October 1, 2024 • 42 mins
As far as we know life evolved once in the universe – here on Earth in the form of life as we know it. Could life have originated in other conditions with different raw materials? If so, we may be sharing the planet with lifeforms we don’t recognize yet.
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Episode Transcript
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Speaker 1 (00:01):
Welcome to Stuff you should know, a production of iHeartRadio.
Speaker 2 (00:11):
Hey, and welcome to the podcast. I'm Josh and there's Chuck.
And we're doing it together, doing it, doing it. We're
just doing it together, and this is stuff you should know.
Speaker 1 (00:21):
That's right. I have the rainy day blues, you guys,
but we're doing it anyway.
Speaker 2 (00:26):
We're doing it together.
Speaker 1 (00:27):
The rain shouldn't stop an indoor podcast, right, No.
Speaker 2 (00:33):
But I'm with it. It's been raining too much lately
and it can get to you after a while.
Speaker 1 (00:37):
Yeah, that's right, I'll persevere. The sun is shining in
my head.
Speaker 2 (00:44):
Oh that's very pleasant.
Speaker 1 (00:45):
It's not true, but it's a nice thing to say.
Speaker 2 (00:48):
Okay, So that reminds me of that. I remember when
Pebbles and Bambam on Flintstones had like a brief singing career.
Speaker 1 (00:57):
Oh yeah, wasn't.
Speaker 2 (00:59):
It like, let's the sunshine in? Or there is something
there hit single head to do with sunshine?
Speaker 1 (01:04):
Well? I remember let the sunshine in? But was that
the Brady bunch? Was that Pebbles and Bam Bam you
let the sunshine in? Something something with the grin.
Speaker 2 (01:15):
I don't think it was either of them, not even
the Brady Bunch though. Well, at any rate, it just
reminded me of Pebbles and Bambam, so that did my
heart good too.
Speaker 1 (01:24):
Alrighty, So can I just briefly say what we're talking
about so people don't think this is about the fund Stones? Yeah,
although that'd be a fun episode.
Speaker 2 (01:32):
Actually, I agree, I think that is a future episode.
Good idea, all right.
Speaker 1 (01:38):
The shadow biosphere, which is to say, this notion, this
theoretical notion that perhaps, if you know, we're constantly looking
for life on other planets and it has been positive,
well what if there if that life exists here on Earth,
but it just doesn't look at all, and it's not
made up of all the things that make up life
(02:00):
as we know it here on Earth, and so we're
just either looking in the wrong places or not recognizing
it as something that's alive, or both. And that's the
shadow biosphere, this idea. It's pretty cool.
Speaker 2 (02:13):
Yeah, it is pretty cool. I mean. One of the
big problems that you run into when you're talking about
a shadows biosphere or plotting to look for other forms
of life that just don't conform to what we think
of as life as we know it. The big problem
is is we don't really have a working definition of
(02:36):
life as life as we know it, like us, microbes, birds, like,
there's not a real definition that covers all of them,
and there is one that scientists have agreed to generally
settle on. But if people who are into the shadow biosphere,
which is to say, usually a combination of astrobiologists and microbiologists,
(02:58):
it's where they're two feel overlap in a ven diagram,
that's where the shadow biosphere lives, they will say like,
this is holy inadequate, Like there are we need to
broaden the horizons or else we're never going to detect
anything that's not living.
Speaker 1 (03:14):
Yeah, and I'll tell you what, my friend, I hope
one day during the life of the show, we do
find life on other planets that significant, so you will
stop doing articles about it.
Speaker 2 (03:26):
Well, this is so yeah, okay, fair, fair, This is
a pursuit of astrobiology. But the thing that I find
the most fascinating is where microbiology comes in. And they're saying, yeah,
this would help us find or look for life off
of Earth. Yeah, but it'll also help us find life
on Earth. Like the idea that we share a planet
(03:47):
with other trees of life that aren't related to us
in any way, shape or form other than we we
share the planet and they function in ways similar that
life as we know it functions, but we're not related.
Speaker 1 (03:59):
Yeah.
Speaker 2 (04:00):
Yeah, I think that's neat.
Speaker 1 (04:02):
I think it's totally neat. And here's the other thing too,
is if, and this is a pretty important note, if
we do find something here on life on Earth that
is like a shadow life form of some sort, we're
probably talking about microbes. Just so people don't get super
excited about the idea of chuds being a real thing.
(04:24):
That's not a real thing. We're not going to We're
not going to go deep down enough to find any
cannibalistic humanoid underground dwellers sadly. So what we're talking about
here microbes, and what we're talking about is this idea
put forth by a very smart woman named Carol Cleland
from the University of Colorado Go buffaloes. And I think
(04:46):
the way she came about it was like you hear
about like she came about it. Honestly, I think this
is like one of those times because she was in Spain,
she was observing some molecular biologists. They were looking for
soil mic and microorganisms looking through these samples and she
was like, hey, they went see, and she said, how
(05:08):
do you know, like that you found something new, like
a new microbe And they said, well, and I'm not
going to say this in Spanish because I didn't translate
at all. I just know what yes is. See, but
they said, well, what we do is we look until
we find something that looks like it might hold some promise.
