into this check out the Anthropic Principle.
That will bend your brain for a while (but it is interesting). Not exactly on point but I think adjacent to it in an interesting way.
I’ll check it out, thanks for the link!