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I just finished the Bobiverse Trilogy. If you haven’t heard of the trilogy it’s a relatively new science fiction series by Dennis Taylor. The premise is that the consciousness of a guy named Bob is put into a self-replicating spacecraft (also known as a Von Neumann Probe), and sent out to explore nearby stars. As I said it’s self-replicating, meaning he can make more Bobs, thus the Bobiverse.
Like most current science fiction it has to grapple with Fermi’s Paradox, and, if I’m going to be honest, it did not do a very good job of this. Now this is not to say these aren’t good books. I thoroughly enjoyed them, they’re a quick, fun read. And despite having some major problems with how he approaches the paradox, he does tackle some other big ideas in an interesting fashion, just not that one. Also, he is not the first to make the mistake I’m about to describe, but he is the example I encountered most recently, so I’m going to be picking on him a little bit. I’m going to call the mistake that he, and others, have made, the “Mistake of Dramatic Timing”.
I’m not going to be able to discuss this mistake without a few spoilers, but I’ll try to keep them as mild as possible. In the books, the Bobs encounter aliens, and as it turns out the tech level of these aliens is basically within a few hundred years of human tech, and perhaps more importantly the aliens were within a few hundred years of encountering Earth regardless of what the humans did. This is the Mistake of Dramatic Timing, and it’s present all through science fiction. I’m sure you can probably think of numerous examples. Though once again, to be honest, I’m not sure I can immediately summon an example as egregious as the Bobiverse. (It’s actually worse than it looks, but I’d have to get deeper into spoilers to explain why, feel free to email me if you’ve read the books, but aren’t sure what I’m talking about.) Which is one of the reasons I felt compelled to point it out.
Hopefully the term “dramatic timing” is descriptive enough that people already know what I’m talking about, but even if that’s the case, putting some percentages to things helps clarify how unlikely it would be to encounter aliens in the exact fashion the Bobs did. Though, for the benefit of those who haven’t read the book, and in order to avoid more spoilers, let’s switch to one of the other examples of this mistake, the movie Independence Day. In Independence Day the aliens are after our natural resources. You can make an argument, given the insane logistics of space that this doesn’t make a lot of sense. Regardless, the point is, with this goal they don’t care if there are humans around or not. In fact it would have been much better if they had shown up 50 years earlier (before the Macbook…)
This means the only reason for the aliens to show up when they did was dramatic. They (and any other potential aliens) could have conceivably visited Earth at any point during its existence. Meaning the chances of them coming during any specific 500 year period (roughly the period from Galileo to the present day, the period during which we’ve actually cared about astronomy) is 0.00001% (500/4.543 billion).
The further probability that when they arrive, their technology will be only a few hundred years in advance of ours, is a little less straightforward to calculate, since it’s unclear whether technology will stagnate, or whether, on the other hand, it will continue to grow exponentially, but either way you’re looking at another very tiny number. For the sake of the example let’s once again use 500 years as our window of matching, and assume a modest average lifetime for a civilization we encounter of 250,000 years (it could in reality be in the billions). If we then assume that they would contact us on average 125,000 years into their existence, then we’re still looking at only a 0.4% chance of having technology that’s within 500 years of the aliens, and a 500 year difference is still pretty bad. I doubt Renaissance Florence would be very eager to fight the US Sixth Fleet. What this means is that the chance of both happening is so improbable as to be effectively impossible. Particularly given how conservative I’m being on the estimates in the differences in our technology.
I’m sure that some people are going to argue that using the entire existence of the Earth as the denominator in our equation is unfair, since there are certain conditions which need to be met before intelligent life could could arise anywhere. In particular most people argue that it’s limited by the metallicity of the universe, and because that takes time to build up (through supernova) and because that limits the number of terrestrial planets on which life could evolve. But as it turns out, terrestrial planets don’t depend nearly as much on metallicity as we thought, In fact, somewhat ironically, it actually appears to have more of an effect on gas giants. The upshot of all this is that we’ve recently discovered rocky planets that are more than twice as old as the Earth. Meaning that life on another planet would have as much time as life on Earth has had before Earth even came into existence. Accordingly, without bringing other factors into play, there’s every reason to believe that there should be civilizations out there which are billions of years ahead of us. Whether it’s exactly 4.543 billion or just a couple of billion doesn’t materially affect the percentages above.
Now of course we know exactly why Roland Emmerich (director of Independence Day), and Dennis Taylor, and all of the others did it, because despite being a mistake it’s a dramatic mistake. Having the aliens show up and stomp the living daylights out of us before we’re even aware of what’s happening (imagine the Sixth Fleet vs. Renaissance Florence only worse) doesn’t make a very good story, and consequently very few people decide to write that story. This would be fine except that everyone has absorbed these stories as the way it’s most likely to happen, and so when they imagine contact with some kind of extraterrestrial it’s science fiction aliens with better, but not ridiculously better technology (and ideally an Achilles’ Heel.) This thinking is the most obvious distortion, but as I have argued in other posts, I believe it distorts even the thinking of those scientists and academics who are paid to think deeply about this problem. In any case the key thing I want you to take away from the “Mistake of Dramatic Timing” is that IF aliens were going to show up, or more technically if aliens are ever going to be aware of us, than it’s almost certain that it’s already happened, that nothing dramatic will happen in the next few hundred years.
