Hello friends. One of my favorite parts of co hosting this podcast with Daniel is that it's given me the chance to meet and interact with a bunch of you. I've really enjoyed learning about your backgrounds, your interests, and some of you have cracked me up in some of the emails. You're a funny bunch, and in particular, I love getting your questions. Y'all ask some incredible questions and often there are questions I had never thought about before, and Daniel and I love that we get to find
answers to questions that keep you up at night. So today Daniel and I are going to tackle three questions that we've received from listeners. And we take the responsibility of finding answers to your questions quite seriously. So after we have an answer to these questions recorded, we check back with the listeners to see how we did with the answers. Essentially, we let you all grade us, and if we fail to give a clear answer, we're gonna try again, and in this way you all can help
us learn how to explain things even more clearly. So thank you. If you want to send us a question, you can either join us on our discord channel or you can send us an email at questions at Daniel and Kelly dot org. We hope to hear from you, and welcome to Daniel and Kelly's extraordinary universe.
I'm Daniel, I'm the particle physicist, and I love getting your questions.
I'm Kelly Wienersmith. I study parasites, and as you already know from the opening, I love getting your questions too.
Do your kids ask you science questions you can't answer? Kelly?
Oh yeah, So my daughter asked me a good science question that I sent to you the other day, so I know the right people. And every once in a while she will ask a question that's like at a very deep level of why, and I won't know the answer and she'll stump me sometimes. But she also doesn't like talking to me about biology too much because she knows, which is such a bummer. But uh, is that.
Because your answers are too long? Is that why?
That's exactly why it is. That's exact exactly why we have Yeah, oh yeah. Do your kids ask you questions you can't answer?
They do sometimes ask me questions I can't answer, but they always stopped me after a few sentences and Hazel's favorite line is like, I didn't ask for a college lecture.
I mean, your dad's a college professor. That's what you're going to get.
And your mom too, Yeah, that's right, what do you expect? But it's fun. I love their questions, and I love the challenge of trying to answer it within that teenager attention span of like six seconds.
It certainly forces you to be succinct and clear. It's good, it's good fortice, yes exactly, but it's not naturally how I roll. But that's okay because with at least twenty minutes to answer each one of these questions, so we can go ahead and get into a nice bit of detail. Our first question is you know exactly the kinds of amazing questions that I hadn't thought of ahead of time, but I love getting a chance to think about. So the first one is about you know, soil on Mars
and what makes soil? And I just thought this was such a fantastic question, but I didn't know the answer. And so it's also a great chance to bring a friend on the show.
Hello, Daniel and Kelly.
After two Mars episodes, a question or two popped in my brain Mars does not have soil now, but if that was live a long time ago on Mars, could there be soiled deeper down in the ground. Also, if they used to be like on Mars, could that have created oil deep on the ground. Can single cells produce oil or do we need at least bigger life than that? Thank you for the podcast, Kind to your guards.
Yost Okay, So this sounds like a geology question, and lucky for me, I have a geology friend. He was my poraranteine buddy in the pandemic. So we're bringing onto the show Callen Bentley, who's an associate professor of geology at Piedmont Virginia Community College and he's co author of the free online textbook Historical Geology. Callen, what's up?
Hey, thanks for having me. I'm glad to be here.
We're happy to have you here. So I read this question and I remembered that I had a conversation with you once about what's the difference between regolith and soil? And I think I remember you just sighed and walked away or something. It was something like my sense was that, oh, these it's just jargon, But so what can you tell me what is the difference between soil and just dirt and regolith.
Yeah, so dirt doesn't really have a scientific meaning, but regolith does and soil does. And the difference between them is that soil has organic matter in it, which we call humous here on this planet, not to.
Be confused with the delicious dip with the heeny in it.
That's right, That is hummus, and there is a difference of one m here on Earth. Humus gets added from the top. So basically, like this time of year, the leaves are dropping off of many of the trees in the northern hemisphere, and that's basically a rich source of organic matter and that drops onto the soil and those leaves fall apart or they get tugged underground by earthworms and basically get mixed in with the rock, fragments and mineral grains that make up the other sort of solid
bulk of the soil. It's important to realize that soil actually consists of, you know, solid stuff, but also a lot of empty space which can be filled with either air or water depending on whether you're in a drought or it rained recently, or how deep you are on the soil. So you know, if you went and looked at the Apollo astronauts' footprints on the Moon, those are in regolith because there's no organic matter on the Moon.
We don't know about, you know, sort of thet of Mars as well as we know about the Moon, because we haven't been there and picked up samples and you know it brought them back, and you know, we've done a few sort of remote experiments. But the sort of mechanism of folding organic material into the you know, putative Martian soil would seem to be lacking and so at least in the present day now if it existed in
the past. You know, that's I suppose a possibility if Mars had a thicker atmosphere in the past and a more pronounced greenhouse effect, you know, perhaps there was life there in the terrestrial realm at that time that could produce organic material and add it to the regulith and turn it into soil. And it is indeed possible, as the listener asks, that those old soils could be buried under subsequent sedimentary layers, perhaps with zero organic content. We
have examples of buried soils here on Earth. We call them paleo sols, and there are a lot of examples of them. They have various characteristics that are signatures of the conditions under which they formed, just like sedimentary rocks contain signatures of the circumstances under which the sediments accumulated.
Do you make soil in the surface and then it can get buried And so you're saying, if you had life a long time ago, you would have made soil, and then life all died out, you continue to make layers, and that buries the old soil into is that paleosoil.
Paleo soal? So they drop the eye. Yeah, soils are a little bit weird. They call the soils themselves by these names that all end in sols, like arit asols and gelisols, and I don't know a bunch of them. Soil scientists are really into classifying things. They've like organized all of the planet Earth's soils into like nineteen thousand soil orders or soil series, and then those are grouped into like a dozen or maybe fourteen soil orders. Honestly,
it's not my area of expertise. The main thing that seems to be a driver for my sort of basic level understanding is that the climate really controls what sort of soil you get in a given area. So soils and deserts tend to be really jacked up in terms of their evaporate mineral content because water gets wicked through them, carrying material in solution, and then that gets precipitated as the water goes into the atmosphere, So they tend to
be very hard and calcareous. Soils in the tropics tend to be really clay rich because the most common mineral in the crust of the planet, feltzbar rots underwarm, wet conditions and it makes clay, so you get these bright red iron oxide stained clay rich tropical soils.
So Mars has red soils like that. Is there any similarity there or am I just reach in.
There's definitely oxidized iron in the what I would call regolith and sedimentary rocks of Mars. So yeah, that's a similarity that the iron there reacted with oxygen. And under what circumstances that occurred. I couldn't tell you whether that was in the open air, you know, whether it was submarine, or whether it was you know, in a fresh water system, or whether it was underground due to ground water. You know, there's a lot of possibilities there.
How much do we know about the surface of Mars. I mean, I know we've had rovers there for decades and they like pick up rocks and they drill into them. But half far like down, have we dug into Mars?
