Why Any Solution to the Drake Equation is Scary No Matter the Answer

I don't wanna seem to small minded, but you said repeatedly "solar system" instead of "galaxy "

“Two possibilities exist: either we are alone in the Universe or we are not. Both are equally terrifying.” ― Arthur C. Clarke

I've got a feeling that one of the more plausible scenarios that humans meet aliens, is after we send out humans over even 5% of the galaxy, time passes, and we forget where we come from. Then, we find each other again, but by that time we look different enough to not realize we were the same.

Many years ago, I was playing around with Excel and my own version of the Drake Equation. I was trying to predict if there was any possibility of other intelligent life within the Milky Way galaxy, and, if so, what was the median distance between each. To make a long story short, the median distance I came up with was approximately 3,500 light years. This brought up a question to me about how the Drake Equation does not take into account how, even if there ARE or WERE previous civilizations throughout the galaxy, it is VERY likely that we might never meet. This is due to potential differences in the timelines of each of those successful civilizations. I’m afraid that the Drake Equation needs an additional variable. Something like “Galactic Timeline Equivalence”. P.S. The speed of light becomes the ULTIMATE limiting factor! If the nearest of my hypothesized civilizations could spy on Earth from their perch right now, they’d be seeing the Pyramids being built. Thanks for shaking up my brain a bit!

"Once is never, twice is always." Until we see it a second time, we can't assume it has happened. 95% of all galaxies we can see in space are already beyond reach even if we can travel at the speed of light. All of those must be eliminated from the Drake equation. After that, the speed of light and the vast distance between stars mean that we will never interact with life that isn't within a few thousand light years of us. That's pretty much just a tiny fraction of the Milky Way Galaxy, which is 100,000 light years across. If we ignore that the bulge at the center of the galaxy is far more dense than the galaxy where we are and treat the galaxy as a disk of uniform thickness 100,000 light years across and assume we'll accept anything within 5,000 light years (a 10,000 light year diameter disk), then life we may be able to detect and interact with would be limited to only 1% of Milky Way galaxy. Estimates range form 100 to 400 billion stars in the Milky Way Galaxy. Let's go with 400 billion and assume a uniform distribution again. That leaves us with 4 billion stars at most. If we had 9 intelligent races in our galaxy, the odds say we have maybe a 10% chance ever even being able to detect or interact with any of them. Even the closest dwarf galaxy is too far away; Andromeda is well beyond range. This changes if we can find a way to travel and communicate faster than the speed of light. Without that, the odds of there being any intelligent life that humans will ever interact with closely approximate zero. If we manage to detect a second example of even primitive life that didn't originate on Earth, that also changes things. That would mean there's a whole lot of life out there inside our 1% of the Milky Way.

What's wild about the Drake Equation, is that not only are most of the terms unknown, but we could make contact with an alien civilization and STILL not be able to determine many of the terms

I'm more interested in finding life, than intelligent life. Alien ecosystems would be the most amazing thing we've ever encountered ever, and for each intelligent civilization, there must be millions of planets with life. Civilizations on the other hand, seem very very unlikely, given how many billions of species have come before us that never made it to the moon and so on.

Before you move on to cover the Fermi paradox, I recommend reading the paper "Dissolving the Fermi Paradox" by Sandberg, Drexler, and Ord, which points out some often overlooked properties of the Drake Equation that make the Fermi paradox seem significantly more paradoxical than it really is. In short, if you model our uncertainty about the parameters of the Drake equation to produce a probability distribution of the number of communicative alien civilizations in the galaxy, you can see that even if the mean of the distribution is a large number, the probability that there are no civilizations in the galaxy (as predicted by the Drake equation) is still considerable. The paper's abstract: "The Fermi paradox is the conflict between an expectation of a high ex ante probability of intelligent life elsewhere in the universe and the apparently lifeless universe we in fact observe. The expectation that the universe should be teeming with intelligent life is linked to models like the Drake equation, which suggest that even if the probability of intelligent life developing at a given site is small, the sheer multitude of possible sites should nonetheless yield a large number of potentially observable civilizations. We show that this conflict arises from the use of Drake-like equations, which implicitly assume certainty regarding highly uncertain parameters. We examine these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and show that extant scientific knowledge corresponds to uncertainties that span multiple orders of magnitude. This makes a stark difference. When the model is recast to represent realistic distributions of uncertainty, we find a substantial ex ante probability of there being no other intelligent life in our observable universe, and thus that there should be little surprise when we fail to detect any signs of it. This result dissolves the Fermi paradox, and in doing so removes any need to invoke speculative mechanisms by which civilizations would inevitably fail to have observable effects upon the universe." You can find the paper on the arXiv, at arXiv:1806.02404 .