Then we you know, we've looked at it under a microscope.
(05:29):
Then we put it in a Petri dish and just
grow the heck out of it and then isolate its
DNA and then look at the genome and see, like, hey,
what does this look like? And then she went, oh,
that's kind of cool, but I have another question. It's
kind of like Tom Hanks and Big like.
Speaker 2 (05:44):
They get still here.
Speaker 1 (05:47):
She said, well, what if it's not related to life
on earth? Like, how would you even know? You're like,
how to recognize something as being alive? And they all
shrugged and she wrote a book about it.
Speaker 2 (05:58):
Oh see, I imagine them all for and one of
them just drops the Petrie dish without they just drop
like they can't believe what they've just heard. They're stunned.
Speaker 1 (06:07):
Yeah, and COVID.
Speaker 2 (06:09):
So so, Carol Cleveland makes a really excellent point. And
like you said, this kicked off the idea of shadow biospheres,
and in fact she coined that term. But what she's
saying is that our process of looking for life would
just walk right past anything that doesn't conform to our
understanding of life. But that still is living in a
(06:30):
certain definition of things.
Speaker 1 (06:33):
Nailed it.
Speaker 2 (06:33):
Yeah, So just to kind of step back for a second,
there there is a some there's a consensus among scientists
that life conforms to a few rules. This is the
the generally agreed upon definition of life. It's carbon based.
Anything else is non living. You know, you look at
a piece of courts it's from silicon, I think not living.
(06:58):
Great example thinks it's programmed by DNA and RNA. Right,
so it has transcription of its genetic code, and that
is just it does not live without that. Those things
are built by amino acids and proteins. Those are the
basic building blocks of the organism. It's self replicating very important.
(07:24):
And then it also evolves according to Darwinian principles, which
is to say that the best properties and traits are
selected for over time. So if you put all those
things together, you have a pretty good idea about life.
But again, this is a really narrow definition, and if
you really kind of look at it, you're like, this
(07:45):
is there's a lot of room for other things to
function in a manner that's living that doesn't necessarily use
DNA or RNA, that doesn't use amino acids or at
the very least the amino acids that we use, and
it might not even be carbon based. Like maybe we
(08:05):
can broaden this a little bit, and that's the pursuit
of shadow biosphere.
Speaker 1 (08:09):
Yeah, and Carol Cleland was right in the money said
she wrote a book. It's really a paper, but you know,
she could bind it like a book, probably sell it
in a store, sure, But it was called the Possibility
of Alternative Alternative Microbial Life on Earth. We're also going to,
you know, talk a little bit about looking on other planets,
because we've talked a lot about that and suffice to say,
(08:32):
when we're looking for life on other planets where you know,
we're always looking for like an earth like place where
something like life as we know it could exist kind
of in the same way. But she was like, this
stuff might be right under our noses, everybody right, And
here's a paper about it, and I think it was
pretty smart paper. There was a should we talk about
the central dogma?
Speaker 2 (08:53):
I guess yeah, I think we need to.
Speaker 1 (08:55):
Yeah. So you know, you went over what life on
Earth contained, but the central dogma is a little more specific.
It was first proposed by Francis Crick in the nineteen fifties.
That is that DNA, the nucleic acid that we know
and love, has instructions for building all the proteins that
are required for something to be alive. You also have RNA,
(09:19):
which copies those instructions to take them to the ribosomes,
which also exists. Because that reads that RNA and assembles everything,
all those amino acids to make each protein, and bada
bing bada boom, you have life.
Speaker 2 (09:33):
Right, And so you take that process and you end
up with what's called the origin of life, the genesis
of life here on Earth.
Speaker 1 (09:43):
Genesis.
Speaker 2 (09:44):
We've talked about that. That's the scientific way of.
Speaker 1 (09:46):
Saying, well, okay, we go put on my lab coat.
Speaker 2 (09:51):
We've talked about this before multiple times. Remember we did
an episode on panspermia. We've done a bunch of episodes
that I think this primordial soup came up. And that's
the whole idea that either in some shallow tidal pool
or you know, some warm part of the ocean or
some body of water, there was a bunch of those
(10:13):
basic building blocks of life, amino acids, proteins floating around
and that somehow a self replicating process got kickstarted. And
the self replicating process is considered what's called a privileged function,
This idea that this mechanism for creating life was present
(10:34):
at the outset and is still around today, so we
self replicate. A couple others were metabolism, that's another suggestion
for the privileged function that kickstarted life. Or then compartmentalization
like having something to hold all of these processes in
like a bag of guts. Basically, so one of those
they say is what was responsible for kickstarting this process
(10:57):
of life, and that somehow, some a bunch of chemical
reactions started a chain reaction that became self sustaining that
eventually turned into increasingly complex processes, organelles, and eventually living organisms.
