Science & Technology Q&A for Kids (and others) [Part 121]

Right. Hello, everyone. Welcome to another episode of Science and Technology. Q and A for kids and others. I thought maybe this time I would try and emphasize questions about a particular topic. And I thought the topic we'd pick is the future. But I see there are a bunch of other interesting questions that have already come in, and maybe I could try and address some of those. First, he says, hopefully there's a question from Leo. Could every exoplanet have a habitable zone? If you can get just far enough away from the star? What makes a planet habitable? Well, okay, so when we talk about habitable, we probably mean to life as we know it here on Earth. And we certainly don't know what the kind of general version of what life is like anywhere might be. I think the thing that is characteristic of life, as opposed to other kinds of systems is life is sort of doing what seems to us like kind of meaningful molecular scale computation. It's moving all those molecules around in ways that sort of, in some sense makes sense to us. But it's kind of a circular thing because we are examples of that life too. And so the fact that those things that sort of make sense to us, but we are an example of that kind of life, it's not clear that's a, a general way to define things. And the one thing we can say for sure is, is there are sort of complicated things going on in living systems. But there are plenty of complicated things going on in other systems, whether it's turbulent fluids or geology or wherever else that we don't usually think of as being systems that are alive. And when it comes to life on Earth, there's a lot of, kind of historical connection between all different examples of life on Earth. All life on Earth has just one idea about how to be constructed out of proteins, specified ultimately by RNA at least. And so all life on Earth, even though there may be many different kinds of sort of molecular computation that could be done, all specific life on Earth is based on very particular molecules like RNA that make it work. And once you have those particular molecules, you're pretty constrained in things like the environment, the kinds of, you know, do you have water, do you have liquid water, do you have temperatures in a certain range? Those kinds of things. We know that there is some extreme life on Earth, so called extremophiles, for example, that live in hydrothermal vents full of sulfur and things like that in the deep ocean. We don't know, for example, how deep life goes under the surface of the Earth, for example. We don't Know, we pretty much know there's no life in the upper atmosphere. So there's a certain range in which life, with its chemical composition as we have it here on Earth, can exist and also a certain environment with things like water that are used there. So the question would be, if you've got some random exoplanet around some other star, does it have on it at least a region that is habitable in that sense, that has the appropriate range of temperatures and chemical compositions and so on to support life of the kind we know on Earth? And there are different forms in which that could occur. I mean, for example, on Earth we have life existing in things like our oceans, in things like the atmosphere and so on. But one could imagine other planets, for example, where there's, you know, a layer of ice and there's an ocean underneath the ice. Enceladus, I guess a moon of Saturn, has the potential to have sort of an under the ice ocean, so to speak, which could be, for example, warmed by. I think in that particular case, probably not. But in general, such things could be warmed by radioactive decay and things like that in the inner planetary object. So even sort of knowing, oh, there's a planet in this position and it has this material visible in its atmosphere or on its surface, even that isn't enough to tell one, oh, there can't be anything sort of in the right range that exists in sort of an ocean underneath the layer of ice or caverns deep inside the planet or some such other thing. So hard to know that. But in terms of kind of an environment that's a bit like what we have on Earth, there's a certain given a star of a certain size. So stars typically go through this evolutionary sequence. Most stars go through the so called main sequence of stages. Our sun is a G type star that's sort of more or less in the middle of the main sequence. And a star of a given mass will go through that particular sequence of evolutionary steps. So for example, very big stars will often go through their evolution in just a few million years, as opposed to something like the sun, which has like a 10 billion lifespan. And at different times in the history of the star, the star will produce different amounts of heat and light and other and sort of amounts of energy. It will be generating different amounts of energy and radiating them out. And so a planet would have to be a different distance away to sort of have the same total amount of heat, for example, reaching it as the Earth does from the Sun. But for most, I think it's probably true Is it right? I would think so. That for any size of star that will be a star and things you can get stars maybe down to, I don't know, perhaps a tenth the size of the sun, maybe a little bit smaller. I'm not sure. But by the time the thing gets too small, it won't have the sort of gravitational effect necessary to actually sort of push its constituents together to start nuclear fusion and to make it actually act like a star. It'll just be something, just a cold blob, like a big planet instead. So I think it's true that for all things that will make stars, there is a distance away from the star that a planet could be orbiting at which it will have the same amount of radiation of heat, for example, from the star that the Earth has from the Sun. So that's one thing. So another thing is that there is certainly an effect. The Earth's axis is tilted 23 degrees relative to the plane on which it orbits the Sun. And that's what causes us to have seasons and so on. There are places on the Earth where sort of the surface of the Earth at a particular season is tilted in such a way that it's getting sort of the full heat from the Sun. And at another season, that place on the surface of the Earth is kind of at a diagonal away from the Sun. And so the. The amount of heat falling on it per. In each unit area of that surface is smaller. And so it will be colder then. So you can decrease the amount of heat reaching you from the star by kind of being at an angle, by being sort of at the sort of. For example, if you're at the top and bottom of the planet, so to speak, relative to the star, then the amount of heat reaching you per area on the surface will be lower because there are all these sort of rays coming from the star. And those rays, each of those rays kind of has to cover a larger area as it sort of grazes across the top of the planet, so to speak. And that means that the amount of heat per unit area, which will determine how hot the surface gets, will be smaller. So you can kind of reduce the amount of energy getting to your planet by being on a part of your planet that is kind of less exposed to the star. Now, obviously, you can do even more than that. If the planet is. If the planet is rotating, like every day it's turning around and its different sides are each being exposed to the star. Well, then at least every day you'll have heating from the star cooling. When it's away from the star and so on. But some planets, particularly ones close to a star, will get locked in place. Like this happens with Mercury, for example. It happens with the moon relative to the Earth, so that only one face of the planet is facing the star at any given time. And the back face of the planet will not get heat directly from the star. And so you'll get this big difference in temperature between the front of the planet, so to speak, facing the star, and the back of the planet not facing the star. And that means, for example, you might have in the Terminator in the kind of the dusk zone right between where it's kind of continuously day because it's always facing the star, and continuously night, but it's always away from the star in that sort of dusk zone, you might have some reasonable temperatures, by the way. That's why, for example, when Apollo 11 landed on the moon, it landed right around that Terminator. And that's why when you look at pictures of the astronauts from Apollo 11, they have these really long shadows on the ground because it was just dusk for them. And that was done in order to avoid them being too hot or too cold. And so similarly, you can expect to have such a zone for a planet which has been sort of locked in place, to have always one face to the Sun. You can expect that kind of thing. So I think the conclusion would be that in any given sort of solar system around another star, there will be a distance away from the sun, from that star that will lead to planets that have sort of reasonable temperatures relative to what they are on Earth. Now. Will they also have things like water? Well, there's a certain amount of universality to the kinds of chemical compositions that exist, at least so far as we can tell, in planets of different sizes. But it's not exactly the same. I mean, Venus has a very different environment from Earth, even though it's more or less the same size as Earth. Mars, likewise, some of those things may be that Mars used to