In this episode of Brokernomics, I'm joined by Grant Donahue to talk about the Drake Equation and the Fermi Paradox, and why we might not be the only ones out there looking for alien life.
00:17:24.260But the more useful thing about that is,
00:17:26.820is the standard candle tells us that there isn't anything strange going on with those signals that could be confusing us.
00:17:32.460It's telling us that the metallosity in those galaxies is similar to us.
00:17:35.980It's telling us that the stars are of similar composition.
00:17:38.480So we're essentially saying we can't posit that perhaps the galaxies we're looking at are red shifted to the degree that we wouldn't recognize it,
00:17:46.820because the standard candle is telling us, no, our light readings here are consistent,
00:17:50.060or at least it's giving us a reading that we can use to provide an adjustment.
00:18:23.640So we go through the Drake equation in a moment, and we can pare down each of those terms within it to get down to basically one advanced civilisation per galaxy, as in...
00:19:24.780Because one thing that the Drake equation doesn't do a great job of is accounting for time.
00:19:28.540This is why the firstborn hypothesis came considerably later.
00:19:31.260Because the Drake equation did not account for the amount of time it takes for a planet to develop to the point where life could exist on it.
00:19:38.520And so you can eliminate a huge number of stars.
00:20:20.140Again, it's not to say anything against its author, but it's simply...
00:20:24.380It was proposed long enough ago that when you start adding terms and you make certain assumptions,
00:20:28.220you actually can get down to numbers where it's...
00:20:31.540I'm not going to say certain, but it's not a completely mind-boggling possibility that you might not expect to get more than one civilization in the sort of radius where we could reliably detect them.
00:20:55.480For example, one of those is you're assuming that the only viable kind of life is carbon-based life.
00:21:02.100Now, that was an assumption he made where you could actually be more generous because you could say, well, there are actually more candidates.
00:21:08.180There's silicon and there is silicon, sort of...
00:21:13.820And there are some possibilities for perhaps sulfur.
00:21:16.820And if you allow for those, then suddenly you can be a lot more...
00:21:27.440The reason why carbon-based life is so specific is because most reactions that we can tell that require carbon-based life need to take care...
00:21:34.820Need to take place in a liquid medium.
00:21:36.440And almost the only liquid medium suitable for those is water.
00:21:39.580So there's a very specific temperature range.
00:23:09.700Now, the number of them that have stable planetary systems is a different matter.
00:23:12.920But at least, as far as we can tell, the best way I can put this is every time we've gotten better at detecting planets, we've found a greater and greater proportions of exoplanets around stars.
00:23:24.260So that's the sort of trend that leads to the point where you start thinking, well, are there any without them?
00:23:28.440And we have a few that are pretty strong candidates.
00:23:31.520Proxima Centauri has no detected planets.
00:23:41.220We've got the number of planets per solar system with an environment suitable for life.
00:23:45.340So this is the point that you were just making, because this assumes it's going to be carbon-based life.
00:23:50.380And therefore, it's going to be only basically planets within the orbit of something like Venus to Mars.
00:23:55.860So there are, in our system, there are going to be three planets that qualify for N.
00:24:00.600So if that's true, if our solar system is anything to go on, that's a reasonably high proportion.
00:24:06.500But even if we plug in a lower number here, say 0.5, as I did for my equation when I ran this, 0.5 is a lot less than the three that we've got here.
00:24:15.040So you'd have to assume that our system is rather bountiful when it comes to habitory planets.
00:24:55.760You actually have to be in a point where, even at the highest point of luminosity and the lowest point of luminosity, the star won't scorch or freeze the planet such to the point that it's irreversible.
00:26:37.720We of the the way I always try to think about it is that if you look at the entire history of life on Earth, something like five sixths of it is just multi is just single cellular life without nuclei.
00:26:52.440And then there's the Cambrian explosion.
00:26:54.300And then after that, it's not fair that the pre-Cambrian, the early the late pre-Cambrian does have some multicellular life.
00:27:00.320But for the most part, for the vast majority of the Earth's history, despite the fact that the conditions were nominally there, multicellular life just didn't develop.
00:27:08.080OK, so we had what viruses and bacteria and that's about it, was it?
00:27:11.280We're actually not even sure viruses, but we can't tell how viruses evolved.
00:27:15.900We were not entirely sure if they evolved from non-living material or if they're bacteria that lost their own metabolisms.
00:27:40.880Archaea is, so there are the categories of life, animalia, plants, fungi, and bacteria, and archaea.
00:27:54.200And archaea are, this entire family, they're as varied as the category of animal or as of plants.
00:27:58.600And they are universally singular cellular.
00:28:01.340And as far as we can tell, none of them are ever pathogenic.
00:28:03.580So despite the fact that they are as common as bacteria and as common as other forms of single cell life, and they're everywhere, we have never found a single one that is pathogenic, that causes disease.
00:28:14.580It is so alien that it doesn't seem to interact with us at all.
00:28:16.960So I'm going to bank that thought for when we come on to the Fermi Paradox later, because that gives me something there.
00:28:26.240And actually, the other thing on the point of life emerging is, I don't know if you heard it, but there is this one guy, I wish I remembered his name, who basically put forward the notion that life is a natural consequence of the laws of thermodynamics.
