DKEU Listener Questions Volume #3

Daniel and Kelly answer listener questions about soil on Mars, the double slit experiment, and adaptations for surviving on the Red Planet. 

See omnystudio.com/listener for privacy information.

Episode Transcript

Speaker 1 (00:06):
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

(00:27):
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

(00:48):
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

(01:09):
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.

Speaker 2 (01:32):
I'm Daniel, I'm the particle physicist, and I love getting
your questions.

Speaker 1 (01:36):
I'm Kelly Wienersmith. I study parasites, and as you already
know from the opening, I love getting your questions too.

Speaker 2 (01:43):
Do your kids ask you science questions you can't answer? Kelly?

Speaker 1 (01:47):
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,

(02:08):
which is such a bummer. But uh, is that.

Speaker 2 (02:10):
Because your answers are too long? Is that why?

Speaker 1 (02:12):
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?

Speaker 2 (02:19):
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.

Speaker 1 (02:30):
I mean, your dad's a college professor. That's what you're
going to get.

Speaker 2 (02:35):
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.

Speaker 1 (02:47):
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,

(03:09):
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.

Speaker 2 (03:22):
Hello, Daniel and Kelly.

Speaker 3 (03:24):
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

(03:46):
oil or do we need at least bigger life than that?
Thank you for the podcast, Kind to your guards.

Speaker 1 (03:53):
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?

Speaker 4 (04:13):
Hey, thanks for having me. I'm glad to be here.

Speaker 1 (04:16):
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

(04:37):
me what is the difference between soil and just dirt
and regolith.

Speaker 4 (04:41):
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.

Speaker 2 (04:55):
Be confused with the delicious dip with the heeny in it.

Speaker 4 (04:59):
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

(05:22):
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

(05:44):
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

(06:04):
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

(06:25):
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

(06:48):
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.

Speaker 2 (07:05):
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.

Speaker 4 (07:18):
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

(07:40):
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

(08:01):
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

(08:21):
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.

Speaker 1 (08:31):
So Mars has red soils like that. Is there any
similarity there or am I just reach in.

Speaker 4 (08:37):
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,

(08:58):
or whether it was underground due to ground water. You know,
there's a lot of possibilities there.

Speaker 2 (09:02):
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?

Speaker 4 (09:12):
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.

Speaker 2 (09:26):
Love that word marsquakes.

Speaker 4 (09:27):
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.

Speaker 1 (09:37):
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.

Speaker 2 (09:53):
My Wikipedia research tells me that the deepest hole on
Mars is nine and millimeters deep, which is not very impressive.

Speaker 1 (10:00):
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.

Speaker 4 (10:14):
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

(10:35):
If could.

Speaker 1 (10:36):
Having just unicellular organisms result in oil? Or do you
need bigger stuff to get oil?

Speaker 4 (10:42):
Oh wait, wait, we're going into oil now. I thought
we were talking about soil. So have we dropped the.

Speaker 2 (10:46):
S You dropped the eye and went to soils, and
now we're going to drop the S and good oils?

Speaker 4 (10:51):
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.

Speaker 2 (11:10):
Go, Holnd did just say terrestrial regolith? That means on Earth?

Speaker 4 (11:15):
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

(11:36):
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.

Speaker 1 (11:42):
But you said terrestrial realith. You use the R word.

Speaker 4 (11:46):
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.

Speaker 1 (11:55):
This cleared up an argument Daniel and I had.

Speaker 2 (11:57):
In the past.

Speaker 1 (11:58):
Thank you.

Speaker 2 (11:59):
It turns out you turn regolith into soil just by
adding hummus or hemus.

Speaker 4 (12:04):
You could add, yes, you could do the job with
hummus or other forms of humous.

Speaker 2 (12:09):
Bhemi is like magic, really, it sort of life giving.

Speaker 4 (12:12):
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

(12:33):
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

(12:53):
of sedimentary rocks, but they are far less common, fewer,
and further between than marine eediments.

Speaker 1 (13:00):
We were going to get back to oils, So.

Speaker 4 (13:02):
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

(13:27):
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.

(13:48):
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

(14:12):
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

(14:34):
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,

(14:56):
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.

Speaker 2 (15:12):
This sounds kind of complicated and not so easy to arrange.
How is it that we have so much oil on Earth?

Speaker 4 (15:18):
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.

Speaker 1 (15:38):
So Mars used to be warmer because it had flowing
water at one point was it that warm.

