With billion planets out there, it seems almost impossibly unlikely that Earth is the only one with any sort of intelligent life on it. I picked thousands.
How does life originate at all, though? Unless we can answer that, we can’t make a rational guess about how much, if any, other life could be out there. If there was another planet that was nearly identical to Earth in terms of atmosphere, sun, orbit, etc. does that mean there would be any life on it? How can life come out of inanimate matter?
For the record, I voted that we’re alone in the universe. To think otherwise strikes me as wishful thinking, at best.
Why are so many posters having trouble with the concept of this tread? It’s simple, we don’t know but the OP wants our gut guess.
If by intelligent you mean self aware/abstract thought I vote a rather small number. A handful at best. Life takes a while to become self aware and the universe is a violent place.
We have some good ideas about how life likely started, but haven’t yet been able to start abiogenesis in a lab. I’m sure many biologists are still at it trying to crack that one.
Anyhow, whatever the conditions might have to be, it could be a huge set of variables that make abiogenesis astronomically (heh) unlikely. Or there could be wide range of variables that’ll work to kick-start a replicating molecule, then evolution takes over.
Consider the Milky Way has around 200 to 400 billion stars. If each star on average has 5 planets you’re talking roughly 2 trillion planets in this galaxy alone at the max (more or less). That’s an ungodly amount of natural lab space to allow nature to do its thing when it comes to creating life.
Well, because of this: When you look at the night sky, at least some of the stars you see may no longer exist.
Still all things being equal, I’d say in our galaxy maybe between 10-100 for any given 1000 year period. Picked because I’m a hopeful space junky, no particular scientific rationale other than the sheer number of stars.
Based on this, I answered thousands, but the only number I really would be shocked by would be “1.” ETA: Well, I guess millions and billions would surprise me, too.
I’m an optimist. Not about intelligent life elsewhere – I have no idea if they’re out there or how many there may be. But about our future.
One way or another, there will be intelligent life throughout the galaxy eventually. It might take millions of years, but humans and/or our descendants (and perhaps our technological ‘descendants’ in the form of AIs) will colonize the galaxy, and possibly even other galaxies.
We won’t necessarily need faster-than-light travel to do so – even if we never develop cryosleeper ships or generation ships, there’s another option:
Seedships. The biggest problem with spaceships is all the mass for people and life-support- food, air, water, recycling, etc. So we eliminate that. Load up automated robot ships with genetic material (and life forms that can be frozen or otherwise suspended, like seeds, bacteria, etc)- and send them out on their way towards various star systems that may have earthlike planets. Then the robot ships land on a world with some water and whatnot, and start an accelerated “evolution” program- first seed the soil and atmosphere with microorganisms. After a few years (or dozens or hundreds or more- there’s no hurry), when the soil and atmosphere is at a certain level, the robots start planting the plant seeds, along with fertilizing the bee and ant eggs they’ve frozen, and work their way up- when the conditions are okay for the next “level” of seeding, create and release those animals (fish into the ocean, insects/amphibians/reptiles on land, etc). Sort of simulate the biological history of Earth, thus creating a new ecosystem in the time frame of perhaps hundreds or thousands of years- as weird and different as it undoubtedly will be as it evolves to these unique conditions. The robots can stop at the point that the baby animals need a mama to take care of them (so no birds and mammals, probably). And the final step will be fertilizing the stored human eggs with the stored human sperm, and having soft, furry robot mamas feed the babies formula, talk baby talk, and play them videos from the now extinct human culture to teach them language and human interaction.
And so after the thousands of years or however long, the first humans in millenia will awaken to a new planet, to frolic and build a new civilization, and experience new and interesting psychoses brought about by having been raised by furry robotic mothers and not people.
This only needs to happen a handful of times every million years for humanity to spread throughout the galaxy, eventually.
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The universe is a big place, but unless FTL is possible most of it may be forever beyond our reach, other than maybe detecting powerful artificial signals. The OP asks just about our galaxy, which is a lot smaller.
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The big, big question is how common is abiogenesis. We’ve taken for granted that it’s virtually inevitable anywhere liquid water and organic molecules coexist- but is it? I for one hope to live long enough to see the solar system explored for subsurface aquifers of liquid water, on Mars, Ceres, and the outer planets’ moons. If we find liquid water but to our astonishment it turns out to be sterile, the Drake Equation will take a huge hit.
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How likely is life to endure if it does start? Do many planets get blasted back to the Hadean level by periodic bombardments? Do planets get repeatedly sterilized by gamma-ray bursts or supernovae? Is our solar system unusually stable, and most planets wander too close or too far from their stars for life to survive? Did Earth require a narrow, specific set of geological events for life to develop beyond a primitive precursor form?
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How likely is advanced life to develop and endure? Does life exist but most of it is single-celled, or the equivalent of jellyfish and flatworms? Is a high-oxygen atmosphere necessary for advanced life to have access to enough energy? As far as we know, there’s never been a species large-brained enough to be intelligent until recently in geologic terms. Is behavior above the instinctual level rare?
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Does self-awareness and advanced problem solving ability ever advance beyond an animal existence? Are humans unique in combining intelligence with tool making?
I voted “one” even though I might be wrong because right now it seems within the realm of possibility that that’s the case, and we have no direct evidence otherwise.
Abstract thought seems like an awfully high bar. You wouldn’t call beings who were as capable and self-aware as a seven-year-old human intelligent life?
I went with 100s of thousands. Ask tomorrow, I may have changed my mind again.
