Earlier quoted context omitted.
If we're talking about galactic distances and timescales I don't see why we couldn't safely assume enough technological advancement for either aliens or humans to modify their own biology to the point where centuries would be a small fraction of your total lifespan. I think the bigger question is why any significant number of people would travel to more than a few star systems if you had to do it slowly. If the syste…
If the Internet has told us anything, it's that as soon as the production of a self-replicating probe becomes accessible to a hobbyist, some people will do it even if there's no benefit to them. And it only takes one. The far future human colonists won't be landing on unspoilt wilderness; they'll be reclaiming systems from some 25th century script kiddy.
The Fermi paradox revisited: Technosignatures and the contact era
201–210 of 353 posts
Re: The Fermi paradox revisited: Technosignatures and the contact era
#202The Fermi paradox assumes that "intelligent" is one threshold, and we are beyond it. We couldn't communicate with the most advanced primates from a million years ago. A civilization a million years past ours would be unlikely to want to talk to us. The average star in our galaxy is a billion years older than our sun. You can only communicate with civilizations near your level, which are inherently much rarer. We aren…
So a fun thing to try to think about is "What's missing from our intelligence?"
Our brains may just be made up of lumps of neurons, but we can break out various capabilities we have:
* language * tool use * memory * ability to think about hypothetical situations * ability to think about abstract concepts * theory of mind
We can think about what alien creatures or civilizations are like that lack them. A civilization without tool use, a civilization without language, a creature with no memory.
But thinking about capabilities we don't have is really hard, because, you know, if they exist, my brain isn't equipped to think about them.
I can think about having a perfect memory, or being able to think about N things in parallel, or being able to learn things by directly copying the information to my brain. Are those good enough to be new capabilities, or are they just minor variations of the capabilities I already have?
Re: The Fermi paradox revisited: Technosignatures and the contact era
#203Earlier quoted context omitted.
Our signal for oxygen and other bio-signatures is so much stronger than the signals we have been sending recently and it's been going out for...quite some time.
Maybe they found Earth already and they just find it boring: "yet another planet likely filled with idiots"
I mean, the Great Oxygenation Event is ~2 billion years in the past, and the Cambrian Explosion is only half a billion years ago. If intelligent, space-faring aliens checked it out, there's a 75% chance they arrived while the most interesting thing on Earth was, well, I can't think of anything that wasn't "technically before the Cambrian but like, only by 50 million years". Fungi?
We should look for oxygen-rich atmospheres, but we need another signal before we jump in a rocketship and go looking for someone to talk to or eat.
Re: The Fermi paradox revisited: Technosignatures and the contact era
#204Earlier quoted context omitted.
We are actually running out of places in our history to fit a great filter. Most of the events in our evolution seem probable, even inevitable. In fact the only place IMO that's really left is the emergence of the first self replicating RNA molecule. But even that seems too probable to be a great filter. And if its not behind us, it has to be in-front of us or we are under a great misapprehension about the nature of…
BS. Filter 1. If we had no large moon, roughly every 30 million years or so our axial tilt would become too extreme for life. We do not have another example of a planet with a moon to rival ours in relative size. Filter 2. Without Jupiter acting as a cosmic vacuum cleaner, we'd predictably be hit by enough asteroids and comets that we'd never have evolved. In thousands of solar systems that we've found, we've found l…
But it comes back to the number of chances. To wit, there's approximately 200,000,000,000,000,000,000,000 stars in the universe. We might be that one in a 200,000,000,000,000,000,000,000 shot where it all came together to create life but it's rather improbable. Almost certainly is other life out there.
Re: The Fermi paradox revisited: Technosignatures and the contact era
#205Perhaps I'm missing something, but this seems to get the Fermi Paradox backwards. It explains why we haven't been visited by aliens (the light-cone of our radio transmissions is small and therefore aliens outside of it couldn't send probes to us), but the key observation of the Fermi Paradox is in the other direction; why can't _we_ see _other_ civilizations, in all of the billions of years of history in our light-co…
> [The Fermi Paradox] explains why we haven't been visited by aliens (the light-cone of our radio transmissions is small
I usually hear the Fermi Paradox brought up in opposition to the reasonable-sounding null hypothesis of "life is common but stars are far." The argument goes that technological development and galactic colonization should be a very fast process (millions of years) compared to variation in nucleosynthesis/abiogenesis/evolution timelines (billions of years). In other words, if the story of the Milky Way were an hour long movie, the Milky Way would transition from empty of life to full of life inside a few seconds, and landing at the half-way point of that transition would be an unlikely feat of synchronization. That's why Fermi Paradox speculation often doesn't distinguish between "waiting for a radio transmission" and "already here" -- the transition should be very fast on geological timescales. Aliens wouldn't stick in "waiting..." for 100 million years, they'd eventually send colonists to grab the free real estate.