have an environment more like the Earth, but it all sort of got away over the last 5 billion years or whatever. And so there are things like that that happen. But that would be my thoughts there. Let's see, there was a question here from William. Why do we measure sound using decibels? Well, actually, different ways to measure sound. But the question is, how loud is that sound? Well, the. The usual. So. So sound. What is sound? Sound is ultimately vibrations in the air. It's a sequence of compression of the air, expansion of the air, compression of the air, expansion of the air. So the loudness of a sound is at some level the amount of compression and the amount of rarefaction that exists in the sound wave that is the sound, so to speak. And the variations of density of air, for example, from squashing the molecules together when it's compressed and pulling them apart where it's rarefied, so to speak. Those, those variations in the density, the number of molecules that are there, are pretty small. But the amount of those variations determines the loudness of the sound. When that sound wave hits the your eardrum, it's going to be the case that there are either a bunch of molecules that are going at the moment where the sound is, the sequence of. Of it's a. It's a wave where it has a. It's where traveling at the speed of sound, There is a lump of compression, a lump of rarefaction, a lump of compression, and so on and so on and so on. And when that lump of compression, for example, hits your eardrum, that's the thing that pushes on the little bones. That eventually pushes on the hair cells inside cochlea and eventually makes your ear, you sort of record, oh yes, I heard a sound. Okay, so eventually one's measuring the amount of pressure difference associated with the sound. But there's a feature of human perception which is that when you double the pressure difference, you only it's not that you hear that sound as twice as loud. In a sense, your effect, that sound just seems to be progressively louder, like linearly louder. Even though the pressure might be increasing by factors of two or whatever else. And so the measurement of sound intensity is usually given in decibels. And it's a mechanism that reflects the way that we humans perceive things like sound, that we perceive it on a logarithmic scale. When the sound is twice as loud, we only perceive it as sort of a certain increment louder. And then when it's, let's say, four times as loud, we perceive it as sort of linearly louder than the sound that was half the pressure difference. So decibels are kind of set up to be this logarithmic scale that records that says move one unit. When the sound gets twice as loud, let's say it's a way that's pretty common. Many features of human perception have this feature that even when there's twice the sort of physical intensity, we only perceive it as sort of linearly more. We perceive it as progressively more, sort of a linear amount of effect. The same is true with touch and other senses as well. So that's kind of why sound gets measured on this logarithmic scale, is because that's how we perceive it. Now, you can ask, why do we perceive it that way? And that's an interesting question that has to do with how nerves work and things like that. And I'm not sure I can completely explain why it is that. Let me think about this for a second. Why our perception is on this kind of logarithmic scale. Not sure that I can really explain that. And I'm not even sure that we really understand why. Why it works that way. I could make some guesses. Let me think. Yeah, I'm not quite sure. There's a variety of sort of laws in experimental psychology that have been known since the 1800s that have this property that they have this kind of logarithmic character to them. But why they're true, I'm not sure. It's a feature of our. Our sort of perception by our brains and by our sensory organs and so on. Now, when it comes to sound, there's all kinds of trickiness because there are, in addition to decibels, which are the most common measure of sound, where, you know, I don't remember, speech is perhaps 20 decibels, 30 decibels, something like that. And by the time you've got, you know, the rocket launch, it's 100 decibels. And it doesn't seem like that's that much difference. But that sort of linear difference in decibels is a large factor of difference in actual pressure. And that's just how that scale works. There are other scales. There are things called fons, which are another scale of kind of sound intensity. And one of the tricky things is that the frequency of the sound also affects how loud you will perceive it. So, for example, one of the features is if you increase the frequency. Oh, gosh, how does this go? I think that the. Just the. I think it goes like the square of the frequency, if I remember correctly, is the immediately perceived kind of sound intensity. And so there's a question of whether you correct that for that, whether you correct for the perception of sound as a function of frequency. Now, your typical person can only hear up to a certain frequency. So, for example, maybe 15, 20 kilohertz, 15 or 20,000 vibrations per second is kind of. And as one gets older, the frequency to which one can hear goes down. Typically the. I'm happy to say mine hasn't gone down too much yet. Touch wood. So if you play a sound at, let's say, 50 kilohertz, no human will hear that sound. Some animals with really small ears might hear that sound. I'm not sure if dogs can get up that high, but dogs can hear beyond the human range. I'm not sure exactly to what frequency, but in any case. So in terms of decibels, you could have a very intense sound that had a big pressure difference at 50 kilohertz but no human would actually hear that sound. And so this other scale, fons are more of a true perception of the sound by people and that corrects for that effect and tells one sort of how loud it will seem to a person, so to speak. So anyway, that's a bit of a story of how sound intensity is typically measured. Well, let's see. See a question from Aaron here about what advances in synthetic biology do you think will happen in the short term, Long term, very long term. And a question about visiting Inco Bioworks in Boston, which I have not done. Maybe I should. I've run into maybe the founder somewhere, but I haven't been doing lab visits for a while. I usually find it interesting to visit certain kinds of labs, I have to say biology labs sometimes that are working on molecular scale things, sometimes have a certain kitchen look to them, so to speak. It's just a bunch of things that look like kitchen appliances and sort of the most interesting stuff will be things like the liquid handling robots, if they have those. Otherwise it'll just be, oh, you take this set of, well, not quite test tubes these days, but 96, well, plates or something and you move it from one, one machine to another and each machine is kind of this white thing with a, maybe with a control panel that looks like a typical sort of modern kitchen appliance. And it's not the most exciting kind of visual thing to see. I mean something like an optics lab. You'll typically see, you know, all that. There'll be an optical table and all those lenses will be out on the table and you can kind of see them because after all they're supposed to operate by having light go through one lens to another. And so it tends to be a little bit more, more kind of tourist friendly than your average biology lab. But in any case, synthetic biology. So first, what is synthetic biology? Well, all of the critters of the earth, their characteristics are specified by their genetic material, usually DNA, occasionally for viruses, just RNA, but DNA for us humans. There are 6 billion of these base pairs, these sort of different units of collections of atoms that are all stuck together on this backbone. And the thing that specifies how the molecules that make us up, the proteins that make us up what those proteins should be, they're specified by these sequences of so called base pairs. Each base is this clump of atoms that's on the backbone of the DNA molecule. So in the case of us humans, we've had, I don't know, 3 billion years or something of evolution. And we've got, I don't know what it is, you know, 40,000 genes, 40,000 different regions of our DNA that specify proteins that we should make that form the proteins for our skin or our eyes or our brain or whatever else. And that collection of that genetic sequence, that collection of proteins have been determined by biological evolution. And in a sense that process is there's some random change in a protein and then you make a whole organism, and then the organism is either more successful or less successful. If it's more successful, then they'll probably have more children, so to speak. And that means that that particular genetic sequence which will be passed with some probability to the, of that organism will tend to become more prevalent, more common. And the organisms that didn't have that change in their genetic sequence will become less common. And so gradually that genetic sequence will start to exist in more and more organisms and it'll become part of the kind of the thing that gets passed to the future, so to speak. So the idea of synthetic biology is let's not just use these processes of evolution to determine what the genome should look like. Let's just make the genome by engineering, let's specify the genome, let's have sort of a computer aided design