The whole Goldilocks Principle sort of makes sense, but you have to kind of want it to make sense. It’s not my favorite theory. Everything had to be juuuust right! Seems awfully anthropocentric to me. I don’t think Earth is that special. Our sun isn’t that special. Stars, rocky planets, water & organic molecules of all kinds abound. Solar systems are full of good life-making stuff.
Last I read there are about one billion earth-like planets in our galaxy, and that’s conservative. Add in all the moons and even conservatively we’ve got billions and billions of candidate worlds.
Every planet is a unique little snowflake I guess, but at the same time I don’t think the universe does rare very much. Everywhere we look it’s pretty much the same stuff over and over again. Galaxies, stars, planets, moons, asteroids & comets. It’s all the same stuff, all over the place. If we aren’t really that special, then intelligence probably isn’t that special either.
I largely agree with Dracoi. And if a difficult ocean-to-land transition was necessary, how much does this owe to the high tides caused by the large Moon? – These tides were even higher half a billion years ago.
Although the number of Milky Way-sized galaxies in the observable universe – about 100 billion – may seem a pittance compared with the uncertainties in Drake’s Equation, I’d have picked much more than one if the question were about the entire such universe.
I mean, for the sake of simplicity, keep the definition as loose as possible, but also keep in mind how a dog or dolphin is intelligent, yet there’s a profound and intangible leap between them and us. It’s an important, but a fuzzy distinction. It’s those that have crossed that sort of gap in intelligence I’d like for voters to keep in mind as the “definition of intelligence”.
Things like technology and economies and governments don’t need mentioning since I thing a lot of that kind of stuff is a side-effect of this profound intelligence leap. We can argue all day about what does “intelligent” mean in terms of alien species, so just keep those loose terms in mind to whatever degree to hazard your guess.
As per your 7 yo girl example, yes. She meets the criteria, but try not to think in terms of individual circumstance (e.g. a severely mentally impaired person, etc.), rather the potential and capacity for the species to achieve maximum intelligence.
This is actually a facinating phenomena, and demonstrably so, on an episode of Brain Games I watched not log ago in guessing how many gum balls (it was thousands) were in a HUGE gumball machine. They asked a group of twenty people from all walks and ages to take a guess.
When the guesses were averaged, the number was astoundingly close to the actual amount. Yet the guesses ranged from the obvious low and ridiculously high, with a few reasonable guesses mixed in.
Now, granted, the had some real, visible data to work with (however, so I don’t know it would apply, but it’d be interesting to tally the poll numbers after a good number of votes.
When we’re talking about intelligent life, though, the number of labs is only relevant if we assume that they do not interact.
If interstellar travel (if only by automated self-replicating probes) is possible, then it’s entirely likely that intelligent life on a galactic scale is a lot like single-celled life on a planetary scale. That is, once you have your first protobacteria, it takes over every niche so quickly that there’s no time for a second abiogenesis to occur. The first life form on the stage dominates the environment and prevents a second life form from coming about independently.
An intelligent life form can go from stone age to space age to pan-galactic in a tiny fraction of the time it takes to go from single-celled to multi-celled. So the first intelligent species could effectively prevent the independent rise of others by filling up all the galactic niches first.
I suppose this is not quite as inevitable with intelligent species as it is with the first bacteria, but it seems pretty likely to me. And in that case the answer to why we’re the first/only is that a runner-up-Earth would be populated by the other guys’ robots rather than by us.
Die, Kilrathi scum!
According to the 84 votes we’ve polled, here’s the average as broken down below:
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One, Just Us. 30 people think it’s 1 = 30
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A few. 4 people think it’s ~5 = 20
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Dozens. 8 think it’s ~48 = 384
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Hundreds 8 people think it’s 100 = 800
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Thousands 18 people think it’s ~1000 = 18,000
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Hunds of Thous. Six people think it’s ~100,000 = 600,000
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Millions. Six people think it’s 1,000,000 = 6,000,000
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Billions. Four People think it’s 1,000,000,000 = 4,000,000,000
**30 + 20 + 384 + 800 + 18,000 + 600,000 + 6,000,000 + 4,000,000,000 ÷ 84 voters = **
Which give us a “Wisdom of the Crowd” estimate of 47,697,848 intelligent races within our galaxy alone.
Of course, it’s pretty meaningless as it stands, but it’s food for thought… 47.5 million out of around 1 to 2 trillion planets. Hmm…
Are you sure that’s the right way to weigh the responses? If I were to say all 100 billion solar systems in our galaxy have one planet with intelligent life, wouldn’t that skew the results badly? Surely the peak of the bell curve of the answers would be closer.
I’m not sure at all. I just went with my amateur guess as to how to average the results.
Anyone is welcome to take a better shot. This is NOT my forté! 
Oops, wrong question.
To the OP, I voted “one” if we’re talking about organic life at least somewhat similar to us. When you look at all the conditions on Earth that enable us to exist, it seems to me that the odds of replicating them all somewhere else are astronomical(!). Besides distance from a star, there are equivalent Goldilocks zones for amount of oxygen in the atmosphere, heat retention, tectonic activity and magnetic field, to name just a very few. If any one of those fell outside the parameters that support life, we wouldn’t be here.
If these conditions are created, life seems almost inevitable, going by Earth’s example. But my gut feeling is that finding another planet with that combination of conditions is highly unlikely.
I think a better example would be hiding the jar so that you can only see one gumball, and guessing how many others there are. It could be a thousand or it could be none. There’s no way to know.