Not far? Yeah, there was an attempt a few years back to you know, basically drill the deepest hole yet dug on Mars in the service of installing a seismometer so we could listen for marsquakes.
Love that word marsquakes.
Yeah, And I don't think it got very far. I think it got stuck, and so it was sort of an abortive kind of thing. Kelly's nodding, so maybe she's more familiar with the history of that.
I think it was more than one problem one. I think things were more compact than they had expected them to be, so it's harder to get through. And then also it was having trouble gripping and staying in one spot. It got only a fraction of the goal of the depth that it was shooting for. It's just hard to work in space.
My Wikipedia research tells me that the deepest hole on Mars is nine and millimeters deep, which is not very impressive.
Oh man, So if there's soul on Mars, probably it's just bacteria. Uh that that's adding the like lify component to it. Is there anywhere? There's probably nowhere on Earth where it would be just like that. Probably anywhere else you'd also find like nematods and stuff.
Well, yeah, not anymore. There certainly would have been paleo environments on Earth when it would have just been microbial, and those would have lasted for a very long time for you know, the first several billion years of Earth history. You know, some of those microbes would be prokaryotic of course, and then eventually you carry out show up as well. But yeah, probably it would be unicellular, if anything big If could.
Having just unicellular organisms result in oil? Or do you need bigger stuff to get oil?
Oh wait, wait, we're going into oil now. I thought we were talking about soil. So have we dropped the.
S You dropped the eye and went to soils, and now we're going to drop the S and good oils?
Yeah, okay, So with with oil the story is a little different. It's a little more complicated. So when I think of soils, I am thinking of terrestrial regalith with organic material being added from the top and then gradually getting mixed in, but the organic content would decrease the deeper you.
Go, Holnd did just say terrestrial regolith? That means on Earth?
Yeah, thank you so much for asking that clarifying question about the words I'm using. What I meant was not underwater, not in the ocean, So I meant on the land, all right. So you know, my default setting would not be to call marine sediments by the name soil. I would call them sediments, and they might have a high organic content or they might not. But that is not what I'm saying when I'm talking about soil. So I'm talking about land based settings. So that's what I mean by terrestrial.
But you said terrestrial realith. You use the R word.
Originally it would have been regalith, right, and then eventually, sometime in Earth history it started becoming soil through the addition of this magical ingredient of humans.
This cleared up an argument Daniel and I had.
In the past.
Thank you.
It turns out you turn regolith into soil just by adding hummus or hemus.
You could add, yes, you could do the job with hummus or other forms of humous.
Bhemi is like magic, really, it sort of life giving.
The scientific community argues at meetings like a geological meetings like the Geological Society of America. There are periodically sessions about the terrestrial biosphere during the Cambrian and what they're not saying there is the biosphere on Earth. They're talking
about the biosphere on land. So we have a much better geologic record about what was happening in the oceans because that's a place where sediments tend to get deposited and tend not to get eroded, whereas the land is a place where sediments tend to get eroded and tend not to get deposited, at least in the long term sense. We do have terrestrial here again, I mean land deposits of sedimentary rocks, but they are far less common, fewer, and further between than marine eediments.
We were going to get back to oils, So.
That's basically what I was saying for soils, Okay, And yeah, basically we don't know when the humans started getting added. People argue about that, and they look at various you know, biotracers, geochemical signals, things, like that. As far as oil, oil is a liquid hydrocarbon cocktail that is formed due to cooking algae, cooking phytoplankton. All right, so I'm using algae
here in the most inclusive sense. But basically, you know phytoplankton photosynthesizing in the upper sunlit portions of bodies of water, usually the ocean, but potentially also you know large lakes and things like that. They capture energy from the sun doing photosynthesis, they lock that up in their organic molecules. Then they kick the bucket and they die, and if they avoid getting eaten, then they fall down and their little dead bodies accumulate on the bottom of that body
of water. They are likely to accumulate there if there's not a lot of things that are grazing them trying to eat them, and oxygen levels are relatively low. So if you bury this organic rich stuff and you warm it up, then you can cause chemical reactions to take place that produce the stuff that we call oil and the stuff that we call natural gas, which again is
a cocktail of a bunch of different ingredients. Button in the case of natural gas, they are in the gas state, not in the liquid state, So with accumulating that phytoplankton here on Earth. You know, there's certain conditions that we need to kind of go through to get that stuff and get it down to the bottom of the ocean, and then it has to be buried, and then it
has to warm up to the right temperature. So before we started our podcast today, I made a cup of coffee, and that's about the right temperature that you need to warm up your dead phytoplankton in order to get them to produce oil. If you don't heat them up enough, they don't make the oil. And if you heat them up too much, it basically it reacts away and makes other compounds that are not capable of flowing and being pumped out of the ground. So the happy place for
oil production is around one hundred degrees celsius. Okay, the temperature of an espresso.
This sounds kind of complicated and not so easy to arrange. How is it that we have so much oil on Earth?
Well, we would have more if it wasn't sidaran complicated, and you know, we have some, but we don't have an infinite amount. So it's these circumstances might sound really far fetched and unlikely to occur, but they have occurred, and if they hadn't, you know, we would probably be living very very different lives.
So Mars used to be warmer because it had flowing water at one point was it that warm.
So what I am talking about is not the temperature at the surface. And if if the temperature at the surface was one hundred degrees c, you wouldn't have flowing water, you'd have you know, water vapor right or you know, the transition between those. What I'm talking about is burial conditions.
So deep in the earth, and you know, there's usually some amount of overburden, some amount of pressure of overlying sedimentary layers weighing down on this sort of pressure cooker where these phytoplankton are getting simmered, and that's the right condition to produce the oil. Then if that is up near the surface of the earth, you're on Earth. If it flows out at the surface, then a couple of
things happen. One is it can devolatilize, and so that will release the stuff that kind of keeps it low viscosity, and it tends to get more gooey and sticky and tar like at that point, and ultimately the high levels of oxygen in ER's atmosphere will react with those leaking petroleum deposits on the surface, and ultimately, you know, they will release their energy through reaction with oxygen, but in a way that's not conducive to humans capturing that energy
and putting it to work. So there are places where that occurs, and you you know probably have heard of the LaBrea tar pits or the beaches at Carbon Drhea in California. Those are places where petroleum is actively leaking out onto Earth's surface naturally, all right, But in order to utilize oil, what we do is we try and find places where that hasn't occurred, but where it has
pooled in the subsurface. So, Daniel, if you thought it was complicated before, there's actually another step, which is that we need to take the oil out of these nice, warm source rocks and then move it into some place where it will pull in an accessible sort of setting. And so you know, ideally that would be some sort of subterranean trap. We call them, and one of the most common ones is a fold in the rock layers that goes up in the middle. It's so called anticline.