00:28:40.000Because when you've got energy bombarding a system, that energy has to go somewhere.
00:28:46.040And I'm butchering his argument, but it's something like the path of least resistance is for that energy to be fed into basically creating life.
00:28:55.180Because it's a way of dissipating the energy.
00:28:57.740It's it's if you provide energy to a system or if you provide energy to a system, it will tend to arrange itself into ordered into an ordered into into an ordered state.
00:29:09.220Crystals tend to grow in the presence of energy, that sort of thing.
00:29:12.460And so life could be one means of expressing it.
00:29:15.360Admittedly, that's a teleological argument in that it's an argument from consequences.
00:29:19.600But but I think there is something to that.
00:29:22.880But but it's not it, but it's but you don't fundamentally dispute that it's impossible, that life is more or less an extension of the laws of thermodynamics.
00:29:31.260And therefore, we can assume that almost anywhere where you bombard a suitable planet with enough energy, life is going to emerge because it kind of has to because the energy needs to go somewhere.
00:29:42.820I'm not sure I would say that I inherently agree with it, but I'm not going to say that I I'm good.
00:29:48.220I can't dispute it, but I would need to because I can think of some counterexamples.
00:29:52.900Admittedly, they're somewhat trivial counterexamples, but I can think of some reasons why I would disagree, because life, unlike certain other kinds of energy investments, is not arbitrarily investable.
00:30:03.600You can't pour an arbitrary amount of energy into life into a system and get more and more life out of it.
00:30:08.140Eventually, the amount of life actually starts to decrease because the system is too energetic for chemistry to take place.
00:30:12.480And so the amount of energy being supplied is actually it's not an unconstrained value past a certain point.
00:30:21.680But I think there is something to that, that if you're providing a suitable amount of energy for a long enough period of time to a chemically active system, you would expect very complex things to start emerging.
00:30:31.220And life seems one of the very natural courses of it.
00:30:34.360That's interesting. When you say one of the things, are you able to envisage something other than life, which is the product of increased complication?
00:30:47.600Plate tectonics. Plate tectonics is a great example of that in that you have you've supplied you have an energy being you have energy.
00:30:54.260You look at the simplest plate tectonics, a stagnant lid, where you just have the inner core.
00:30:59.100You have an inner core, which is liquid. And then outside of that, you have a solid core, a mantle and a singular shell that like Mars.
00:31:06.140But then as you have something more massive like the Earth, we have an inner core, which is solid, an outer core, which is liquid, a mantle, which is sort of an amorphous liquid or an amorphous solid.
00:31:18.960And then you have a crust and those crustal plates are broken up into different pieces and they're moving across each other and exhibiting different failure methods and all that.
00:31:26.820Plate tectonics, I think, is a really good example. And just the hydrosphere in general is a great example of how pouring energy into a system can produce an enormous amount of complexity.
00:31:36.260And unlike life, it doesn't seem to be strongly constrained until you melt the lid.
00:31:39.600And even then, you know, like almost all of our diamonds come from exactly that, where the mantle was hot enough to burn through the plate and create kimberlite pipes, which then form the diamonds.
00:31:50.420But these things are not mutually exclusive, as we've done with here.
00:31:53.820They can they can develop alongside each other because there was a lot of energy being poured into the system.
00:31:58.660Indeed. And they can also drive each other. They can further enhance each other.
00:32:29.600Yes. What do you what do you think about that one?
00:32:33.840I mean, I don't see what needs to be the case, but it's for me, it doesn't seem to solve anything because the life has to start somewhere in that, you know, you you it's a bit like and I'm a Catholic, but nothing annoys me more than bad arguments for God.
00:32:48.700Because it's the only thing that annoys you more than bad arguments for the other side is bad arguments for your own side, which is you say, well, the universe needs a universe creator because it exists.
00:32:57.480And then you say, well, then God exists.
00:33:03.600Well, panspermia is is is is is is an option, but it still ultimately puts you at a point where, well, then where do the bloody life originate?
00:33:12.420All that it serves to do is to call into question whether Earth is actually suitable for a candidate for life to arise or if it isn't.
00:33:18.540And if you're only adding questions without actually adding any answers, it's not super useful tool of explanation.
00:33:39.360If it if it is landing on a planet where it's suitable, you kind of assume that it would emerge on that planet anyway, on the grounds that it is as we've established suitable.
00:33:58.180So we've agreed that life emerging is actually fairly straightforward and simple.
00:34:03.400And the Drake equation kind of skips your complex life term and goes straight into intelligent life.
00:34:10.980So we're going to have to roll complex life and intelligent life into there.
00:34:14.260Just addressing the point of of intelligent life emerging.
00:34:17.560Again, on the planet that we've that we're on, you know, you can make an argument that has happened.
00:34:22.980Once, but maybe three times on our planet, if you include whales and dolphins, I don't know whether that whether they would necessarily count as intelligent or possibly they also mean technologically using, you know, tool using or something like that.
00:34:37.940But then dolphins do use tools to a limited extent.
00:34:45.200Intelligent life emerging, but we might have to roll in your complex life factor into it as well.
00:34:49.500So this is actually one of my favorite examples of how you can sort of decompose problems like this to make them more salient.
00:34:56.200If you would like to see the full version of this premium video, please head over to lotuseaters.com and subscribe to gain full access to all of our premium content.