I love exploring these weird gaps in our knowledge. It is both wondrous and intensely humbling to consider the things for which we have no answers. I have a feeling we are quite alone. Perhaps we just need more time to observe and discover, perhaps we will find something, but I find it kind of spooky that we haven’t yet. Then again, space is absurdly Immense, so there’s a lot of room for surprises still. But all the same, it’s just a (pessimistic?) feeling I can never seem to shake.

It seems like no one has pointed this out, us being the only species that has reached all these qualities and from that trying to extrapolate so many variables unknown and impossible to estimate being that we know so little about our surroundings, makes this types of calculations just a rationalization of our imagination.

The first life also has a massive exponential advantage. In the moment a life form forms it instantly is able to use exponential growth. Considering this, anything that doesnt arise practially at the same time should be outdone or outright prevented by existing life within just a few years or decades.

Like always, You break down this subject in a simple understandable way. It is incredibly amazing to play around with the Drake equation. Thanks.

Another key issue is the ability to see light. Dolphins might evolve enough intelligence one day, but their view of the stars is smothered. Imagine how many planets might be oceanic, or subterranean, or have permanent cloud cover. There's also the willingness to extract and use combustible fuels to launch, which inherently began with war. Humans might be the first and only to just discover space itself.

15:41 "We should learn to get along with each other because we are all the life we are ever going to see." - Astrum Profound.

The Drake Equation is a decent guesstimate but it misses several points. For example it only looks at the suitability of the host star but ignores the region entirely. The star in a star system doesn't need to be instable in order for everything to be wiped out by a gamma ray burst or just a simple super nova in the neighborhood. Not to mention extinction level asteroid.

thanks for continually putting in the work Alex.

I personally think that life itself is going to be pretty common in general, at least on the microbial level. We have found organisms living in complete isolation for hundreds of thousands to potentially millions of years underground or under the ice. If microbial life starts on a planet, it would be difficult to sterilize it completely afterwards. Intelligence is probably far rarer, or far shorter lived then expected. And the silence in our neighborhood of the universe does bring me a sense of unease regrading the ability of technological species to overcome great filters 😖

I think that considering life evolved on Earth almost as soon as conditions were suitable, it shows that the evolution of life itself is probably not rare or even necessarily particularly difficult. Of course, we also still don't know exactly how life evolved in the first place, or all of the conditions in which life is possible, so that does introduce some uncertainty, but I think that number is quite high. However, the fact that it took approximately 3 billion years after that for complex, multicellular life to evolve, and several hundred million more years for a species with the intelligence and desire to conquer the world and exploit our resources, says to me that intelligent life is probably extremely rare. Even multicellular life (or whatever equivalent of complex life there is elsewhere) is probably pretty rare. I think it's probably likely that life is relatively common, complex life is uncommon but not necessarily rare, and intelligent/advanced life extremely rare. And the chances that two intelligent/advanced civilizations live close enough together in time and space to communicate is probably even rarer still. In otherwords, I think we're in for a pretty lonely existence. And I have my doubts that settling other systems is even possible in the first place. But that's just my two cents.

I remember this topic came up in a college class years ago and our professor had the most unromantic speculation that, billions of years ago, a race of alien surveyors stopped on a young Earth and emptied its septic tanks before blasting off again - kicking off all Life on Earth. Edit: as in originating all Life on Earth, sorry for the slang

A few things. Regarding the definition for life I wanted to add homeostasis as being another deciding factor, or at least some active way to maintain internal conditions of a body from the environment outside if there is no cell to be had in a lifeform. Another thing is that a lifeform can be even more intelligent than humans and still be unable to make the necessary technological innovations to leave a planet. Lifespan and an ability to manipulate and alter objects enough to make tools and inventions with those tools. It's why octopuses aren't making buildings, because they have incredibly short lifespans despite having the ability to manipulate objects. Dolphins can't either because despite the long lifespan they can't manipulate objects to the point of manking tools and inventions with those tools. In fact I think if elephants had a 2nd trunk and forward facing eyes they would be the only creature other than humans who have a similar chance to make similar technological innovations as humans. And finally I personally believe that roughly 30 intelligent species equal in current human technology will ever exist in our galaxy prior to the heat death of the universe. They won't ever exist at the same time and if they do one would be in its infancy while the other is in its death throes and unaware of what the other will eventually become. I wouldn't be surprised if we find remains of some incredibly ancient alien civilization on some distant planet eventually. Simple life I expect us to find eventually. But something like Star Wars or Babylon 5 that would be a hard no from me as fun as that would be. Maybe something like Dune where the various aliens are really just isolated humans who have become their own subspecies / species. But that's as far as I'm willing to go.