And if you have a sort of sandwich of less permeable and more permeable and less permeable rock layers such as shale sandstone shale. Then that provides a nice little and then you fold it into like a rainbow shape. The sandstone can soak up lots boil and natural gas, and the shale basically keeps it from leaving that arch. So, because oil is less dense than water, it rises to the top of the arch, but then it can't rise
any higher. The overlying shale acts as like a ceiling and keeps it from escaping.
This is like a geological Rube Goldberg machine.
Yeah, man, it is. And so people have tried to shortcut this, you know in some places where they've you know, said like, hey, we've got these tarsands up in northern Alberta. They're full of petroleum, but it hasn't yet escaped the source rock. But we can make it escape by grinding up those things and then boiling them essentially, and then we can let the oil out and then we can
burn the oil. But that takes a lot more energy investment, and so that really only becomes viable economically if oil prices are really high, like higher than one hundred and fifty dollars a parel.
So I bet they'd really like to have oil on Mars though, And if you're already spending all that money to get to Mars, maybe you're willing to spend as much as it takes to get the oil out. Is it in difficult places or does Mars just not have the right conditions?
I mean, I think Mars does not have the right condition So if we think about the various things that are necessary, like, did Mars have oceans in the past, Yeah, maybe probably? Did those have life in them? That seems like it's a little less likely. Did Mars have a sufficiently active surface environment to bury sediments? You know, enough subsidence in these areas where you'd get organic sediments buried.
Mars certainly doesn't have plate tectonics, which is what crumples those sedimentary layers up into those folds that concentrate the oil. But maybe there would be some other equivalent trap on Mars. It does seem like though each of these things is far less likely on a planet like Mars than it is on a planet like Earth.
How likely do you think it is? In general? We took a random planet and I said, there are oceans and there was microbial life. What are the chances that it has oil on it? Are we talking like one in two one in two million?
Insufficient data, Daniel, insufficient data. So we do not know that the parameters of these different exoplanets. But like one of the things that's necessary here on Earth to bury the phytoplankton in their little graveyard at the bottom of the sea is you need to have something to bury them with, right, so you need to have sediments. Well
where are those sediments coming from. They're coming from terrestrial and again I mean land source areas here where rocks are being weathered and they're shedding off particles big and small. But if you have a planet that's completely aqueous, where it's it's got no land, then what is going to bury those things in the first place? There's no source for sediments other than like chemical precipitates from the ocean itself. So there's no way I could put a number on
how likely it would be. I appreciate the question, it's worth articulating, but I cannot answer that.
We have focused on single cell organisms because we got this great question that focused on single celled organisms on Earth. Is all of our oil from algae or is it also from like dinosaurs and stuff, because that would be cooler.
Okay, so it's not from dinosaurs and stuff. So dinosaurs and stuff are terrestrial organisms. They live on the land, they wander around on the land. When they die, they're very unlikely to be preserved in the fossil record. You know, we are very attracted to dinosaurs, we go to museums to see their fossil remains. But the reality is that they are far, far, far far less common than marine organisms,
particularly marine invertebrates. So the fossil record is strongly biased towards things that live in the ocean, things that don't have backbones, things that lived a long time ago, like during the Paleozoic, Dinosaurs, you know, were limited to a relatively brief window of geologic time. And also the fossil record is biased towards things that have hard parts, such
as bones or shells or teeth. Dinosaurs do have bones, of course, but you know, three of those four are kind of stocked against dinosaurs basically entering the fossil record in the first place. Usually when a dinosaur dies, it's flesh rots away because it's out here in the open atmosphere where there's lots of oxygen that wants to react with all the carbon in its body. And that's if
it doesn't get eaten or scavenge. Right, So what we really want is circumstances where you know a dinosaur, maybe you know, dyed, bloated with gas, a flood washed it out to sea, then out at sea it popped, and then its skeleton and its remains could join the oil forming process. But that is really unlikely because that's not
its natural habitat. No, it's not dinosaurs. But basically it's anything organic that could enter these low oxygen settings where sediments will then bury them and they'll get warmed up to the right temperature. Let me maybe at this point invoke an organism that you may have heard of or may not have, the conodont. Do you guys know what connodants are?
No?
Okay, So for a very long time, geologists are trying to figure out how old sedimentary layers are, and we figured out that the fossils in those sedimentary layers change through time. So for instance, you find dinosaurs in some layers, you find trilobites in other layers, you find woldy mammoths in other layers still, right, So there is a time progression to the geologic record where the fossils change in a regular and predictable way. This is awesome on many levels.
It's a record of past biological evolution on our planet. But it also is kind of a tool for figuring out how old the sedimentary layers are, and when coupled with other tools such as isotopic dating, say, have a granite dike that cuts across a trilobyte bearing shale. You can then figure out, by dating the dike how old the shale must be. The shale must be older than
this igneous rock that cuts across it. So we've been using this principle of relative dating by fossil succession for centuries now to figure out how old sedimentary rocks are. Leonardo da Vinci even practice this all right. So these fossils are most useful when they are distinct and recognizable, when they're very cosmopolitan and widespread all over the planet, not limited to some particular habitat or land mass or island or whatever, And when they are limited to a
brief period of geologic time. So those three characteristics make for a good index fossil. Cockroaches are lousy index fossils because they've been around for hundreds of millions of years. So you find a rock with the cockroach in no big deal. It doesn't really tell you that much. But connidants are powerful index fossils. So they are these little things shaped kind of like teeth or spike balls, or they look like sort of sadistic ice skates or something
like that. They are made out of a mineral complex called hydroxyl appetite, and they're found in sedimentary rocks the world over from the Cambrian period of geologic time up through the Triassic or Jurassic. Sometime in the Middle mesozo and people were like, hey, these things are awesome. You can really use them to tell these rocks apart. But
they're different ages. We had no idea what they were, right, So they were just these things that we could find, these entities, and we were like, Okay, they're useful, but
we don't know what they are. And recently they found out that they're part of the head region of an eel like critter, so a very small, little thin fish where the other parts of its skeleton are not hard enough to enter the fossil record, but they found one of these rare fossil occurrences where we've got the soft tissues preserved, the muscle blocks and some of the skin,
the eyeballs. They've got great big eyes, so they look to be like sort of gill support structures or something related to the mouth, but not traditional teeth like you or I have. And these things are really neat because they can not only tell us time, but they change color when they get different temperatures. So a geologists at the United States Geological Survey, Anita Epstein, figured out that you could use the color of Kanada to figure out if the rocks had gotten to the right temperature to
generate oil. So they would basically go from sort of a yellow color to an orange to a burnt umber kind of orange brown to a gray brown to black, and you could figure out exactly the temperature that they were cooked at, and that could tell you whether the rocks at that depth got to be the right temperature for oil production. A pretty neat trick. They call it the connidant alteration index. And there's a nice little article on Wikipedia you can read if you're interested in exploring that.
More So, when people are like trying to figure out where oil is. If they find one of these things and it's the right color, are they like, Okay, now we need to dig in this area a lot more. And that's like an indicator that you're in the right spot.