In other words, I don't think it's a mistake that the article repeatedly threw in the caveat "unless civilizations are extremely abundant" because that would be a common objection to its thesis.
> if you fix the Drake equation, the paradox dissolves
Yes, it's possible to toss enough uncertainty into the equation to raise the probability of low N significantly above 0, but the whole idea of FP is that you have to work curiously hard to make this happen.
Re: The Fermi paradox revisited: Technosignatures and the contact era
#206The Fermi paradox is good for a nice chat at a party. But it's not a paradox at all. Imagine there's an alien civilization in our galactic neighbor Proxima Centauri. How would we know they are there? To make it more plausible. Let's say we figure out a way to send a space probe to Proxima Centauri. How do we communicate with that probe? Easy, you say, just like we communicate with the Voyagers: they point a reasonabl…
Well said. The "Drake Equation" is complete and utter garbage. There is no such thing as a "probability" of any of those terms, in the way we normally understand probability, i.e. dice or card games. That said, there probably are intelligent civilizations somewhere in the universe, but we have that pesky problem of distance and the speed of light, as you said. People like to imagine that eventually civilizations find…
> There is no such thing as a "probability" of any of those terms...
> That said, there probably are intelligent civilizations somewhere in the universe
...pick one :-)
Re: The Fermi paradox revisited: Technosignatures and the contact era
#207Earlier quoted context omitted.
It routinely bothers me a bit that, IME, most IRL discussions of the Fermi paradox tend to omit this rather simple explanation. Half the time it's brought up, FTL is offered as the solution. Which as best we can tell is fundamentally impossible. That squishy or otherwise organic bodies are generally unable to travel interstellar distances has always seemed to me to be the simplest solution. Assuming intelligent life…
Even with FTL you have to know where to go. Let's say you do 100 solar systems per year (going somewhere close to the star and some local jumps to look around.) There are 100 billion stars in the Milky Way. It takes a billion years to sequentially scan the galaxy. Optimizations in the search algorithm to cut that number down to 100 years are left as an exercise ;-)
Branching factor of two means around 30 hops to visit every star.
Re: The Fermi paradox revisited: Technosignatures and the contact era
#208The Fermi paradox is good for a nice chat at a party. But it's not a paradox at all. Imagine there's an alien civilization in our galactic neighbor Proxima Centauri. How would we know they are there? To make it more plausible. Let's say we figure out a way to send a space probe to Proxima Centauri. How do we communicate with that probe? Easy, you say, just like we communicate with the Voyagers: they point a reasonabl…
>How would we know they are there?
How about pointing an optical telescope at them to take a look?
Direct Multipixel Imaging and Spectroscopy of an Exoplanet with a Solar Gravity Lens Mission
Re: The Fermi paradox revisited: Technosignatures and the contact era
#209The Fermi paradox is good for a nice chat at a party. But it's not a paradox at all. Imagine there's an alien civilization in our galactic neighbor Proxima Centauri. How would we know they are there? To make it more plausible. Let's say we figure out a way to send a space probe to Proxima Centauri. How do we communicate with that probe? Easy, you say, just like we communicate with the Voyagers: they point a reasonabl…
We've been able to fly or emit radio signals only for a bit more than 100 years. If there exist any other civilisations and we assume they start independently, there should be ones that started billions of years ago. Which is enough to visit entire galaxy even at very slow speeds. The paradox is that we are not seeing any signs of any other intelligent life.
If they visited us a billion years ago, would we know?
Time is as big as space. If you’re positing that aliens must exist and can explore, they might have just done that and lost interest a million years ago, or they do sweeps every hundred thousand years.
Re: The Fermi paradox revisited: Technosignatures and the contact era
#210Yeah, this is where I've landed on Fermi. It's very likely life exists elsewhere - possibly even on moons in our solar system. And it's somewhat likely intelligent life exists in other solar systems. But physics is such that it is much less likely two intelligences will be able to talk to eachother much less reach eachother. To quote Douglas Adams: Space is really big. You just won't believe how vastly hugely mind-bo…
It routinely bothers me a bit that, IME, most IRL discussions of the Fermi paradox tend to omit this rather simple explanation. Half the time it's brought up, FTL is offered as the solution. Which as best we can tell is fundamentally impossible. That squishy or otherwise organic bodies are generally unable to travel interstellar distances has always seemed to me to be the simplest solution. Assuming intelligent life…
It routinely bothers me a bit that, IME, most IRL discussions of the Fermi Paradox settle on this rather simple explanation when the whole idea was that this "simple explanation" was extremely unlikely, pushing speculation to more complicated and interesting hypotheses.
Emergence of life on Earth took 13.7 billion years, galactic colonization should only take millions of years. We should not expect to find the galaxy half-colonized, as this would be a staggering feat of synchronization. We should find the galaxy completely full or completely empty. It seems to be completely empty.