In my opinion, the excitement occasioned by the discovery of so many exoplanets has clouded our collective judgement on the Fermi Paradox, leading the overwhelmingly most probable resolution to be underemphasized.
Namely: there is no life out there. Not due to baroque mechanisms such as techno-self-destruction but just due to its sheer unlikeliness. As large as the number of stars in the observable universe is (let’s say 10^24?), the space of combinatoric possibilities that must be threaded for the sustained chain reaction of life to occur is probably that much vaster. The so-called Drake equation is not useful since multiple terms have error bars that are not even estimable.
I think the probability of there being other life is much closer to 100%. There just has to be. Our universe offers way to much of the correct “stuff” that can create life that it just has to exist elsewhere.
Why haven’t we seen it? Well that is one of life’s great mysteries.
But the idea we are all alone in this giant thing called the universe… it just doesn’t feel right. The more we learn about things the more we realize humans aren’t really special and neither is our planet. Hell the idea that there are other galaxies is a concept that was only realized around a 100 years ago!
We humans think we know a lot but the truth is there is way, way more stuff we don’t know.
I think life's probably fairly common. Like, bacteria-type stuff, maybe something like moss.
I think complex life, and life that lasts as long as that on Earth has, is probably extremely rare.
There's a lot more that's special about Earth that lets it support large fauna over long spans of time, than just orbital position and basic composition and such. Our weird moon plays a role, tectonic activity is vital, not just for our radiation shield but for the carbon-silicate cycle, Jupiter may even play a pretty big role, and so on. A whole bunch of systems are required to keep conditions on the planet from running away in one direction or another, and it's still come close to getting stuck in some hostile-to-life state, multiple times.
If you grant moss and bacteria, then more complex life forms become inevitable. There are _advantages_ to be being multicellular, or multicellular life wouldn't exist. It's energetically advantageous for a plant to acquire a woody stem and stand up above the moss, or for a simple organism to work out how to have eyes, or teeth, or legs, or an exo- or endoskeleton. Assuming an environment that affords nutrients and is stable over a long time, once life kicks off it should keep complicating itself. It wouldn't stop at simple forms.
I fear that "much close to 100%. There just has to be" (as much as I too would like to share in this sentiment) may be an anthropomorphic projection and wishful thinking. Anthropomorphic because we are living creatures and assume that there must be other living creatures in the region of the universe we can see, even if just biochemically.
But, one thing we are able to estimate is the number of stars in the observable universe -- that collection of stars in causal contact with us. It is far from infinite. In fact, not that much larger than the number of atoms in a macroscopic chunk of matter. The number of possible games of chess is incomparably vaster.
If by "universe" we mean everything out beyond our causal horizon in an infinite universe, then I would guess that yes, there is other life. Actually, there are other copies of you too, because everything that can happen does happen in an infinite universe. The hinge of my point is that the observable universe is not infinite.
This is not to say, by the way, that we should not continue looking for traces of life or to be open to these.
I do not think so. We know nothing. We really cannot answer if there is life out there or not at our stage. Not until we figure out the loads of problems hampering our very ability to *start to answer the question in earnest. Not to say our efforts thus far do not count as they do.
My point is we do not even know with certainty if life rose on Venus or Mars within the known scope of time we think has passed as an example. That is a question we could for sure answer in the next 100 years with relative certainty. I would hope we could in any case.
And once we get to the point of answering that question.
In my personal opinion -- of course there is life out there in the universe. It is too big and vast and has presumably been around for too long for us to be the only ones.
Sure the universe is crushingly vast compared to our small bits and pieces of knowledge. But so is our imagination. Whether it is a Hollywood set of a sci fi show or a astrophysicist rolling through endless equations; one day we just might find the answer.
This is one of those things we will not know about until we do.
True that we know little and actually this is my point. I fear that "of course there is life out there in the universe" (as much as I too would like to share in this sentiment) may be an anthropomorphic projection and wishful thinking.
One thing we are able to estimate is the number of stars in the observable universe -- that collection of stars in causal contact with us. It is far from infinite. In fact, not that much larger than the number of atoms in a macroscopic chunk of matter. The number of possible games of chess is incomparably vaster.
This is not to say that we should not look for traces of life. That is a completely separate question.
I don't think people realize how quickly EM radiation falls off with distance, and how large the scale of "transmitters" would need be before we could detect.
Today we can finally, barely detect massive planets occluding suns, and we can only do this in our neighborhood of this galaxy.
Modulated communication from a source not at planetary scale is currently impossible for us to detect.
We need something much much bigger than the Arecibo telescope (RIP).
Arrays of coherent antennas can achieve gains equal to their total aperture, but spacing them out far apart does not help for communication receiver gain G/T. That technique only gives better angular resolution for imaging.
I also suspect that in time we will discover new mediums of communication that have better properties than the electromagnetic spectrum. Maybe when we listen on those mediums there will be a ton of chatter…
Within EM, gamma rays (highest frequencies) may be able to achieve sufficient spatial directivity for interstellar communication, but we'd have to be very lucky to have a beam pointed at us. Also currently our gamma ray receivers suck, and they have to be in space because our atmosphere largely blocks it.
On the other hand all those tech developments you pointed out we’ve only discovered and utilized in the last 100 years. Now imagine a civilization with 10 times that experience/time
Then you need to explain how life on Earth started a short period after it cooled down. Yes, it took a long time for complex life forms to emerge but life itself started right off the bat.