Yes, and if it's the wrong color, don't bother.
Okay, and mars, we'll have none of this. So we're we're out of luck there. But that's awesome.
My last question is do all these names they give to soils and rocks maneuver? Do these actually make sense? Or is it a big pile of nonsense the way it is in astronomy, with arbitrary dotted lines that date back to like some old man in robes in seventeen hundreds who gave something the wrong name.
I mean, I'd love to tell you that it all makes perfect sense, but you know, like the English language, the geological lexicon has adopted words from other traditions, other languages. I really like thinking about the origins of these different words. I think kana dant. I'm sure that breaks down into something like cone shaped tooth in terms of its etymology. But geology is very rich with words from French, Italian, Scottish,
even Indonesian Bahasa. Indonesia has contributed major words to the geological lexicon, and I love that sort of melting pot aspect of the science. It's very appropriate for the Indonesians to have a word for a volcanic mudflow, a lahar, but you wouldn't expect that to originate from Scotland. But it's very appropriate for the Scots to come up with
words like esker and turn, which described glacial features. So it tells you something sort of almost anthropological about the place where these words originate.
There's like sentiments of words that build up over time.
That's a good way of thinking of it. And probably some of these words are almost like index fossils, right where they come into fashion for a while, they're used, and then you can only find them in the deepest, dustiest pages of the literature, which is.
Where we love to explore. All right, well, thank you so much, Callen. This was super helpful, and we're going to send your answer to Ust and he'll tell you if he feels like his question was answered right on.
Okay, good luck, everybody.
I love talking to geologists. They rock.
I bet Callen has never heard that.
Sure, Hi, Kellen, Daniel and Kelly, thank you for those rock solid answers. I'll put my plans for a oil company on Mars on a hold.
Now, thank you.
All right, Well, I am so glad that youst felt like he got his question answered. And so now let's take a break and we'll move on to a question from Scott, who unfortunately is from California. We don't all get to pick where we're from.
All right, we're back and we're answering questions from listeners like you. If you have a question about the universe that nobody you know can answer, send it to us. We will answer it for you. We write back to everybody. Send us an email to questions at Danielankelly dot org.
Well try to get you an answer. Not all questions have answers, but we will do our best. But I guess there's no answer is also a kind of answer.
Mm hmm. Yeah. The answer nobody knows is unfortunately the answer to most questions. And today we have a thorny question from Scott from California. He's asking about a famous physics experiment. It leads to all sorts of tricky philosophical wrinkles.
This is Scott from California. I have a question about the double slit experiment. I am imagining a probability wave of a particle approaching the first barrier that has the slits in it. As the wave approaches that first barrier, I'm assuming that the universe has to make a decision about whether the particle is going to hit the barrier
or go through a slit. That is, the wave function would collapse, and the particle would find itself hitting somewhere on the barrier, or perhaps find itself right where a slit is. If it finds itself right where a slit is, does the wave function then instantly uncollapse such that it goes through bow slits simultaneously. This question has been bothering me for a long time, so I'm really looking forward to getting an answer. Thank you so much, oh Man Scott. That is a great question.
And I have vague memories of the double slit experiment from freshman year of college, but I guess that's twenty years ago now. Oh my gosh, So Daniel, well refresh my aging memory. What's the double slit experiment?
Yeah, I think it's useful to nail down exactly what we're talking about. So we can figure out how best to answer Scott's question. This is a famous experiment that's been done in many ways, with changing interpretations over time. So the first version of this experiment was done with light. You have some source of light, a light bulb or a laser or whatever, and you shine it on some barrier and most of the light is absorbed, but you have two little slits in the barrier, and where those
slits are the light can go through. So now on the other side of the barrier you have these two little narrow slits which act like sources of light themselves, right, almost like you have two little light bulbs right there. And then the light that comes from these slits hits some screen, and that's where you're observing it. You see on the screen, it's not just like light from the two slits. You see an interference pattern. You see that in some places it's dark even though the light hits it,
and other places it's very bright. And that's explained by light being a wave and canceling out in some places and adding up in other places. So the first earliest version of this experiment showed us that light had these wave like properties because it interfered with itself on the screen.
Okay, I'm following that, but I feel like I also have a vague memory of physicists talking about light as a particle. Yeah, what's going on there?
So now it gets weird. Remember, the crucial explanation for why do we have interference is that we have light coming from both slits, right, Each one is like a little source, and sometimes their waves go up and the other one is going down, and sometimes they're both going up, so they add up. But the crucial thing is you have two sources, which is why you have interference. So then slow the experiment down. Now we know light is actually made out of little packets. It's not like a
continuous stream. Right when you turn on your flashlight, it's actually shooting out little packets of light, these things we call photons. And so you can make this experiment more interesting by slowing it down and saying, what happens if we only have one photon in the experiment at a time, right, instead of huge numbers of photons which you're interfering with each other, what happens you have a single photon and then you see something very strange, which is the interference pattern.
Builds up gradually on the screen. So one photon comes through and it lands in one spot, another photon goes through it lands in a different spot, and then the third one in another spot. But if you do a million of these, it adds up to give you the same pattern you saw when you illuminated it with a
huge amount of photons all at the same time. So the confusing thing there is, and I can see Kelly's faces going hot, is what's doing the interfering Because in the earlier version I explained that the interference pattern is coming from having two sources. But if the one photon is in the experiment at a time, what is it interfering with? That's the big puzzle.
Is the answer going to be quantum entanglement or something? Why do you all always make this so complicated?
The answer is definitely quantum mechanical, though not entanglement. What's happening here is that the photon is not like a little particle that has a specific path and it goes through this slit and then hits the screen. The photon has a probability to go through one slit or the other slit, or to get absorbed by the barrier. Right, we don't know where an individual photon is going to go, and it's that uncertainty, that probability that's doing the interfering.
So remember that picture I painted in your mind of light going through the experiment and coming out of the slits as little sources and then interfering with itself. You can use that exact same picture, except instead of thinking about it in terms of light, think about it in terms of probability for one photon. So you send that photon against the barrier, it has a probability to hit
one slit or the other slit. That probability passes through both slits, right, And then that probability interferes with itself and creates a probability distribution on the screen in the back. Then the universe has to pick, Okay, where is this photon actually going to go? So I can put it somewhere on the screen, and it draws from that probability distribution, and it puts one photon, So that probability distribution guides
each individual photon. It puts more where the probability is U is high, in other words, where the interference pattern is bright, and fewer where it's dark, So that it gradually it builds up the same interference pattern you saw when you shown the light brightly. So you just replace the concept of light waves with probability waves and all the same math works.
Awesome. I think I had been imagining when we were sending a particle through the slits that we had directed it to one slit in particular, not that it could have gone through both. But it's not like I had the probability stuff in my head. So I still, yeah, anyway makes sense now, awesome.
