All available evidence at the moment says one. We don’t really know every factor needed for a planet to reach the level of intelligent life, but even with long is, the number ought to be higher. I’m hopeful that with further research we can find a neighbor or two in my lifetime.
I tend to be pessimistic on this one. Here are some of the key break points and what I think about them:
Origin of life: it appears to have originated fairly quickly. Some people think perhaps more than once, being obliterated by large impacts early. Lots of scientists think that you’ll find life essentially anywhere that life could be, and that is true for Earth. Now, I may not be so personally convinced (since the evidence is certainly lacking) but maybe I’ll give this one a pass and say that some form of life is pretty common. Anyway, we had life in some form within 1 billion years from the Earth existing, and withing perhaps just hundreds of millions from when it could have supported life.
Multicellular life: it took, what… 2.5 billion years to get the first multicellular life? So it’s obvious that even getting beyond a single cell is a massively complicated and/or unlikely event. I find it particularly noteworthy that this 2.5 billion represents about 40% of the Earth’s total potential for sustaining life at all.
“Organized” multicellular life: you don’t get bilateral symmetry or vertebrates for another 500 million years, so even multicellular life spent a lot of time in the “blob stage.” I don’t think organization itself is so necessary to intelligence, but being land based probably is necessary. Life makes it to land within tens of millions of years of being organized.
From those first land forms, we’re 200 million years from mammals and dinosaurs, and that’s really the first time you could have had intelligence.
Once you do have intelligence. it’s 10,000 years from the first farm to taking closeup pictures of Pluto.
Even if we accept the speed of light as an unbreakable speed limit, does anyone really think it will take us longer than 10 million years to explore the galaxy? (That’s an average speed of 1% light). Von Neuman machines, or whatever, if not actual humans.
So… what I see are two major break points: getting to multiple cells and then getting to some kind of body organization. These took billions of years to develop.
During those billions, you’re rolling the dice on major impacts. There are impacts bad enough to throw off the entire crust of a planet and that would start you back at square one. Earth won’t exist long enough to do this a second time.
But once you get past those crucial breakpoints, a virtual blink of an eye has you everywhere. Maybe it’s premature to say that we’re totally alone in the galaxy, but I think the evidence at least supports the statement that we’re first.
And if we decide that we’re first, I’m not sure why that is, but at the very least I can answer the poll with “1”. It doesn’t matter whether we’re just first or truly alone. The only other option is that advanced aliens are just really sneaky and only visit us because of their anal probing fetish.
So, yeah… put me down as thinking we’re it.
Great breakdown, dracoi.
I do find it interesting, however, that the option “we’re alone” is taking 40% of thinking so far. Is this do to that actual belief that it really is only us, or that we can’t know—so they just vote for that?
I voted for a few, but was strongly leaning towards none but us.
My reasoning is mostly the same as those specified by dracoi. With the added fact that I am not sure that intelligence is a long term survival strategy. Given what we are doing in terms of the environment and the lethality of our weapons, I have a hard time imagining us still being around in 50,000 years, much less a million. So while there may have been a few winks of intelligent life here and there, they are probably not overlapping with us.
All of them.
They’re having a party.
Jimmy Carter is passed out on the couch.
To get to where we are now involves negotiating such an endless series of obstacles, fortuitous happenstances, and other life-rending/preventing events that if we truly were able to drink in and truly grasp all of the factors involved that it would truly beggar our imagination and humble us to the core.
Not only do I think that we are the only technological race in the galaxy, I think there is a sufficient chance that we are the only one in a 100 million light year bubble.
Is there life elsewhere in our galaxy?
I am almost certain that the answer is yes. Life will arise almost anywhere that the conditions are met. I think that life is a basic,fundamental property of our universe. We don’t even know what the minimum conditions are, except that there is life almost everywhere on Earth even in very hostile conditions. I feel that it is a given that we will find life of some sort in our own solar system, perhaps in multiple spots. There may even be non-water dependent life.
**What do we mean when we ask, is there intelligent life? ** Dolphins are pretty smart. So is my cat. They have no need for any sort of tools or technology. There may be many life forms of this nature. But what we are usually talking about is tool using, technological, space-faring life. That may be very rare.
Some planets where life may exist will have continual cloud cover that inhibits the awareness of the stars. Some will be entirely water worlds with no land at all. Some life bearing planets will be incased in an icy shell. Some rocky worlds may only support life deep underground. These and other conditions will limit the imagination should intelligent life exist there, no dreaming or curiosity about the rest of the universe because for them it does not exist. Other planets that may support intelligent life will have such a strong gravity well to escape from that the energy, even if there is technology, the energy to escape the planet is just not available. And then there is that whole technology thing.
When we wonder about intelligent life we usually are thinking about life like us. Technological, space faring, tool-using, curious, want to meet the neighbors, type beings.
The common trope is that we must be a very young technological civilization and there just has to be beings far, far advanced beyond our little attempts. So far advanced that we would not even recognize them, or they us. Ancient Aliens. The Elder Race of the galaxy. I just do not see this at all. It has taken several generations of stars to create the elements necessary for life here. And several billion years for that life to result in US. Sure, other areas could have met the conditions sooner.
To think that we are the newbies just waiting to be contacted by the many other, more advance technological entities in our Milky Way is just too much Star Trek fantasy.
We humans, are the Elder Race in the Orion Spur of the Milky Way. Millions of years from now, should we still exist as a species, this will still be true.
Maybe this question falls into the Wisdom of the Crowd category. Nobody *knows *the answer, but if you average the answers from a large and diverse population you may get a pretty good number.
That. It sould be an option. I see no reason to pick a number rather than another. I’ve no “best guess”.
My feeling is, truly, “I don’t have the slighest clue and picking a number would make no sense”.
^ Agree. Just us - and at the rate we are going it’s not likely we’ll last long enough to know otherwise, unless we start taking real and immanent threats to our existence seriously.
I actually considered making that a poll option, but I wanted to force a guess. We already know the answer is “We have absoluty no idea, no data (except one) and no way to tell in the forseeable future.” This is all about a guess on what you know on the topic.
Billions?
*On 4 November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way.[13][14] 11 billion of these estimated planets may be orbiting Sun-like stars.[15] *
AIs could of course inhabit planets irrespective of their zoning suitability for organic life.
I went with “billions” because, why not, eh?
People go on about “ooh, it took billions of years for us to evolve” as if that means anything. Since we don’t have a second sample, we can’t tell if that’s normal, or maybe our planet lacks slood and therefore we didn’t develop intelligence as fast as is galactically normal. With a sample size of one, it’s about as plausible to say we’re particularly slow as to say we’re the norm (or particularly fast). It’s like - “oh, you need a big moon, and a Jupiter, helps keep meteors away” - maybe intelligence needs the meteors, and we’d have been banging the rocks together a lot sooner if there were more of them about…
This.
To me, there’s two variables that need to be filled in to give an intelligent answer:
- Does intelligent life usually or always destroy itself?
- Is intelligent life inevitable once life arises?
I came in here just to say that 
Serious answer, it’s just not knowable with current technology. A problem made more severe by the time/distance factor.
What’s “intelligent?”
If it means being home to a species that has civilization and written language, I’ll guess 1, because of the Fermi paradox. But multi-cellular life that possesses some problem skills, I’m more optimistic.
Just for starters, I’d say self-awareness and the ability to perform abstract thought/logic.
As for Fermi’s Paradox, there could be millions of intelligent aliens right in our galactic neighborhood, but if interstellar travel proves practically impossible, we’ll never know.