We have to deal with one final argument before we move on. The point I’m making is that nothing has changed in the last few hundred years as far as what aliens might be out there and what they might want from us. However, to be fair, some things have changed recently in terms our ability to detect potential aliens. And it is possible that this is a place where something might change soon. But with every year that passes this becomes less and less likely. Also as I have argued before, if aliens are out there and they want to be detected they could almost certainly figure out how to make that happen. Much harder is not being detected, and that task is much easier if you’re aware of what’s trying to detect you, which takes us back to where we were. Either aliens are aware of us now, or very probably they never will be.
As I said I enjoyed the Bobiverse, (I even enjoyed Independence Day, probably because I was less jaded back then) and they are fiction, so I entirely forgive them for getting this wrong. But fiction is not the only place where people are proposing solutions to the paradox. There are academic papers doing the same thing, and recently one was released which claimed to dissolve the paradox. Obviously this is the sort of thing that needs to be taken more seriously.
The paper doesn’t actually center on the paradox. It takes as its focus Drake’s Equation, which will hopefully be familiar to readers of this blog. If not, basically Drake’s Equation attempts to come up with a guess for how many communicating extraterrestrial civilizations there might be by determining how many planets might get through all the hoops required to get to that point (for example all planets, multiplied by the percentage with life, multiplied by the percentage of that life that’s intelligent, etc.). And it turns out that if you multiply the average of all the terms in the equation, that you get an expected average of quite a few communicating civilizations, and yet there aren’t any, which then brings in the paradox.
The authors of the paper point out that if the distribution of the estimates is narrow, and if it looks like a bell curve, multiplying the averages would give you a pretty good idea of what the overall probabilities are. You could say something like, “We think with 68% certainty, that the number of communicating civilizations in our galaxy is between 1 and 11. With an average of 6.” Which would imply that there probably is a paradox. But if the distributions are ridiculously wide (they are) and on top of that not normally distributed (and apparently they’re not that either) then you can end up in a situation where the most probable situation is that we’re alone, even though the average number of expected civilizations is greater than one.
If we are alone, that means that there’s something which keeps other civilizations from getting to the point where they can communicate. This has come to be called the Great Filter, and what this paper and other’s claim is that, “Good News!” the filter is most likely behind us. I don’t have the time to digest all the math in the original paper, but I’m inclined to take it’s conclusions with a large grain of salt, for a few reasons:
Reason 1- As uncertainty decreases it almost always points to life being more common
The authors point out that there’s a large degree of uncertainty for all of the terms in Drake’s Equation, fair enough. But one assumes that as time goes on and our knowledge increases that uncertainty will get less. One great example of this are the exoplanets that have been discovered by the Kepler Space Telescope. This has vastly reduced the uncertainty in the number of stars with planets. (Which is the second term in the equation.) The question is, as uncertainty is reduced, in which direction will things head? Towards a higher estimate of communicating civilizations or towards a lower estimate? The answer, so far as I can tell, is that everytime our uncertainty gets less it updates the estimate in favor of communicating civilizations being more common. Let’s look at three quick examples of this:
- There’s the one I just mentioned. According to Wikipedia when Frank Drake first proposed his equation, his guess for the fraction of stars with planets was ½. After looking at the data from Kepler, our current estimate is basically that all stars have planets. Our uncertainty decreased and it moved in the direction of extraterrestrial life and civilizations being more probable.
- I also talked about number of rocky planets, which relates to the term in the equation for fraction of total planets which could sustain life. As I mentioned above we used to think that rocky planets would only appear seven billion years or so into the lifetime of the universe. Now we know that they appeared much earlier. Once again our uncertainty decreased, and it went down in the direction of life and civilizations being more probable.
- Finally there’s the existence of extremophiles. We used to think that there was a fairly narrow band of conditions where life could exist, and then we found life in underwater thermal vents, in areas of extreme cold and dryness, in environments of high salinity, high acidity, high pressure, etc. etc. Yet another case where as we learned more, life became more probable, not less.
The trend is clear and I think it will continue.
Reason 2- The wildcard of panspermia
The next area where I have reason to doubt that the paradox has been “dissolved” is the idea of panspermia. And from where I sit, it appears that the evidence for that is increasing as well. On the off chance that you’re unfamiliar with the term, panspermia is the idea that life, in its most basic form, started somewhere else and then arrived on Earth once things were already going. Of greater importance for us is the idea that if it could travel to Earth there’s a good chance it could travel anywhere (and everywhere). In fairness, there is some chance life started on say, Mars and travelled here, in which case maybe life isn’t “everywhere”. But if panspermia happened and it didn’t come from somewhere nearby, then that changes a lot.