Yeah, it's crucial that you don't know in advance which slid it goes through, that you have the possibility for it to go through both slits, because then the other version of this experiment is, well, what if we check. What if we put a little detector like a camera or something that can tell whether the photon went through slit A or slit B. Then what happens, Well, then the universe picks witch slid it went through because you
put a detector there, So you've collapsed the probability. Instead of allowing for the possibility that the photon goes through either slit, you now force the universe to pick which
slid it goes through. So then the inner feference pattern disappears, and you just get photons going through one slit or the other slit, and you get a geometric shadow instead of an interference pattern because there isn't probability coming out both slits because you force the universe to pick and now it just sends a photon to one slit or the other slit. This is this bizarre process we don't fully understand of how possibility becomes reality when the quantum meets the classical.
It still absolutely blows my mind that just measuring it changes the pattern that you get on the back wall, Like is it just shy? And like you know, what is the leading theory for why observing it changes things.
It's not something we understand very well. And this is called the measurement problem in philosophy of physics. It's really a puzzle. I mean, we have this quantum theory that says things of the quantum level follow these equations of probability, and that's the Shirtinger equation, and they can have weird properties like not having a specific location but instead having a probability to have several locations, or having ability to
be spin up or spin down. You can maintain a superposition of different possible outcomes, different possible properties for yourself. That's what quantum objects can do. But we know that classical objects can't. Like when you have a screen, the photo either hits here or there. It doesn't like half hit here and half hit there. Or when you flip a coin, it's either heads or tails. It's not like
half heads and half tails. So we have these two different worlds, the quantum world where you can have superpositions, and the classical world where you can't, and we don't really understand the transition between them. It's confusing because everything in the classical world, like quarters and me and you, are made up of quantum things. So the leading theory
is sort of nonsensical. The leading theory, called the Copenhagen interpretation, says that all right, you have quantum stuff, and it can have multiple possibilities, and it can do all sorts of crazy wavel like things like interfere with itself and
its own probability. But then when you interact with a classical object like an eyeball or a detector or a screen, then the wave function collapses and the universe to pick says, instead of this whole spectrum of possibilities, you just pick one, and that allows us to have classical outcomes like hey, it's up or it's down, the photon is here, photon is there. This collapse theory doesn't really work because number one, it violates like basic quantum mechanical rules like quantum information
is never lost. And also it's not really well defined. Like when I said a quantum object meets a classical object, I wasn't clear on, well, what is a classical object exactly, because as I said earlier, all classical objects are made to quantum objects, and that's the puzzle. Nobody can define the barrier between quantum and classical objects, so we don't really understand it. We don't have a great explanation. It's one of the biggest open questions in philosophy of physics.
Still so much left to do, still so much leve to do, exactly. So let's get to Scott's question. And Scott is thinking about what happens when the photon is approaching that barrier, and I think that he's imagining that either the photon hits the barrier and is absorbed, or hits one of the slits and goes through and I think Scott is thinking that maybe the universe collapses it at that moment when it either hits the barrier or goes through a slit, because it sort of encountered some
big classical object, and then he's confused about how later we can say it maybe went through both slits and is there some uncollapse, Like how do you get multiple possibilities through that barrier? I think is essentially Scott's question, And the answer is that hitting that first barrier doesn't collapse the wave function because you've still left multiple possibilities. It can go through slit one or go through slit two,
so both those possibilities propergly forward. So the short answer is the first barrier doesn't collapse the wave function unless you have a detector there that's saying like, hey, did
you go through slit one or slit two? Because you allow the possibility of multiple slits, you allow the quantum mechanical properties to maintain and for there to be a superposition of two possible outcomes, and so then both of those possibilities go through the slits, and then you get the interference from those two two possibilities.
So if it collapses at the two slits. Instead, you get a totally different answer.
Yeah, if you collapse it at the two slits, which you can do if you put a little detector there and you say, I want to know which one it went through, then you get a totally different answer exactly, you get a different pattern on the screen. And crucially, you can't uncollapse Like when you collapse the wave function, you go from here a whole bunch of possible outcomes to now there's just one, and you can't ever uncollapse it.
You've lost information, which is why it's so confusing. And we've said on the podcast before, like you can't lose quantum information. It can't be deleted from the universe. But this collapse theory does violate that principle of quantum mechanics, and people out there might be like, hold on, aren't
you contradicting yourself? Yeah. Absolutely, And this is one reason why we haven't really figured this problem out, like we have this best explanation we have violates other things we know about the universe, so it's like a work in progress.
Yeah, this is one of the really fun things I think about podcasting with a physicists. I hadn't realized there were so many works in progress, but it's exciting that there's so much left to discover. So I feel like I understood that. But let's go ahead and test ourselves and ask Scott if did we actually answer the question that you were asking, and if so, was the answer clear that's right?
Or did we just collapse his brain? Okay, So it's my pleasure to welcome to the podcast, Scott Goldman. Scott, thanks so much for running in with your really fun question.
Yes, thank you.
So tell me you heard me and Kelly talk about the double slit experiment and what happens to the wavefront as it hits the first barrier and interferes afterwards. Tell me does that make sense to you? What questions do you have or meaning?
So it makes sense to me, I guess it all comes down to one question, and that is, every time a particle is shot at that double slit, the barrier with the double slit, and there's a probability wave that comes to that barrier, it goes through both slits, interferes with itself, and when it gets to that detector screen the universe at that point then I guess has to
make a decision where it hits. My question is does every particle that is shot at that barrier with the double slits go through and then hit the detector screen or do some particles not hit the detector screen because they actually hit the barrier somewhere instead of going through the two slits.
Yeah, great question. The answer is the second one. Not every particle makes it through butt, and there's always a butt. Every particle has a probability of making it through, so there's sort of a lot of different outcomes. One outcome is you make it through one of the slits and you end up somewhere on the screen as a dot. Another possible outcome is you don't make it through at all. So imagine that probability wave approaches the first barrier, or
the one with the slits in it. Some of the probability wave makes it through and interferes with itself and gives it a probability to hit the back screen, but a lot of it, as you say, hits the barrier. So then when you force the universe to roll the dice and say what is the outcome for this particular particle, A lot of them are going to hit the barrier, and most of the descriptions of this experiment. They sort
of ignore that part because that's not so interesting. We pay attention mostly to the ones that go through because those are the ones that do the interfering. But yeah, a lot of them. If you ask, like, hey, what happened to this particular particle, you'd ance it would be that a lot of them hit the barrier and don't make it through.
Okay, So that's the part I guess where I'm having trouble understanding because I'm imagining this probability wave approaching the barrier, and then when it gets to the barrier with the slits, the universe has to decide like, oh am I going to hit the barrier, or no, I didn't hit the barrier. I happen to I'm gonna be right in this little space where there's a slit. But then it goes through both slits.