system, and let's sort of draw out the genome and say what it should do. Now it's possible to do various kinds of, Sort of various versions of this. You could take a gene from, from one organism and stick it in another organism. Very common case of that is there's jellyfish that glow in the dark and they're, what is it? GFP Genes are very popular as ways to do biology experiments because you transport that gene to another organism and when that gene is, and you put that gene into the genome of another organism, and when that gene gets used, it'll produce jellyfish protein. And so even in your mouse or something like this, there'll be some pieces of the mouse that become glow in the dark because there's been jellyfish protein produced there that glows in the dark. And there are a whole variety of different places in animals and plants and so on. Where at least, well, in some cases, for practical uses, for some cases, for Experiments, one has done that kind of modification. I mean, there are more elaborate things one can do when the organism is sort of alive and well. You can have a retrovirus which can go and sort of reattach that can go and kind of put that sequence into, into the organism. Or in modern times, one can do actual gene editing using this CRISPR cas. Well, a variety of versions of this. Now a thing where essentially you have something that was kind of taken from a, I guess from a bacteriophage, from a, from a virus that operates on bacteria. Originally that was sort of where the idea came from, but in the end now it becomes just these molecules that can attach themselves to DNA and splice in different, different pieces of genetic material, but just making sort of small edits to, to a genome that already exists. But the thing one could imagine doing is, well, let's just make a genome from scratch. People have been interested in sort of what's the minimal genome that will make an organism that can reproduce itself and things like that. I'm not sure what the smallest is right now. It's still pretty big, I think. But you can ask the question, could we just make life forms from scratch? Biological evolution has done a pretty good job inventing a bunch of mechanisms that are used in life. And it's not completely clear that we can do better in the near term, at least with our engineering, but we can sort of imagine kinds of things where we could just sort of say, I want an organism that does this or that, so get me a genome that will produce that organism. It's a little bit like saying, I want a computer program that does this or that. What kind of code should be in the program to make the program do this or that? However, it's trickier than that because the distance between the underlying specification of that sequence of base pairs on the genome and what the actual molecules do is a much longer distance than what we typically have in computer code that we would write using a kind of computational language that we, or programming language that we would normally use. And in particular, for example, just given the sequence of base pairs, it's even hard to predict what shape the molecule that will be made by making a protein from the units that come from that sequence of base pairs, what shape that molecule will be. This is the problem of protein folding, which at this point, there is reasonable machine learning capability to know what shape of protein you'll get. Now, as one piece of the story of designer things in biology, one can ask, well, let me just make a protein that's a certain shape. Let me make a protein that will attach to this particular system in, that exists in some other biological organism. Let me make a protein that will be useful for essentially making some technological device, whatever else. It's been pretty hard to do that, but it's getting a little bit easier. And I think even in recent times, just as people talk about having or have systems where you can give a piece of text, say, you know, make a picture of a, a crocodile dancing on the moon or something, and that picture will be synthesized by a generative AI system by essentially taking pieces from things that the generative AI system has seen on the web that had textual tags that were similar to what one's asking for now. So there'll be some sort of collection of crocodile like picture elements and some collection of sort of things you do to a picture to make it look like dancing and so on. And this is something that in kind of a Neural networks succeed in kind of extracting the essence of what are in many millions, billions of pictures and sort of reassembling them in such a way that they can follow some textual prompt that you give. And so the idea is to do the same kind of thing for proteins. You say, I want a protein that is in the shape of a corkscrew, et cetera, et cetera, et cetera. Well, so long as there's been, if you can kind of find existing sort of fragments of protein that sort of contribute to pieces like that that are known from the proteins whose structure has actually been analyzed. And then you can make use of the fact that one knows from the underlying kind of sequence for the protein what shape it will take on. One has sort of at least a fighting chance of being able to go from sort of almost a textual description to a natural shape of protein. And that's kind of a way that one can imagine building sort of at a molecular scale, things that have particular shapes. Now, you know, what shapes do you need? Well, you need to invent some kind of engineering structure that can operate at a molecular level and where these sort of puzzle pieces will fit together to achieve the thing you want to. I think that as one sort of the big challenge is to make things that operate at a molecular scale and are useful from the point of view of things we want to achieve and what would be useful to us. Well, having a computer that was made at the level of individual molecules that will be useful. And what our computers right now are, their features are pretty small in the billionth of a meter type range. But computers tend to have a couple of characteristics. When you look at their CPU chips, they tend to be very two dimensional. They tend to just have sort of wires going in a, in a kind of a grid that looks like it might be, you know, a cityscape from the surface of the earth. They don't tend to be big three dimensional structures where they're sort of wires going up and down and so on, as well as sort of just flat on a surface. Similarly, what microprocessors do is they have wires that effectively transport electricity. In biology, there are lots of things that transport, not just electrons that make electricity, but, I don't know, protons, various kinds of other atoms, small molecules, things like that. It's kind of a, a system of tubes, so to speak, that aren't just tubes that are like wires where electrons can go through them. They're more like other kinds of things that can transport other kinds of microscopic objects. And so that's another thing that one can imagine making sort of at a molecular scale that is a little bit more biological in character. At least biology is the one example where we've seen that work. But so as soon as you're transporting around, you know, different atoms and things like that, you can imagine making something which will be sort of an assembler that just takes, oh, I've got a sodium atom here and a carbon atom here, an oxygen one here. And I'm going to have these tubes, deliver them all to the right place. And pretty soon I'm going to make, you know, something that is kind of like, I don't know, a piece of Styrofoam or something, in other words, that you'll be able to, just by having this kind of molecular scale machine, be able to just move atoms around so that you can assemble any material you want where you're assembling it right down at the molecular scale now. So I think one of the things that's sort of a long time could you make this is kind of the analog of a 3D printer, but operating at the level of individual atoms and being able to construct any kind of, any object made of atoms and so on. I think in the end that will, that will be a thing that will happen. Whether we will think of it as biology or synthetic biology, or whether we'll think of it as some kind of molecular sort of nanotechnology kind of thing, I'm not sure. I would tend to think more, more the latter. It really depends how much we use the mechanisms that we've got from sort of the history of life on Earth to build those molecular objects and how much we're building things from scratch. You know, do we actually use a ribosome to assemble our kind of protein like thing? Do we actually use things like proteins or do we use quite different kind of designer molecules that don't happen to have that same structure that has evolved for life on Earth? But you know, I think one of the things that will be sort of the, the ultimate sort of story is that you can sort of assemble anything out of atoms. Just as we can do, you know, a certain amount of precision manufacturing, we can have little, you know, we can have, for example, a 3D printer that lays down new material in tiny granules and things like that. We can imagine something which lays down new material level of atoms. There are processes that do that. Some sort of, There are. If you, if you have, in a vacuum, you just have a source of atoms and you're, you're sort of having the atoms accelerated with an electric field, for example. You can move that atom from this tiny source of