Further, it’s important to remember that panspermia is not accounted for in Drake’s Equation, and that makes it a wildcard for this entire question. Given the tenacity of life I’ve already mentioned above, once it gets started, there’s good reason to believe that it would just keep going. This section is more speculative than the last section, but my gut says that panspermia is probably more likely than people think. That said, I’ll lay out my reasons and you can decide for yourself.
- Certain things double every so many years. The most famous example of this phenomenon is Moore’s Law, which says that the number of transistors on an integrated circuit doubles every two years. A while back some scientists wanted to see if biological complexity followed the same pattern. It did, doubling every 376 million years. With forms of life at the various epochs fitting neatly onto the graph. The really surprising thing was that if you extrapolate back to zero biological complexity you end up at a point ten billion years ago. Well before the Earth was even around (or Mars for that matter). Leaving Panspermia as the only option. Now the authors confess this is more of a “thought exercise” than hard science, but that puts it in exactly the same category as the paper which “dissolves the Fermi Paradox”. (I would actually argue that the Moore’s Law analogy is probably less speculative.)
- There’s a significant amount of material travelling between planets and even between star systems. I mentioned this in a previous post, but to remind you. Some scientists decided to run the numbers, on the impact 65 million ago that wiped out the dinosaurs. And they discovered that a significant amount of the material ejected would have ended elsewhere in the Solar System and even elsewhere in the galaxy. Their simulation showed that around 100 million rocks would have made it to Europa (a promising candidate for life) and that around a 1000 rocks would have made it to a potentially habitable planet in a nearby star system (Gliese 581). Now none of this is to say that any life would have survived on those rocks, rather the point that jumps out to me is how much material is being exchanged across those distances.
- Finally, and I put this last because it might seem striking only to me. I came across an article recently that said the very first animal had 55% of the DNA that humans have. They ascribe this to an “evolutionary burst of new genes”, but for me that looks an awful lot like support of the first point in this list. The idea that life has been churning along for a lot longer than we think, if the first animal had 55% of our DNA already half a billion years ago.
Now, of course, even if panspermia is happening, that doesn’t necessarily make the dissolving-the-paradox guys wrong. You could have a situation where the filter is not life getting started in the first place, the filter is between any life and intelligent life. It could be that some kind of basic life is very common, but intelligence never evolves. Though before I move on to the next subject, in my opinion that doesn’t seem likely. You can imagine that if life itself has a hard time getting started, in any form, that out of the handful of planets with life, that only one develops intelligence. But if panspermia is happening, and you basically have life on every planet in the habitable zone, a number estimated at between 10 and 40 billion, then the idea that out of those billions of instances of life that somehow intelligence only arose this one time seems a lot less believable. (And yes I know about things like the difficulty of the prokaryote-eukaryote transition.)
Reason 3- To little accounting for the data we do have i.e. Earth
The final reason I have for being skeptical of the conclusion of the dissolving-the-paradox paper is that as far as I can tell they give zero weight to the fact that we do have one example of a planet with intelligent life, and capable of interstellar communication: Earth. In fact if I’m reading things correctly they appear to give pretty low probability to even the Earth existing. My sense is that when it comes to Fermi’s paradox this is the one piece of evidence that no one is quite sure what to do with. On the one hand, the history of science has been inextricably linked to the mediocrity (or Copernican) principle. The idea that Earth and humanity are not unique, we’re not the center of the universe or of the solar system or what have you. Humans are not special, we’re just another monkey, etc. And yet on this one point we are currently unique. We are the only example of intelligent life for which we have any evidence.
You might think there is no, “On the other hand”, but there is. It’s called the anthropic principle. And let’s just say I’m not a huge fan. This is not the first time I’ve talked about the anthropic principle and I would point you at one of my previous posts for a more detailed criticism, but basically it says that conscious life will only be found in places where conditions allow it to exist, therefore when we look around and find that things are set up in just the right way for us to exist, it couldn’t be any other way because if they weren’t set up in just the right way no one would be around to do the looking.
As I said, I’m not a fan. I think it’s a cop out. And in order for us to be as unique as this would imply, there would have to be something entirely unique about Earth, or a series of very improbable things that combined to create an entirely unique Earth. And so far while there’s a lot of speculation, there is no smoking gun. And, again, remember, every other time we thought we were unique, we ended up being wrong. It’s my firm belief that this time isn’t any different.
In case you’ve missed my central point, which is entirely possible, since I’m not sure I actually mentioned it, and it’s more of the central point that runs through all of my posts about Fermi’s Paradox. The point is, there’s numerous, very good reasons to think that there should be other intelligent species out there, despite people claiming to dissolve the paradox. And if there are aliens out there then there should be some evidence of it. This is unlikely to change in the next 100 years. We either already have the evidence or we never will. Based on all of this, the simplest explanation which fits everything we do know, is that we do have evidence of something beyond this earth, and we have labeled it God.
Life isn’t the only thing that can get spread really far in tiny amounts. Money can do that as well. Perhaps if instead of asking for donations, I should ask for money panspermia. That makes it sound awesome!