Right, yeah, So the universe doesn't necessarily have to decide there, right. What it can do is have several possible outcomes. The wave approaches the barrier, and now there are three possible outcomes. You go through one slit, you go through the other slit, or you reflect or maybe get absorbed, depending on the nature of the barrier. So the probability is sort of fragment there. But they don't have to collapse, right, They
only collapse when you insist, you know. But if you don't insist, you know, you're like, well, I'm just going to allow the universe to keep doing its thing. Keep that within a black box or keep my eyes closed for that part of it, equivalent. Then it can continue to propagate all three possibilities that it reflects back, or that it goes through one slit, or that it goes
through the second slit. It can maintain all of those, and it's maintaining the uncertainty that allows it to make that interference pattern.
So some of the probabilities go through the slit, and then when it gets the detector screen, at that point it decides whether it actually made it through or hit the barrier.
Mm hmmm, yeah, exactly. It doesn't have to collapse when it hits the barrier.
Oh gosh, sorry.
Yeah, no, that's yeah, it's amazing. It's sort of crazy. But the way to think about it is that it's allowing some of that probability. You can also think of it another way. You can think, you know that the probability, most of it gets zeroed out and only those two little narrow slits of probability remain. But there's still uncertainty there. You don't know which way, and so that's what allows for the interference. And I think a lot of people
are confused by that. They're like, well, why doesn't the barrier collapse the wave function?
Right right?
And you can think about it that way also, and you can, for example, add detectors to the barrier so that the only possibilities for the particle are that it goes through a slit or it hits the detector, and that doesn't collapse the wave function completely. That just says, if it hits the barrier, then I want to know. If it doesn't hit the barrier, there's still uncertainty because they could still go through either slit and then you'll
still get the interference pattern. So that scenario you could sort of partially collapse the wave function. You'd be like, if it hits the barrier, I want to know. Otherwise I'm going to allow for the uncertainty to propagate through both slits. So this is an infinite number of confusing and amazing ways to do this experiment. All right, well, I hope that helped you understand. Thanks so much for asking the question.
Thank you, and we're back.
Our final question of the day is a question from Lewis on Discord, and here is his question.
Hi, Daniel Kelly, I was wondering what kind of adaptations might we make to humankind, whether genetic or bionic or anything, to help us to live on a place like Mars. Thanks, looking forward to hearing your answer.
All right, Oh my gosh, there's so many problems on Mars? Which ones should we try to solve?
I'm excited that you're optimistic about this. I thought your answer might be like, it's impossible to give up.
I mean, the back of my mind is saying that, but I'm gonna let's try to have some fun. Let's start with the problems that could kill us. And so those problems are probably radiation, partial gravity, and depressurization. So I think those are the top three. What do you think, Daniel? Are those the top three worst problems on Mars?
Those sound pretty bad, yeah, and I think I'd love to hear solutions to those. And this is great because it gives you an opportunity to demonstrate your optimistic side instead of just throwing cold water on humanity's prospects.
Oh man, I hope that doesn't mean this is going to be a bad answer, because it's not in my skill set to be optimistic.
Okay, let's see, all right, let's hold.
Off on the depressurization problem till the end because the initial set of solutions that I have are not really good for depressurization. So one problem is radiation. So, as we've discussed on a couple other episodes, space has different kinds of radiation then we typically encounter on Earth. So you have solar flares and solar part of events, and these are like shooting protons.
Boo boo, boo boo.
You can dive right away from something like radiation sickness just shuts a bunch of your organs down all at once, or you can get cancer which will kill you slowly. Also, we have galactic cosmic radiation, not one hundred percent sure where it comes from. Could be from exploding stars in black holes, but we don't really know, right.
Daniel, Yeah, exactly, Yeah.
All right, So the galactic cosmic radiation tends to be bigger, like charged ion particles. I saw this one paper it was an old paper from like the seventies, but they got a gel that was meant to be sort of like the human body, and they shot an iron ion through it and it blew a hole the size of a human hair, which like, does I mean usually like, oh, size of a human hair that's used to indicate something small, but like, I don't want holes the size of a
human hair in my brain. Like that's no good, no.
And that's a great image because it reinforces the message that these things are not like little fuzzy quantum objects that somehow interfere with you. They are basically space bullets. Right, Space is shooting at you, and we have a bulletproof vest here on Earth. Right our atmosphere is protecting us. It's absorbing all that kinetic energy and we're lucky. And so yeah, how do we deal with life on Mars without our atmospheric bulletproof vest Kelly?
The easiest solution is probably something related to shielding. But radiation, well, space makes everything complicated. But one way radiation is complicated is because of something called spellation. So when galactic cosmic radiation hits your habitat, it hits particles that it then breaks into other kinds of particles that are also radioactive and now rain down on you and what's called a nuclear shower. See, Daniel, you asked me for a solution,
and I'm giving you reasons why it's worse. My pessimism is winning, all right, I'm backing up.
Okay, So you're saying, if I walk around Mars with like an umbrella of some very heavy duty material to protect myself from radiation, it's actually just going to generate like showers of radiation underneath.
The umbrella, depending on what the umbrella is made out of. Yes, so there are some particles that are better at absorbing things. I don't think anything's really great at absorbing galactic cosmic radia without breaking up. But could bury your habitat in regolith, which we've talked about before. But you know, human bodies can repair some damage, and some of us are better repairing damage than others. And so let's assume that part of the solution is you're burying your habitat and regolith.
But you could also specifically send two Mars people from Earth who are more radiation resistant, and to be honest, I don't know how we pick those people yet. Because like, we don't have a lot of experience with space radiation, but presumably there's variation in this trait. So you could send more radiation resistant people up to space, and at least for the first generation, that might help maybe.
Because they are like less likely to get cancer. They have some sort of like genetic predisposition, Like biologically, how does that work? What is it about some people that makes them like more rad proof than others?
No, great question? Who knows, right, Here's Kelly, We don't really, you know, And so that there are some people who are like, well, you know, we can pick people who are more radiation resistant, and then we could figure out what it is about them that makes them more radiation resistant, and then we could try to use genetic engineering to tinker to make the next generation more radiation resistant, and like, through this combination of crew selection and genetic engineering, we
can create people who can survive better in space. Here's a tiny little bit of pessimism. Really quick, I won't linger too long. But you know, most of the important human traits are not controlled by like a gene that you can tinker with. So like our genetic engineering of humans that has gone best so far has involved tinkering with genes that don't get past to babies and dealing with diseases that are caused by like a mutation in one spot. So if radiation is controlled by one hundred genes,
you could tinker with all those genes. But the other problem is that genes usually don't just do one thing, so when you tinker with all those one hundred genes, you might be messing up other stuff too. So actually, let's go ahead and say that's not the best solution. And now, because I have a physicist on the show and an optimist, maybe I'm going to kick to you.
So let's imagine that we are living in an environment where we have where money is no problem, and we have as many nuclear portable nuclear power plants as we could possibly need. Could you use electricity in some way to protect your habitat from space radiation? I know it's energetically expensive, but like, could we super coil?
Like?
Are what are our solutions here?