atoms and it's kind of streaming to the other side and assembling themselves on a surface. The process called sputtering, for example. That is where people do that, where you're sort of assembling a surface by just having this trickle of atoms fall on it. But being, but it's a very slow process, being able to do that kind of more like the way biology does it with these kind of. Rather than having atoms just sort of being launched through the vacuum, so to speak, having little tubes that just sort of deliver the atoms to the right place is something where one can imagine that happening much more quickly, as it does in us as biological organisms, where at every moment we're assembling new molecules, we're putting atoms in different places. That's kind of how we, how many of the processes that go on in biology actually work. So, you know, I think it is quite within the realm of possibility and likely that we'll eventually know how to sort of assemble things at that atomic and molecular scale. What will be the point of that? Well, there's kind of a current computer, for example. Every bit in its memory corresponds to, I don't know, maybe 100,000, 10,000 to 100,000 electrons. So there's a certain room to get smaller. Although by the time every bit corresponds to just one or two electrons, there's enough kind of randomness associated with quantum mechanics, associated with the fact that computers are operating at room temperature, where everything is being jiggled around by heat by sort of the motion that makes that temperature, so to speak. So by the time you get down to, you know, oh, it's only two electrons storing each bit in memory, it has to be a more elaborate system that involves error correction and all kinds of things like this, because that's just not enough electrons to be sure that they weren't sort of kicked randomly out of where they should be. But there's a decent amount of room to make things sort of smaller and faster and so on. And probably the three dimensionality thing is even perhaps a larger effect. There's also the challenge. Once you have all of that structure, how do you program it? How do you get it to do things that are useful to us humans? Yes, we can get it to do things that are computations that are just happening anyway, but to direct it to do things that are useful to us humans, well, that's a story of kind of how do you make a computational language that kind of bridges from what we humans want to get, want to tell the computer to do to what can actually be happening down at the level of those atoms and molecules and so on. And that's a challenge which is still not, not met, particularly when it comes to lots of operations happening in parallel. Sometimes when the operations, it's all the same operation just happening to a whole bunch of different numbers, let's say, in parallel. That's what GPUs do, and that's something that's decently well understood at this point. But by the time sort of lots of different things can happen in different places, that's a more challenging situation. It's a situation rather similar to what happens in our physics project when we're looking at different parts of space, time and things like this. But it's the story of how one does kind of human connected programming on those sorts of things is a story whose end is definitely not yet told. But when it comes to, let's say we've made these molecular scale objects, we can make faster computers. But I think perhaps the most important thing for us in the immediate term is that we can make things that interface to biology. That interface. If biology is operating as sort of a molecular scale computer, and if we have our own sort of engineered molecular scale computers, we can expect to sort of interface them to biology. So we do that in a sense right now with things like drugs. Drugs are molecules that are typically particular shapes, for example, and those molecules will fit into particular places where there are molecules that we care about affecting inside us or other biological organisms and so on. They'll sort of fit like puzzle pieces into that particular spot in some other molecule, and they'll make that molecule more active, less active, whatever else, and have some medical effect. Well, we can expect that when we have kind of made to order molecular scale objects, we can have ones where it isn't just something that sort of just fits in a slot, it's something where it can fit in a slot and then it can have all kinds of computational operations and it can compute, oh, I'm going to run a machine learning algorithm right inside this molecule to decide, is this a cancer cell or not? What should I do with it? We have sort of very distributed versions of that kind of thing operating, let's say, in our immune system. But we can imagine an engineering situation where we've actually created this sort of molecular scale computer that's doing something at the level of individual molecules. And I think that, that when it comes to sort of these molecular scale things, I think one of the things that will be most significant to us is sort of connecting them to our biological selves to be able to do things that sort of do engineering kinds of things operating in connection with what we biologically are able to do. Now, presumably what that will mean is eventually there'll be sort of a bypass to lots of things that we're doing biologically. You know, if some particular organization and your body is not working up to snuff, so to speak, then you'll be able to sort of attach this bypass to it. That will be its own sort of separate engineered piece of molecular system. And it will be sort of straightforward to go in and attach that bypass. It won't be sort of a surgical thing where you, you know, you open the patient up and then connect actual sort of things you can pick up in your hands and do things with. It will be more at the level of individual molecules where you have specified. Okay, you've got all these molecules that they're in some little test tube or something. You've programmed all these molecules and that one is supposed to go here, that one goes here. They assemble themselves in this sort of complicated puzzle setup. You kind of, you eat the pill or whatever else it is, it gets absorbed, it goes in your bloodstream, it gets delivered. Well, I'm not sure how well that works because maybe it has to, maybe it has a hard time getting out of the capillaries and so on. But in any case, you somehow get the actual molecules, the sort of the computable molecules to the place you want to get them, and then they start assembling themselves and make the thing you want. And by the way, when we, you know, even in. It's sort of remarkable when it comes to, I don't know, stem cells, things like this, all kinds of other biological things you can sort of just sort of pour into a biological system and they'll kind of sort of collect themselves in just the right place by virtue of the fact that they'll only attach to particular molecules or whatever else. So anyway, a few thoughts about. About that kind of synthetic biology. I mean, I suppose there are other things. There's a question of can you make different kinds of, let's say, chemicals using essentially biological mechanisms? For a long time it's been typical to put, let's say, different genes into an E. Coli bacterium or something and have big vats of those things and use that to make certain kinds of drugs. I know insulin is one common example of that. Just by sort of having what would otherwise be a standard biological organism that's just producing protein molecules, produce the particular protein molecules we want. Well, you can imagine having something where it doesn't just produce protein molecules, it produces some other kinds of molecules. It's fairly typical in proteins that you can have these kind of cages where other atoms go in, like in hemoglobin in our blood. There's sort of a cage that's just the right size for an iron atom and that sort of gets attached there. And one could imagine something perhaps where one has created sort of a protein structure that has just the right kind of little tunnel template type thing to assemble a certain kind of molecule. That's what one wants. That isn't a molecule, that is a protein molecule. It's some other kind of molecule. I don't think that's a thing. I think that the cages that exist in sort of naturally occurring proteins, as far as I know, are just sort of individual atom type cages. But I don't think there's any obvious reason why one couldn't have a more elaborate kind of template in a protein molecule. And that will be a way to make other kinds of chemicals. Where? See, because when you make a chemical, usually when you do chemical synthesis, you're saying, oh, we're going to have a chemical reaction that means these molecules that sort of floating around and wiggling around in all sorts of different ways. For example, in a liquid, they're kind of bouncing around randomly and these two molecules, when they get near each other, they have to be in exactly the right orientation and so on to react in the way you want. And that will only happen with some frequency that might be quite low. You can have catalysts, for example, like solid catalysts, where these molecules will sort of attach themselves to the surface of the catalyst and that will align them in a particular way. So when the next molecule comes along, it has a better chance to find the other molecule in the right orientation to have a chemical reaction. But in