Speaker 4 (15:44):
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

(16:05):
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

(16:25):
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

(16:47):
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

(17:08):
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.

(17:30):
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

(17:51):
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

(18:13):
and keeps it from escaping.

Speaker 2 (18:15):
This is like a geological Rube Goldberg machine.

Speaker 4 (18:18):
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

(18:39):
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.

Speaker 1 (18:50):
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?

Speaker 4 (19:03):
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

(19:25):
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

(19:45):
is on a planet like Earth.

Speaker 2 (19:46):
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?

Speaker 4 (19:58):
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

(20:19):
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

(20:40):
how likely it would be. I appreciate the question, it's
worth articulating, but I cannot answer that.

Speaker 1 (20:45):
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.

Speaker 4 (20:59):
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,

(21:22):
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

(21:43):
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

(22:07):
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

(22:30):
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

(22:50):
connodants are?

Speaker 1 (22:51):
No?

Speaker 4 (22:52):
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

(23:14):
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

(23:34):
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.

(23:55):
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

(24:18):
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

(24:41):
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

(25:03):
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

(25:25):
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

(25:47):
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

(26:07):
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

(26:30):
on Wikipedia you can read if you're interested in exploring that.

Speaker 1 (26:33):
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.

Speaker 4 (26:43):
Yes, and if it's the wrong color, don't bother.

Speaker 1 (26:46):
Okay, and mars, we'll have none of this. So we're
we're out of luck there. But that's awesome.

Speaker 2 (26:51):
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.

Speaker 4 (27:09):
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.

(27:33):
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,

(27:53):
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.

Speaker 2 (28:09):
There's like sentiments of words that build up over time.

Speaker 4 (28:13):
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.

Speaker 1 (28:25):
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.

Speaker 4 (28:36):
Okay, good luck, everybody.

Speaker 2 (28:37):
I love talking to geologists. They rock.

Speaker 1 (28:40):
I bet Callen has never heard that.

Speaker 3 (28:42):
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.

Speaker 2 (28:53):
Now, thank you.

Speaker 1 (28:55):
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.

Speaker 2 (29:25):
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.

Speaker 1 (29:40):
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.

Speaker 2 (29:48):
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.

Speaker 5 (30:02):
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

(30:24):
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.

(30:47):
That is a great question.

Speaker 1 (30:49):
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?

Speaker 2 (31:03):
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

(31:25):
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

(31:47):
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.

Speaker 1 (32:06):
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?

Speaker 2 (32:15):
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

(32:36):
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

(32:58):
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

(33:18):
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.

Speaker 1 (33:39):
Is the answer going to be quantum entanglement or something?
Why do you all always make this so complicated?

Speaker 2 (33:45):
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,

(34:07):
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

(34:27):
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

(34:48):
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

(35:08):
when you shown the light brightly. So you just replace
the concept of light waves with probability waves and all
the same math works.

Speaker 1 (35:15):
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.

Speaker 2 (35:29):
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

(35:50):
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

(36:13):
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.

Speaker 1 (36:23):
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.

Speaker 2 (36:36):
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

(37:00):
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

(37:20):
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,

(37:42):
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,

(38:04):
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,

(38:25):
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

(38:48):
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

(39:10):
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.

(39:31):
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

(39:52):
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.

Speaker 1 (40:01):
So if it collapses at the two slits. Instead, you
get a totally different answer.

Speaker 2 (40:06):
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

(40:28):
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

(40:48):
know about the universe, so it's like a work in progress.

Speaker 1 (40:51):
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?

Speaker 2 (41:11):
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.

Speaker 5 (41:21):
Yes, thank you.

Speaker 2 (41:22):
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?

Speaker 5 (41:34):
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

(41:55):
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

(42:16):
or do some particles not hit the detector screen because
they actually hit the barrier somewhere instead of going through
the two slits.

Speaker 2 (42:24):
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.

(42:45):
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,

(43:05):
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.

Speaker 5 (43:22):
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.

(43:43):
I happen to I'm gonna be right in this little
space where there's a slit. But then it goes through
both slits.

Speaker 2 (43:52):
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

(44:13):
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,

(44:34):
and it's maintaining the uncertainty that allows it to make
that interference pattern.

Speaker 5 (44:37):
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.

Speaker 2 (44:46):
Mm hmmm, yeah, exactly. It doesn't have to collapse when
it hits the barrier.

Speaker 5 (44:50):
Oh gosh, sorry.

Speaker 2 (44:52):
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

(45:14):
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?