Yeah? Well, these things are mostly ions, right, and so these they are charge particles, and those charge particles can be repelled or redirected by electric fields, but they're very, very high energy. The good thing is that the very high energy ones are rarer, so while it'd be much more challenging to redirect the high energy ones, there are less common. The rate falls very very quickly with energy. But yeah, it would cost a huge amount of energy.
I mean, really, the better way to do it is a magnet, right, rather than relying on their electric field, because that's what the Earth does. The Earth has a magnetic field, and we deflect a lot of this stuff. There actually is a fun proposal to put a huge magnet between the Sun and Mars to create like a
magnetic shadow for Mars to deflect these particles. And I asked a friend of mine who's a planetary scientist who has actually worked on like Mars missions, and he says, quote, this is literally the dumbest idea I have ever heard. I almost fell out of my chair when I saw someone presenting it.
Okay, I feel like pestimist, I know.
And I asked him to elaborate, and he says, quote, there are so many reasons it's stupid. You have to somehow make a giant magnet. You'd have to put it on a ginormous spaceship and keep it in orbit around the lagarage point, and It goes on to point out that not all of the radiation comes directly from the Sun, so the shadow wouldn't even protect you. And a lot of the radiation are UV photons, which do not have a charge and will not be deflected by magnets or
electric fields. You really need the combination of a magnetic field for your whole planet, not just a shadow, and you need an atmosphere to absorb the stuff that isn't charged. So yeah, physics doesn't have an answer for this one either.
Oh man, okay, well, let's move on to the next problem. I don't have an answer really, And then of course there's all the ethical things that we just completely glanced over with genetic engineering, so that that is something else holding this all back, all right, So then the second problem is partial gravity. So Mars has forty percent of
the gravity we find on Earth. We know that astronauts who experience no gravity when they're in free fall lose muscle mass, bone density, and that might explain why they start losing some of their vision or some of them, not all of them. Because the fluids, you know, we're adapted to have gravity pulling our fluids back down. So when we don't have that benefit. Fluids tend to go up and they like push on our brain and they might be changing the shape of our eyes. So forty
percent gravity would that solve the problem. We don't know. Like some of those problems maybe bones and muscles, for example, that could possibly be solved by like putting on really heavy weighted outfits that sort of make it so that you're carrying around as much weight as you'd be carrying around on Earth. That might help keep everything nice and strong.
I don't know if that's going to help with like fluid related problems or like anything else in your body that's associated with partial gravity, but you could, and I've seen proposals for this, create banked race tracks to create artificial gravity, and you could, I don't know, maybe sleep
in those and that might be enough. And then I also have seen proposals for what are called sucky pants or sucky sleeping bags, and they they create a different kind of pressure and it pulls the fluids down, and so you could like sleep in these or wear these. They're like you have to tune them well because sometimes when they turn them on like too fast or too strong, the fluids rush out of your brain and people like pass out, which is not great and they don't look
super comfy. But so there are some technological solutions.
But to be clear, here you saying that we know there are problems in zero gravity, and now we're asking like is forty percent gravity enough? Like do we still have those problems in forty percent? And then what can we do about solving that additional bit? Right?
Yeah? Right, So I am assuming that forty percent is not going to solve all of our problems. If it does, then great, we don't need any extra help. If we do need extra help, here are some things we could do.
But who wants to live on like a banked racetrack their whole life? That doesn't sound like a fun place to hang out. Or maybe only part of the time you need to be on the racetrack.
Yeah, we don't know. Maybe you could sleep on the racetrack and that would be enough, but I we don't know.
Well, what about something like more inherent? Is there something we can do inside the body, you know, like to modify the structure of our bones or chain some fundamental process inside of us that'll just make us more naturally suited to that kind of environment. I'm thinking like really science fiction craziness here.
I had fiction craziness. Okay, so right, So one of the questions would be, like, does our current genetic make up include enough variability where we could tinker with things in the right way to make us survive better in these environments? And so you know, maybe there are, for starters, people who have bones that are thicker than thicker than others and would maybe do better in an environment like this.
And if we can figure out why they have thicker bones, maybe we could tinker with the DNA of future generations, which is a phrase that makes me shudder just thinking about it. But anyway, we could do that maybe and like thicken up their bones so that maybe it wouldn't matter if they're in an environment where you would expect bones to atrophy because they were already stronger to begin with. Like maybe that'll be enough. I really don't know. For this one. I kind of come up at a loss
with radiation. I felt like it was maybe a little easier to imagine.
Well, my question is like who's working on this stuff? Like can you do any kind of ethical research here in terms of like bioengineering humans or are people doing like bioengineering on rats and dogs and stuff, or just sort of theoretical. Is it possible to do research in this area.
So with new Crisper technology, it's easier for us to tinker with genetic information, so to like cut bits out and replace it with other bits that we want, And we have used that to help out with some diseases, so for example, sickle cell anemia. By tinkering with some genes using Crisper CAST nine, we've been able to like make people's lives way better. So we are getting better at using some of these techniques in humans, which is a big step, I think, And so we're getting a
little outside of my expertise. I think. The first time that technique was used on babies in a way that it would be transmitted across generations was done in China, and they got thrown in jail for that because the whole international community was like no, no, no, no, no. We were not okay. None of us are okay with this. You jumped way too far ahead. And so I think that research is gonna not move forward, I hope for a while.
And if I could press on that for a moment, like I've always wondered, is there a crisp understanding of why it's okay to breed humans by selecting your mate but not by editing their genome is the only answer just like, well, this is a dull enough strategy that you can't like feel too bad if you mess up and you know your kid doesn't have the genetics you want it, or something like is it just the power of this technology to create horrendous outcomes?
I think it's a couple things. So one thing is that we as a species have a lot of experience with mating and having babies and seeing how that turns out. But when you start tinkering with things at the genetic level, things don't always go the way you think they're going to. You know, you think you understand a system, you tinker with it, and maybe that child will have catastrophic issues they'll have to deal with for their whole life because you decided to tinker with their DNA, but just.
To play devil's advocate. The same thing can happen when you choose your mate, Like, for example, if you're in a small community and you choose to select your partner inside your community, you open them up to possible conditions that come from genetic populations, you know, like I'm an Ashkenazi Jew. I know that tasax syndrome would have been a real risk if my partner was also an Ashkenazi Jew.
Yeah, And so I don't think Zach would mind me admitting that he's a carrier and that I had to get that test because that was a real risk for us. But I think that is why we try to have genetic testing, so that you can be aware of these potential issues and make decisions based on that to avoid
these worst case scenarios. And so I think we would say we don't want to stop people from marrying and having children with the people that they love, but we do whatever we can to minimize the negative impacts of that. I think trying to improve a bad situation you find yourself in is very different than trying to tinker to
get something better that you would ideally have. And so, and I think that leads to the second problem with genetic engineering is that there's this concern that people who can afford to tinker with their kids are going to end up having like what often gets called in the press as like designer babies, and that we're going to further see inequality sort of exacerbated by this kind of thing.