biology, with enzymes and things like that, there's a more elaborate kind of way in which molecules are oriented correctly so that chemical reactions can occur. And it changes by huge factors the rate at which chemical reactions occur in biology. Well, you can imagine the, the, you can, you can do the same kind of thing. You can imagine things where sort of on a, on a per molecule basis, you're sort of building this machine that sort of connects molecules in just the right way. And that's sort of another, another sort of synthetic biology kind of kind of story. Let's see. Yes. So Peter is commenting on, talking about AI designed proteins that do biocomputation. Yeah, well, I think that's, you know, one question is, did biological evolution get the best protein for doing this or that thing? Maybe not. Maybe we can do a more efficient search than biological evolution was able to do. There's a lot of critters that have lived in the history of life on earth, so there's a reasonable amount of choices that have been tried in the course of biological evolution on earth. But biological evolution has one serious, one could even say killer problem, which is that if you make an organism, if you're trying to get to this amazing organism that has these complicated wheels or whatever else, well, you have to go through an organism that has sort of, is only a small change from the organism that we have today. And the chances are you won't get to the amazing organism in small incremental steps. If you happen, you know, be able to change the genome and just get to the amazing organism and not have to go through any intermediate thing, well and good, but most likely you'll have to make small incremental changes. And the problem is that getting sort of halfway there, the organism won't survive. The organism that has kind of the half assembled wheel or something just won't be able to get around. It's only if you could get all the way to the full wheel, so to speak, that the organism might be more successful. And so biological evolution, it really, everything it reaches has to be reached incrementally and that. But when we do sort of engineering from scratch, we can imagine just saying, I want to start from Nothing. I'm going to design a protein that does exactly what I want and I don't have to have intermediate stages that are viable that will make an organism that won't just immediately die. So in a sense we have a big advantage over biological evolution in that respect. We have a disadvantage in that there's a lot of organisms that have lived. And so there's sort of a big factor of things that have been tried. And it is not. It is not. I think it's still. Let's think. I think it's like, oh, gosh, I worked this out multiple times. Why do I remember 10 to the 40th organisms maybe have lived? I think that might be right, might be wrong. I'm sure it's in my book New Kind of Science, but I've forgotten the answer. It's a decently large number of different individual organisms, mostly microorganisms, that have lived in the history of life on Earth. But I think the numbers, while that number that I just quoted is vastly bigger than you can achieve in actual operations on a computer today, those numbers will at some point converge. And when we'll be able to sort of simulate, when we'll be able to explore this sort of computational universe of possibilities at least as efficiently as biology can do it without this issue, that one has to always have this sort of incremental success that one has to have in biology. So I think it's quite plausible to get to things that biology could never get to, things that are very disconnected from the way that biology is today and are not reachable by incremental change. Let's see the question here. Well, gosh, there's a question here from Kelly about. Okay, let's see. I see from Peter here in the case of life that all these various processes which evolve sort of co. Evolve with each other. And saying that would be hard to reproduce. I think there's sort of this question of could we replace just this one component and leave all the other components the same? Or for example, maybe there isn't really a way to just replace that component with something more efficient or whatever else. The only way that you can do it is by making changes to sort of what it attaches into. Kind of reminds me of lots of things that come up in things like software design. Can you. You've got this particular part of a, let's say a user interface you want to change. Oh well, you can change that part, but then it will no longer fit in that place on the page. And so the container into which it Fits has to change. In other words, you can achieve the big objective, but if you make this incremental change to one piece, it won't fit in properly to the the other engineering structure that you built. And so, yes, I can imagine that happening in the case of things you're trying to fit into living systems, But I can also imagine it being sort of a plug compatible change to a living system. I'm not sure. My guess is that biological evolution has achieved a lot of very clever things, but that they're not the only ways those things could be achieved. And there may be advantages to other ways of achieving them that weren't ones found by biological evolution. Let's see. Callie here asks, how do I think space travel will change, improve as technology advances? Will it become a regular form of transportation at some time in the future? I always think in terms of technology prediction. Space is one of these awkward cases. If you look back in history when airplanes first existed 100 years, a bit more than 100 years ago now, people sort of wondered what would they be useful for? And the idea of transporting passengers around was not high on the list. It was, oh, we can deliver the mail that way. We can take photographs, we can take aerial photographs. Soon it was, we can drop things as bombs and so on. We can do, you know, we can do cool aerobatic displays, things like this. But delivering large scale cargo or passengers wasn't a particularly early thing that was imagined for, for airplanes. And of course things changed because airplanes started to be able to go much larger distances. They started to be able to fly higher in the stratosphere and so on. And they had been, you know, early airplanes, even early sort of commercial planes were really bumpy because they were flying, you know, right down in those cumulus clouds or whatever else. And there came a time, when was it in the 1950s, I suppose, when airplanes, particularly with jet planes and so on, they started to be able to fly above the weather. And it was a much smoother ride. And it wasn't a ride where sort of everybody on the plane was going to get air sick, so to speak. So, you know, there are details like that that can affect the viability of one of these kinds of things. But I think space has always seemed to me an interesting case where it's like, what's really going to be the critical application for space? Very early on there were communication satellites that had been a thing in more recent times. There's Earth observing satellites, there's both. You know, one can get, you know, at this point, one can get a reasonably high resolution picture of any place on the earth once a day. You know, the daily picture of every place on the earth. I don't think one knows yet very large scale applications for that technology. There are applications at the government level, at the level of various kinds of financial and agricultural prediction kinds of things, but there isn't really yet that hasn't emerged kind of the great consumer application of the daily photograph, so to speak, of the surface of the earth. And you know, that's an example of something from space that, you know, it could also have been done with drones if you, although it's easier to do it from space, but it's not something where we yet know what the sort of the, the big consumer application is going to be. And there are plenty of these things where if you look at the course of technological history, it's sort of unclear how it goes big, so to speak. I mean before let's say web search existed, there were things that would search technical articles, the abstracts of technical articles. I used those things back in the, oh, mid to late 1970s. There were pretty good systems for searching for sort of technical abstracts. And then there were, you know, kind of libraries where you go look up information. But the idea that there would be sort of a search engine and that would be a very popular, widely used technology didn't really arise until such things existed. If somebody had done kind of the market study of is a search engine going to be worthwhile? They might have said, oh no, there are only such and such a number of reference librarians in the world and there's such and such a number of reference queries that get made every day and not enough people care about this. But once the technology actually exists, then one can see how convenient it is. We'll probably see the same thing again with these kind of LLM based technologies for summarizing information. I mean from WolframAlpha, we've had for a dozen years now the ability to ask a question in natural language and compute the answer when the answer can be computed on the basis of kind of computable knowledge that exists in the world. But doing the thing of sort of taking even the non computable textual knowledge in the world and being able to deliver it. That's sort of a new thing