Speaker 6 (45:21):
Right right?

Speaker 2 (45:23):
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

(45:44):
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.

Speaker 6 (46:05):
Thank you, and we're back.

Speaker 1 (46:25):
Our final question of the day is a question from
Lewis on Discord, and here is his question.

Speaker 7 (46:33):
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.

Speaker 1 (46:54):
All right, Oh my gosh, there's so many problems on Mars?
Which ones should we try to solve?

Speaker 2 (46:59):
I'm excited that you're optimistic about this. I thought your
answer might be like, it's impossible to give up.

Speaker 1 (47:04):
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?

Speaker 2 (47:23):
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.

Speaker 1 (47:34):
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.

Speaker 2 (47:40):
Okay, let's see, all right, let's hold.

Speaker 1 (47:42):
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.

Speaker 6 (48:02):
Boo boo, boo boo.

Speaker 1 (48:03):
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.

Speaker 2 (48:18):
Daniel, Yeah, exactly, Yeah.

Speaker 1 (48:21):
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,

(48:41):
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.

Speaker 2 (48:50):
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

(49:10):
without our atmospheric bulletproof vest Kelly?

Speaker 1 (49:12):
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,

(49:34):
and I'm giving you reasons why it's worse. My pessimism
is winning, all right, I'm backing up.

Speaker 2 (49:40):
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.

Speaker 1 (49:50):
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

(50:11):
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,

(50:31):
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.

Speaker 2 (50:42):
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?

Speaker 1 (50:55):
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

(51:18):
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

(51:39):
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

(52:02):
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?

Speaker 5 (52:23):
Like?

Speaker 1 (52:24):
Are what are our solutions here?

Speaker 2 (52:26):
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

(52:46):
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

(53:07):
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.

Speaker 1 (53:24):
Okay, I feel like pestimist, I know.

Speaker 2 (53:31):
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

(53:52):
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.

Speaker 1 (54:06):
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

(54:27):
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

(54:47):
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

(55:08):
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

(55:29):
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,

(55:49):
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.

Speaker 2 (55:58):
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?

Speaker 1 (56:11):
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.

Speaker 2 (56:22):
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.

Speaker 1 (56:29):
Yeah, we don't know. Maybe you could sleep on the
racetrack and that would be enough, but I we don't know.

Speaker 2 (56:35):
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.

Speaker 1 (56:52):
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.

(57:15):
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.

(57:36):
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.

Speaker 2 (57:44):
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.

Speaker 1 (58:00):
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

(58:23):
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

(58:43):
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.

Speaker 2 (58:55):
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

(59:16):
of this technology to create horrendous outcomes?

Speaker 1 (59:19):
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

(59:41):
they'll have to deal with for their whole life because
you decided to tinker with their DNA, but just.

Speaker 2 (59:45):
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

(01:00:05):
a real risk if my partner was also an Ashkenazi Jew.

Speaker 1 (01:00:09):
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

(01:00:31):
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

(01:00:52):
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.

Speaker 2 (01:01:06):
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

(01:01:27):
some genetic decisions.

Speaker 1 (01:01:28):
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.

Speaker 2 (01:01:45):
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.

Speaker 1 (01:01:54):
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

(01:02:15):
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

(01:02:36):
to be doing quickly for the safety of our species.

Speaker 2 (01:02:39):
Wow, it's so hard to imagine what the future of
humanity holds. It can go in so many different directions.

Speaker 1 (01:02:45):
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

(01:03:06):
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.

Speaker 2 (01:03:21):
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.

Speaker 1 (01:03:34):
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

(01:03:54):
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

(01:04:17):
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,

(01:04:38):
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

(01:04:59):
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.

Speaker 2 (01:05:21):
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,

(01:05:42):
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

(01:06:02):
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,

(01:06:25):
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.

Speaker 1 (01:06:46):
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.

Speaker 2 (01:06:56):
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.

Speaker 1 (01:07:05):
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.

Speaker 2 (01:07:13):
Look, I only solve the problem for a minute. I
don't know's to lunch?

Speaker 1 (01:07:16):
You know, Well you got you know, incremental you gotta
let the market something something exactly.

Speaker 2 (01:07:23):
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,

(01:07:45):
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.

Speaker 1 (01:07:57):
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.

Speaker 2 (01:08:18):
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.

Speaker 1 (01:08:32):
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.

Speaker 2 (01:08:42):
I'm terrified what kind of grade we're going to get.

Speaker 8 (01:08:44):
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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