Right, Like I want my kid to be a long jump champion, so I'm going to give them this genetic package, which costs a million dollars or whatever. Yeah, that does seem like terrifying. I'm already terrified to make any sort of decisions from my kids, like oh, we're going to this high school or that high school, or you have to eat this way or that way, and I wonder that by the consequences for the rest of their lives. So yeah, I'm glad to not have to have made some genetic decisions.
Yeah, well, and we should have, like you know, maybe maybe one day we'll have a bioethicist on the show to talk about this stuff, because it's complicated and I feel like the more you think about it, the more you're like, oh, but it would be great if we could do that. But it would be catastrophic if we could do that. And like, you know, there are people who spend their whole lives thinking about this much and much more detail than I did.
Yeah, and the technology will be available eventually and then we're going to figure out what to do about that. But yes, let's have an expert on who actually knows this stuff.
So, staying on genetic engineering for a second, there are folks who argue that we need to start doing this kind of engineering now because it's really important that we start having self sustaining settlements on Mars as soon as we can, because we never know when something catastrophic could happen to the Earth, and it seems like a lot of catastrophic things are happening lately. So it's important that as soon as we can we get people living on
Mars in a way that can happen sustainably. And so maybe that should make all of our ethical concerns, those concerns should be dwarfed compared to the importance of keeping the human species going. I don't personally buy that argument, but you know, there are these emerging debates about the ethics of doing it, and how those ethics sort of change if we think that this is something we need to be doing quickly for the safety of our species.
Wow, it's so hard to imagine what the future of humanity holds. It can go in so many different directions.
And because I'm a pessimist, I will go ahead and note the one final way you can get humans that are well adapted to the Martian surface, which is natural selection, which every once in a while you'll see noted in the literature as like, oh, well, you know, after enough generations have people who are well adapted to the Martian surface, And of course that means many, many people will die and root, and it's not even one hundred percent certain
that we have the right kind of genetic variability where eventually there will be people who can survive you know, radiation on Mars are living in forty percent gravity, and so we might just lose a bunch of people, which sounds really awful.
Also, don't you assume that you start from a pretty large population, Like if you start from ten people, it's unlikely you're randomly going to have the right genetic mutation. You need to start from a pretty big population, right, which means a lot of people are going to die, like big numbers.
Wow. Agreed, Yes, you know, But you know Musk would argue with Starship he can get a million people there in thirty years, and he can, you know, keep sending people. I should clarify, Musk is not the one who has said we're going to let natural selection solve the problem. He hasn't been clear on how this problem's going to
get solved. Free market somehow, free market something something. The next thing we're going to talk about wouldn't solve the partial gravity problem, but would solve problems related to radiation to some extent, and depressurization. So the problem with depressurization is that when human bodies go from an area of higher pressure to an area of lower pressure, the nitrogen bubbles out of our blood, and if it gets stuck in your joints, it causes the bends because it hurts
so much that you bend over in pain. If those bubbles get stuck in your lungs, you get the chokes, it's hard to breathe. If they get stuck in your nervous system, you get the staggers, You get these nervous system problems. But if it happens to you in space, you're just going to get the death, which unfortunately is what happened to the crew of Solute one they got
exposed to the vacuum of space in the seventies. So, how do we make a Martian atmosphere thick enough, with enough pressure so that you could go outside without a spacesuit and you wouldn't have to worry about your habitat depressurizing, and Daniel, I think the only solution to that would
be terraforming. Could you thicken up the atmosphere and the pressure enough by the proposals that I saw involved like sending nuclear weapons to the poles so that you could blow up the ice there, and that that ice would then distribute itself in the atmosphere and would thicken up the atmosphere, and that might even warm up the planets. Could that solve the atmosphere thickness problem and radiation or we just noking a planet for no reason.
It's not an easy answer. Like Mars is like one percent of the Earth's atmosphere, so you'd need to increase the atmospheric pressure by a lot. And there definitely is CO two and the poles of Mars, and you could release some of it. But the problem is that if you release too much CO two then the atmosphere becomes poisonous to humans, and so it doesn't really solve the problem,
and you'd need a lot of CO two. You need to like scoop up some of it from Venus and transfer it over to Mars, So this is not an easy way to manufacture the kind of atmosphere you want. Ideally, you want a huge amount of oxygen in the atmosphere so you can walk around without a suit, But oxygen is hard to make. You know, you basically need some sort of like micro trubes growing on Mars eating this
theo too and producing oxygen. And my wife is a microbiologist, and she thinks that would take millions of years optimistically, And you know on Earth it took quite a long time. And the rocks are going to drink a lot of that oxygen before it even stays in the atmosphere. And we know that Mars is like likes to get rusty, and we don't know if you can gobble up more
of that oxygen. So terraforming is not an easy solution, which is why I think this question is actually asking for another kind of solution, like what can we do to change ourselves so we can walk around in that one percent, Like could we engineer some sort of crazy high pressure skin that's basically like a suit, or change something fundamental about a biochemistry so we could just happily walk around in one percent atmosphere.
Daniel nothing's coming to me. Do you have an answer? I mean, even if you had high pressure skin or like, what would high pressure skin be like, like you turn your skin to metal.
Basically, I just have a natural suit, you know, as part of your body. It's not really an answer. Basically you're wearing a suit, but it's part of who you are now, So technically it might be a solution.
But like, if you open your eyes or your mouth, aren't you exposing yeah, yourself to the pressure change? Like, I don't see this working.
Look, I only solve the problem for a minute. I don't know's to lunch?
You know, Well you got you know, incremental you gotta let the market something something exactly.
The first candidate survived until lunchtime and then they depressureize. So let you know, we take a break and come back and tell the rest of the problem another time. Yeah, I think the answer is that it's hard, right. Pressure is important, and we are just really not designed to
survive in a low pressure environment. You're right. We exchange all sorts of fluids and materials with the environment, and so sething ourselves off from it is not really a solution, and it's hard to imagine well, what if we somehow, like inflated humans, we lived in a low pressure environment. I'm imagining like a completely different kind of biological being, you know, where, like your insides are actually at lower pressure.
I can't imagine you'd be able to do that with current genetic variability that's like available, But I mean you could. I guess, like every generation you lower the pressure in the habitat, and whoever survives you work with that. But that would take a long time and would not be ethical.
No, not even close to ethical. No, absolutely not. All right, so it sounds like we're not going to be adapted to living on the surface of Mars very soon, and even our craziest technological solutions are not really well suited to the task.
I have to admit, I don't feel like we came up with any super satisfying answers. But let's go ahead and ask Lewis if he feels like we did the best we could.
I'm terrified what kind of grade we're going to get.
Thanks so much, Daniel and Kelly. I did not appreciate quite the cannon Williams. I was looking man, and I definitely get the message. I think I'm going to stick around on Earth for a little while longer.
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