and it's different from oh, here are a bunch of links, go follow them, so to speak. But people aren't yet used to, you know, it's only been a few months that this technology has reasonably well existed and it still isn't Sort of doing real time search of the web. Nor is it yet connected into WolframAlpha and things like this. But that will become something where people will eventually say, oh yeah, it's obvious this had to work that way. But so when it comes to space, there's sort of this question of what's it going to be useful for? Let me give another example back. Oh, I don't know. Even in the, well, 1980s, certainly, you know, I was, when I had to drive from place A to place B, it was like, oh gosh, this is terrible, you know, I'm going to be two hours, I'm going to be stuck in a car, I've got nothing to do. You know, maybe I listen to the radio, that's the best I can do. Or maybe I have a tape or something, or maybe I dictate something. I used to do that in the early 1980s as when I had to drive from here to there. I would, would dictate things that could get typed up separately and so on. But it was very much of a pure, I'm just wasting time when I'm driving. But then sometime in the, in the 1980s, you know, I started having cell phones and then, you know, I'm driving from here to there. Well, I've got some list of phone calls I'm going to make and I'm happily making my phone calls. And you know, it's different scenery. I'm not just sitting in one place, I'm seeing the scenery go by and I'm making my calls and I'm a happy person. And the fact that it took a bit longer to do that drive doesn't really matter to me. It's not something where I'm saying, oh gosh, I need that, that scrapper. It's really important to reduce that amount of time. So you know, when it comes to, oh, is it important to have a supersonic plane, for example, is it important to really reduce the time that it takes to get from place A to place B? It's a complicated story. I mean I, I once had the opportunity to go on the Concorde from London to New York actually, and it was cool. But you know, did it profoundly affect my, I mean I, I, in that particular case it was one of these situations where, you know, I said, well, I've got this thing I have to do in London, I've got this thing I have to do in New York. The number of hours between them is not enough to take a commercial plane. Let's, you know, to take a Standard plane. Let's spl. Splurge and take the Concord, so to speak. And then I can. I don't have to rearrange these two things, but it was sort of a corner case. And so the question is, let's say that we can get from place A to place B much faster than we do right now. You know, what effect will that have? You know, in some sense, you know, there are details like, you know, you travel from place A to place B and the. You change time zones and you get nasty jet lag. And maybe if you could get from place A to place B in two hours rather than in eight hours, you would be able to adjust your sleep schedule differently. And it would be a better experience. I don't know how big an effect that is. You know, there's this question of if you could get from A to B in much shorter time, you know, how would that affect things? Now? Maybe. Maybe that would mean that people would travel much more. Obviously, the fact that there are planes letting people travel from place A to place B fairly quickly has increased by huge factors. The number of people who travel from place A to place B when they had to use boats or trains or whatever, there were, for many situations, many fewer people making those trips. So, you know, there's this question of if you could get from place A to place B with the, you know, hypersonic plane, that. Or the spacecraft type thing, would that be a big deal? Would that really change things? My guess is that there will be unexpected changes. There will be unexpected advantages. If it comes to pass that those things become sort of really easy to do, There will be sort of unexpected reasons to do it. In the case of the Concorde, for example, I think other than the kind of swankiness value of it, it wasn't clear that it really had incredible productivity kind of increases. And of course, it existed at a time right before you could just sort of open your laptop on the plane and keep doing what you'd been doing previously. So I think, you know, for the time being, it's kind of a space tourism type thing. And I think that one wonders, sort of what the comparison is between sort of space tourism and ocean tourism and going in submarines and things like this and seeing the deep ocean, which will be kind of cool to see as well. There's a certain kind of. There's a certain attraction, I suppose, to seeing the planet from. From very, you know, from. From far away and such. Like, I don't know how. How big, other than for sort of the. The. The swankiness and novelty value of it. I'm not sure how big a bigger thing that will be now when it comes to sort of what can you do in space? What can you do, for example, in a microgravity environment, in a weightless environment in space that you can't do on the surface of the Earth? People have talked about all sorts of things from growing perfect crystals to doing various kinds of biological things in those conditions. I don't know how significant any of those things have turned out to be. I think it's kind of a bit of a downer that we humans were not well adapted to exist without gravity. Our bones stay strong because we continue to walk on them and use them in gravity. And if we don't, we have to make a big effort to sort of do exercises which simulate the effects of gravity so that our, our bones and things like that stay, stay strong. So I'm, I have to say I'm, I continue to be very curious what the sort of big applications of space will end up being. I think there are others one could certainly imagine. I mean, there are lots of communications related things that's become, you know, cell phones didn't exist when, when space was first being, being explored. And that's clearly something for which there are pieces to the, to the story of using space. There's sort of a problem in that you can't get from a handheld cell phone. It's, you can't with, with batteries as they are now, and antennas as they are now, you can't really send sort of kind of, you can't have a, have a kind of conversation with a regular cell phone going to a satellite in orbit. You can with a sat phone, but sat phones have big antennas and things like that. It isn't yet possible with, with, with a regular, you know, have your iPhone do a phone conversation. You can, you can now start to do texting, which is lower bandwidth and so on to satellites, but not yet the kind of thing necessary for voice communications. But maybe that isn't important because, you know, things like Starlink have these bigger sort of base stations that communicate with satellites and then can locally on the ground, like a cell phone, communicate with local cell phones. But again, it's the, I think that, so, you know, there's this sort of communication story. There's also a story of things like servers. You know, right now we have server farms on the Earth and sometimes a big part of what's expensive about server farms on the Earth is they need a bunch of electricity coming in and they need a bunch of cooling to deal with the fact that the, that the computers generate a lot of heat. Some people manage to set it up so that they're using, you know, the cooling is a bit simpler and you don't need a big sort of H Vac system and so on. And people put, you know, data centers in places where there's a ready source of, you know, hydro, hydroelectric or geothermal energy or something like this. But still generally you need a bunch of electricity to supply a solar farm. Well, in space you, you unfurl your solar panel and you've got, and the, you know, the sun is bright and you've got a bunch of a source of electric power. And also because space is effectively cold, you have the ability to sort of get rid of the excess heat. And so, you know, there could very well be a strange time in which it is cheaper to basically fly on satellites. The things that you have now in silver farms on the Earth that you, you know, you've got. It's sort of a, a better story in terms of get the electricity from, from this, from photovoltaics, from, you know, from, from the sun and dissipate the heat just without explicitly having to do that with, with H Vac and, and so moving, moving the heat around in, by, by explicitly sort of pushing, pushing air in one place or another. So you know, one of the things that could happen is we could see a generation of, of of servers that are in space rather than on Earth that it might be a better way to do it. What other kinds of things will there be? There's been another one which was a surprise was gps. Wasn't obvious that a space based navigation system would be a thing. That wasn't one of the things that was kind of on the radar when people were talking about space in the 1960s and how space will be used. Communication satellites were understood, but not gps. That was a thing that sort of came later. There were land terrestrially based navigation beacons which have now mostly been switched off I think. But the space based solution wasn't really one that had arisen. So there are things like that that one could imagine. I'm not sure this is the thing where, when it's something where if we look at computers and we look at what did people think computers