This may just mean that IF life is to originate, it will do so shortly after a solar system forms, or not at all. To infer that the early OoL means OoL is easy has the implicit assumption that the probability of OoL would remain about constant over time.
Easy to look up! By current estimates Earth cooled enough to have liquid water about 4.46B years ago and the first RNA emerged around 4.35B years ago. So it took just over 100 million years for simple forms of life to emerge.
Ok, so you are setting the scale as "from the present conversation back to formation of Earth" and saying that this is large in comparison to "from formation of Earth to formation of RNA". However, I respectfully don't see how this scale has any bearing on the probability of life forming around another system. Formation of life is certainly a prerequisite to the formation of intelligent life (the two events in question). Both could have a probability of occurring much smaller than 10^-24 (approximate # of finite stars in observable universe).
There is a pitfall with this line of argument in that it is appeal to intuition in a domain in which we have none, because we have no ability to intuit about large numbers.
That doesn't mean that it's wrong (though I myself think that it is); but appeals to "sheer unlikeliness" should be made with care because they can rely on facts such as "the chance for a given star system hosting a planet on which even simple life emerges is 1 in 10^X" hence "oh my 1 in 10^X is a very small number!". Where what matters is e.g. how that number compares to the number of such star systems. Etc etc.
Predictive value aside, the Drake equation at least attempts to quantify.
For a long time we weren't at all sure whether the expansion of the universe would stop, leading to a "big crunch", or continue forever, slowing down for eternity. Then we found the other option appeared to be supported by observational evidence: the expansion is accelarating.
We're in a similar position with finding life elsewhere. The vague error bars in many terms in the Drake (so-called) equation shouldn't be read as indicators of (im-)probability, more as signs of major gaps in our understanding. We slowly inch towards better data. Surprise is likely on the journey. I would say though that, so far, we're pretty sure there is some life in the universe, but nothing else.
Yes, we know little (aside from the finiteness of the observable universe, which is known at a quantitative level). I am curious why then you say "so far, we're pretty sure there is some life in the universe, but nothing else." I fear this may be anthropomorphic projection and wishful thinking.
In a hypothetical total universe timeline of something like 100 trillion years, say till the degenerate era...we're not really very far in right.
If we were near the end and had the same paradox I'd say you're probably right in that the answer is there is no life.
But we're really really early, so either we're a total fluke and the first or there's another reason.
Basically what I'm saying is if you're right and the probabilities are so low then I'd think we should either not exist or the timelines I've sketched are very very off
If you look at the wikipedia's list of 100 nearest stars, only 4 are single main sequence stars: Tau ceti, Sigma Draconis, 82 G. Eridani, Delta Pavonis. All other are either binary stars with unpredictable orbits or flare stars. Stars where civilizations can quietly mature are rare.
Or they're not communicating using EM. And maybe they can't get off planet. And maybe the mean distance between pairs of civilizations is so large that interstellar travel is just not practical at all for any of them and us as well.
If it’s vanishingly unlikely, but space is incomprehensibly huge and time is vastly long, then it happening exactly once is extremely improbable. 0 times, believable. But those probabilities yielding 1 life event must mean 2 life events is also possible, no? Or 3? Or 100? Why so confident it’s exactly 1?
All that's required to explain the Fermi Paradox is that it happen < 1 in an observable volume of the universe. The volume of the universe in which OoL could happen could be vastly larger, but we could never see most of it. Each extremely rare occurrence of intelligent life would never be able to contact any other, as they'd never be causally connected by signals traveling at the speed of light.
How is this the biggest mistake? So far it does appear to be the case. What negative consequences have come of believing ourselves to be unique? We have yet to find, on our planet or elsewhere, any creatures that build complex systems out of dead things.
He's engaging in a kind of ad hominem argument, that believing we are unique is a morally questionable position, therefore we must believe otherwise.
The errors in history have been the opposite: believing other intelligences are more common than they have turned out to be. The world was filled with non-human creatures in mythology and folklore. In the 1700s it was presumed every planet in the solar system had intelligent life on it.
How would your perception change if life was discovered on the moons around Saturn and Jupiter? Does that increase the likelihood of life outside our system?
If it was biologically similar to Earth life, it wouldn't prove much of anything, as it could have gotten there by impact panspermia.
Discovery of a fundamentally different biology, even on Earth, would indicate two OoL events had occurred near each other. This would be very strong evidence that OoL cannot be rare.
Here is a plausible alternative scenario. As planets form, there is a certain window of opportunity where conditions are right for life to get going (among other extraordinarily unlikely accidents that must come together, the phase of planetary evolution must be just right). Almost always, this too fails. After all, every attempt to date to recreate primordial conditions in the laboratory have failed to produce any life.
I return to the key point: the number of planetary systems in our observable universe is not infinite. It is not much larger than atoms in a macroscopic chunk of matter. It is entirely possible that the probability of life forming on a given planet is much too small for it to have happened in the last 13.7 billion years. This is just like the fact that the probability of radioactive decay of an atom (even in a sizable sample) becomes unlikely if the half-life is too long compared with the time scale of observation.
Namely: there is no life out there. Not due to baroque mechanisms such as techno-self-destruction but just due to its sheer unlikeliness. As large as the number of stars in the observable universe is (let’s say 10^24?), the space of combinatoric possibilities that must be threaded for the sustained chain reaction of life to occur is probably that much vaster. The so-called Drake equation is not useful since multiple terms have error bars that are not even estimable.