will be used for when they were first computers? Well, people said oh, there'll only be a need for five computers in the United States because they imagine they're doing calculations for ballistics. They're doing calculations maybe for various kinds of technical Calculations and so on. The idea that computers would be used for word processing, or that they'd be used for social media, or that they'd be used for all sorts of other things, those ideas just hadn't arisen and wouldn't arise until computers were powerful enough and cheap enough that those use cases became realistic. Same thing with one of the, at first, more bizarre inventions was the cell phone camera, where it's like, really, you can, you know, people say, I'm having a phone, why would I want a camera in my phone? Well, turned out to be a pretty good idea because people have their phones in their pockets. It's convenient to have a camera in your pocket. But all the sort of cost curves have to get to the point where the cost of transmitting a photograph through the cellular network goes down low enough. The cost of the memory and the phone, the camera, et cetera, et cetera, et cetera, everything sort of has to converge to the point where that makes sense. And so, you know, knowing what will happen and, you know, let's say, let's say it was really cheap to put things in orbit around the Earth. Let's say it was really cheap to send things to the Moon. What would then happen? You know, perhaps there is some feature of lunar regolith, moon rock that is really convenient. Maybe, you know, it has very sharp, you know, on the Earth, sand gets eroded by the atmosphere and by, by oceans and things so that pieces of sand are not incredibly sharp. On the Moon, the analog of sand is incredibly sharp. Maybe there is some place where it's really useful to have these incredibly sharp pieces of sand. And if you could get, you know, a ton of lunar regolith for a small amount of money, people would be regularly importing that onto the Earth and saying, look, you can use these very sharp pieces of sand for some incredibly worthwhile kind of industrial process or something like this, which nobody would have thought about unless you could get a ton of lunar regolith for very little money. And it would have been a crazy thing to even consider. And so there are questions like that. It's an interesting sort of exercise to try and think through what are the conceivable things that might lead to kind of, that might, might, might lead to sort of really dramatic uses for space. I mean, when it comes to, oh, let's put a colony on the moon, let's put a colony on Mars. I mean, again, it's hard to know exactly what the sort of the big payoff of that is going to be. You know, I tend to think the idea of make the backup civilization on Mars type thing won't play quite as well as one might imagine because there'll be sufficiently many, you know, it's kind of like, well, it'll all be separate. Well, except it'll still have computers that are connected by network connections. And the computer virus that wiped out all the computers on Earth is still going to infect the Martian computers. And the, you know, the, oh, we didn't think of the fact that when we sent that package to Mars it had this new form of, of, you know, prion dangerous biological agent that we didn't test for. And so oops, we, you know, that ended up infecting the colony on Mars as well. I think that having sort of the, a perfect separation between those or, or for example, when you say, you know, maybe there'll be some terrible socio political thing which will happen on Earth and oh, but it will be separate somewhere else. Well, yes and no, because people will still be interacting presumably with folks here on Earth, so to speak. And whatever it is that affects the thinking on Earth is likely to affect the thinking on your sort of separated colony as well. I mean, I think that, you know, history tends to suggest that things, you know, the colonies were never that separated from, you know, sort of the origin, so to speak, at least in most cases. So I'm sort of let, I'm not sure how that will play out. Let's see, I'm seeing a bunch of comments here. Yeah, DES is commenting. When helicopters were first developed, people thought they would transform cities and be our new taxis. But they weren't, you know, helicopters were developed what in the 1940s, 1950s, the first helicopters. They're still kind of special case things. And you know, it turned out they were hard to fly, they were expensive to maintain, they were expensive to build. And you know, people thought, well, what about quadcopters, things like that? Well, for a long time those weren't possible because you couldn't get electric batteries that had enough density. You couldn't get flight controllers that would, would keep the things stable, would, would be able to, you know, run the rotors faster, slower to keep the thing stable. But then suddenly, what was it like 10 years ago now? Drones came into existence and now they're, you know, they're, they're a common thing and there are many use cases where it's like, how could you possibly have that, that thing that's surveying this area from a height of 200ft? You know, that would be a really expensive thing to Achieve. But no. Now, with drones, it's easy to do, but the, the power curves and so on for drones are not such that we can make drone taxes. Yet. I've seen some sort of prototype examples of that. I think I have yet to see anybody actually fly in that prototype. I've seen the prototypes. I've even seen the prototypes flying. Don't think I've seen anybody actually flying in one. But presumably in time, if battery densities, power densities improve and things like that, there will in fact be drone taxis, so to speak. And if their reliability is good enough and so on, people will routinely start using them. And that will certainly change all kinds of things. I mean, just as the existence of cars made suburbs possible, people didn't all have to be sort of clumped together in the city, where transportation was easy, but could be more spread out in the suburbs. By the time there are drone taxis, so to speak, maybe there will be sort of things can spread out even further. People were predicting that back in the 80s, 1980s, and didn't really happen. The kind of excerpt concept you might have thought with the pandemic and lots of geodistributed work that would have developed, but it hasn't really developed that I've been able to see. And I think again, if the drone taxi becomes cheap enough, helicopters, it won't be helicopters, it'll be quadcopters and things like that and electric ones and so on may become very, very common and may have lots of effects on kind of the fabric of how things are set up. But yes, it's very hard to predict these things. It's very hard to predict that helicopters wouldn't quite make it. You know, I don't know by what factor they fail, so to speak. But I do know that, for example, the complexity of a helicopter and the amount of maintenance it needs and so on tends to make it very expensive. Let's see. I see a comment here. Robert Heinlein suggested in his books from La Magi, saying. Robert Heinlein suggested in his books using suborbital rockets to travel between destinations. Would such an idea be too expensive? Would it be feasible? You know, the biggest suborbital, well, sort of use case, which fortunately has never really come to pass, is intercontinental ballistic missiles. And being able to kind of launch a rocket that, you know, goes almost into orbit and then comes down on the other side of the earth and blows something up. Now, you could imagine if the cost of space travel became low enough that you could do the equivalent of an icbm, but you could do it for package delivery, for example. And people talk about, well, what about medical deliveries of transplant organs, for example, where it really matters that they were harvested one place and then an hour later they're on the other side of the earth, maybe. I tend to think package delivery is a more immediate thing because of the G forces involved in the launch and re entry and so on. But maybe there's a way to avoid that and have the happy passengers there too, not being subject to very high G forces. I'm not sure. I think it's hard to know just what packages you really need to get delivered that quickly. You know, I would say that for me, for example, you know, I used to get package deliveries of all kinds of packages, stuff every day. I don't really get that anymore. Why not? Well, because it's all electronic, you know, I don't need physical documents. I don't need physical stuff nearly as much. It's much more. I have my universal computer and I'm just loading up software or data onto that computer. And that's transmitted without sort of a, A, you know, a. That's transmitted by electrons, photons, whatever else, but it's, it's not transmitted by moving a physical object from here to there. So I'm, I'm, you know, it's, it's challenging for me to see what kind of, for example, package delivery, where you're delivering it from, you know, New York to Singapore or something. What kind of package delivery is really important to happen in half an hour? I'm not sure. I think that, you know, I'm not sure whether, you know, if it got cheap enough, then all those ships that go, you know, ply the Pacific and things like this will, you know, you might as well just say, I'm ordering my thing, it's going to get made in some factory on the other side of the Earth. I'll get delivery of it really quickly. I'm skeptical that that's really going to work out, but eventually, perhaps it might. I mean, even the delivery of packages from your average Amazon delivery or something, delivering it by drone, that hasn't worked out. I think I saw the very first demo of that kind of air delivery of Amazon packages. But it wasn't, didn't look very impressive, actually, the very first demo, and it didn't seem to play out as a thing that's been important. Now, maybe there, maybe there are outlying places. I think there are places in, where population densities are low and infrastructure is lacking, where. Yes, absolutely. Drone deliveries make sense. But as a very routine kind of thing, it hasn't happened yet. Just a couple more comments here. Okay, Doug. Doug Doe comments. I think the cost and safety risks associated with space and underwater ocean tourism will keep them from ever becoming commonplace. You know, things get safer. You know, commercial air travel has gotten much, much safer. It's one example that I think two very commonly quoted examples are general anesthesia and commercial air travel are both things that over the decades got dramatically safer. And I think people say the number one reason tends to be better sensors, better ability to know, okay, you're flying the plane, some little thing is going wrong. Okay, you can, you know, a sensor notices that you can take, you can do something about it rather than, oh, a crack is developing here, nothing notices, and then some dramatic problem occurs. So I think, and I think that the, this. What, what seems unsafe at first can potentially get much safer over the course of time. It's sort of as the engineering gets more and more polished, as the ability to sense trouble more quickly gets better, gets easier to, to improve the safety. You know, there's a thing that is. It always used to be said that, well, after the Challenger disaster, my friend Dick Feynman actually was responsible physicist who was part of the Challenger inquiry had this kind of claim that 1 in 50 rockets blows up and there's nothing you can do about it. That claim was. Caused all kinds of trouble in the, at NASA and things like that probably for many years afterwards. I'm not sure. I mean, I remember him showing me the data that, from which he came to that conclusion. But. And it had been empirically the case that, you know, one in 50 rockets blows up. I don't know if that's still true. Rockets are really tricky things because you're, you're trying to keep this stuff burning and you have to keep it right at the point where, where it's, where the material is, is, is just combusting and things like this. And you end up with all these complicated tubes and assemblies and so on. But there are plenty of complicated tubes and assemblies and, and lots of kinds of machinery that end up working in a very smooth way. So I don't know if it's true that if, if it's true that there's. I don't think it's a constant of nature that one in 50 rockets blows up. And it's interesting, I haven't looked at the data on reliability, but I suspect that there's no fundamental reason why one can't make these things safe, so to speak. And there's plenty of situations in which sort of one is in a very. Is in an environment. I mean, any plane flying at 36,000ft is in an environment that's incredibly cold, too low a pressure to sustain human life, and so on. And yet it's something which has been sort of successfully dealt with. Well, okay, I think I'm. I'm. Just. Let's see. Lorde is commenting that the perspective now on what's possible for travel is really different. Oh, I see. For. For somebody like me, who's an old fogey, it's a different perspective on what's possible in travel than for younger generations. I'm not sure how true that is. I think that we're all taking the same. You know, we're all taking planes to get from here to there and so on in many parts of the. Let's see. Okay. BLH is commenting that air travel, cell phones, computers, all these technologies went through a long period of being luxury goods that only the richest people on earth could use. And maybe the same will be true of space travel. Yeah, different things have advanced at different rates. I mean, air travel used to be this luxury thing. It used to be a thing. I remember when I was a kid that if you were going to go on a plane, you kind of put on your best clothes and looked very. Wanted to look very spiffy. I think that was one of the things that fell by the wayside somewhere in the last few decades. And I think that the thing with cell phones, I mean, I remember first. Well, there were radio telephones before there were cell phones. And radio telephones were only for the fanciest people, so to speak. Then when cell phones came in, at first it was kind of strange. I mean, there were things like you could rent cell phones when you rented a car. And I remember probably 86, 1986, 1987, first doing. Routinely doing that. I don't think. I think I owned a cell phone by 1988. And then I then sort of went on this curve of getting the. Always the fanciest cell phones. And for a while, cell phones were sort of a thing that only. Only a few people had. And then. Then the sort of. The inflection point came when. When sort of almost everybody had them and young people had them and kids started having them and so on. And that did take, yeah, about 10 years. In the case of cell phones, I think that computers, on the other hand. Yeah, that's a funky one. Because personal computers. Let's see. First, personal computers were kind of rather hobbyist. And they weren't that expensive. They were just hobbyists. They weren't things that people generally. They weren't sort of smooth enough for people to generally use them. And the computers that people used for work were big, inexpensive, and cost millions or later hundreds of thousands of dollars. And I think that the was sort of a different case because there was hobbyist stuff that wasn't expensive, but it just wasn't interesting to most people. And it was only in, what, 1982 or so with the PC and so on that it started to be the case that the it sort of was a convergence between the fairly cheap sort of hobbyist stuff and the stuff that was actually productive to use. And yes, there was a period of time, yeah, it was probably, you're right, it's probably about a decade when computers were still kind of very much luxury goods. I think that one of the things that's amazing about electronics is how mass producible it is in the sense that, you know, once it exists, it gets to be fairly cheap and it gets to be the case that sort of, you know, billions of people can afford cell phones, even though there are, you know, there are other things, I don't know, areas of medical technology, for example, where there's still a much steeper cost curve and where sort of, who can. The. It is not as broadly accessible. So I don't know. In the case of space travel, one would assume the same kind of curves would happen as happened with air travel, where that really was a. What it must have started by the. In the 1920s, maybe it was starting to be some kinds of. Maybe 1930s, I don't know when the first commercial sort of scheduled planes were flying. Maybe maybe 1930s. By the 1950s, it was kind of a business person's tool, but still kind of luxury as far as. As far as sort of individual people were concerned. By the. By the 1960s, it was pretty routine. As for individual people, I mean, I remember, you know, just the way costs work. It just the. All the differences of these kinds of things. I remember when I was a kid, must have been, I don't know, mid-1960s. I remember I went with my parents on a vacation to France and you drove the car down to somewhere in the south of England. And it was cheaper to drive the car onto a cargo plane that flew it across the Channel than it was to put it on a boat to go across the Channel, presumably because the cost of gas was low enough and so on. But it's, you know, that would definitely not be a thing today. You know, the cost curves have just evolved differently there. But I think this whole question of what. Yeah, I think in the case of air travel, arguably it's kind of mainstreaming took, you know, took quite a few decades. And I mean, I suppose and then there were all kinds of constraints that, you know, the discount. Yeah, I think there may have been things that were more of regulatory origin that had to do with, you know, which. Which airlines had, had, were. Were allowed to fly, when could they get slots at airports, all this kind of thing. And then that was. What was that? That was in the 1980s, beginning of the 1980s, the deregulation of air travel and the discount air carriers. And that was again, an economic, complicated economic thing because it had been the case that people thought you had to charge a lot for each ticket and not that many people will fly, but overall it will be a commercially viable thing. And then there was sort of this different cost point where it's like, let's get lots of people to fly, not charge much for a ticket and have fewer kind of amenities around. Around flying. And that can also be commercially viable. And maybe that, maybe the reason that it didn't mainstream earlier is for these regulatory reasons rather than because of the technology of the whole situation. I'm not sure. Anyway, I need to run off to my day job here, but nice to chat with you all and look forward to talking to you again another time.