That's how life developed. That's the idea behind the primordial
(11:18):
soup that the central dogmas based on that's right.
Speaker 1 (11:22):
But in Cleveland's paper, she was like, well, hold on
a second, that's great, what a story. We love it,
we all believe it. But what if this happened like
more than one time. What if it happened multiple times
right here on Earth there were just different conditions in
different places, different chemicals came together. And what if that
happened and these are the shadow microbes? And what if
(11:45):
this stuff is still there? And the reason that we
haven't found it is because we're looking for again for
life that we understand as being alive and the ramifications
that would have not only to find stuff like that
here on Earth, but you know this idea that when
we go out and look in outer space for life
on other planets again we're looking for earthlike, you know,
(12:08):
atmospheres and Earth like conditions. She was like, well, what
if we're looking on the entirely wrong planets. There could
be stuff that's alive because we're just not looking in
the right places because we have such a narrow definition.
Speaker 2 (12:21):
Yeah, and we definitely have found increasingly extremophile organisms, like
for a long time we thought that organisms couldn't survive
past one hundred and twenty something degrees farenheight. Then we
found some extremophiles that can survive around hydro thermal events
that are as hot as two hundred and twelve degrees farentheight. Like, okay,
(12:43):
that's pretty awesome, but it's still life as we know it,
you know, like they're crazy in their adaptation, but they
still function according to the properties of life as we
know it. What Carol Cleland and others are saying is like, Okay,
we'll keep looking in even more extreme and vironments and
eventually you may find something that has had to adapt
(13:04):
to such an extreme environment. It uses different processes or
different raw materials that life as we know it could
not possibly use. And there you have your first shadow
bio organism.
Speaker 1 (13:19):
I think we should pick a great rest here. Rest.
Speaker 2 (13:24):
We'll be back everybody after this rest.
Speaker 1 (13:56):
And lo, the podcasters rested low and then on day
two they got on with the show. We should mention,
by the way, we did a pretty good episode on extremophiles, yeah,
a while back, So just if you haven't heard it,
you should just look up on the search engine of
your choice extremophile so if you should know, pretty neat.
(14:16):
But back to the shadow biosphere. You know, we mentioned
the fact that you know, Carol Cleveland's beating that drum, saying,
what if it's not something that we recognize because we
just don't recognize it as life as we know it.
And then she started digging in and she was like,
here's the thing. DNA and RNA aren't the only building
blocks of life. In theory. They are made of base
(14:40):
pairs of nucleic acids. For DNA, it's a D nine
cyanine quinine, and thymine. For RNA it's thymine that is
swapped out for ucell. But there are other three are
the same, but there are more nucleic I believe there's
six more nucleic acids that exists exist in nature. So
(15:02):
you know, why are we not even considering the fact
that those could be a part of life in a
way that we don't fully understand.
Speaker 2 (15:09):
Right, And first, ursill sounds like over the counter urinary
tract infection treatment totally does. Secondly, I could not, for
the life of me and I really looked find what
the other six nucleic acids are. I can't find it, Chuck.
But in that search I did come across something called
(15:29):
the hatch emoji DNA, which is those four at, which
is always together in GC, which are always together to
form those base pair nucleotides that eventually build up into DNA.
And they added p z B and.
Speaker 1 (15:46):
S and let's see them right.
Speaker 2 (15:48):
Well, that's four, so there's still two many. But the
really interesting thing that they found is that if you take,
if you rearrange say the original four bay pairs, or
you add these other brand new four base pairs and
run them through a ribosome, the ribosome, if you arrange
(16:09):
it correctly, and they're made of nucleic acids, the ribosome
will be like, okay, I'm transcribing this, So it's entirely possible.
They proved that it's possible that life could have evolved
separately from us by using different amino acids but similar mechanisms.
So maybe we are or could be, in this sense
(16:32):
distantly related to them, like maybe in the primordial soup,
but it branched off so early that for all intents
and purposes, it's non living life as far as our
definition of life goes.
Speaker 1 (16:44):
Yeah, well, nice job finding four of those six letters.
At least, let's just call the other two FU.
Speaker 2 (16:52):
Science.
Speaker 1 (16:53):
Yeah, so that's how DNA and RNA could be you know,
different as we know it. The same thing is true
for amino acids. All the proteins are built from the
same combination of twenty amino acids, because when Earth formed,
those were the twenty amino acids that, in a Darwinian sense,
(17:14):
were most successful making proteins that survived when life emerged.
There are five hundred we're not gonna name them, five
hundred other amino acids, or more than five hundred amino
acids on Earth. So yeah, totally. So it's just the
fact that Earth started when it did that those particular
twenty amino acids were the ones that were good at
(17:34):
doing what needed to be done to make things that
survived here. But it could have been, you know, at
a different time. It could have been any other combination
of amino acids, and they're.
Speaker 2 (17:43):
Still out there exactly. So a lot of scientists are like, well,
that just goes to show you that life as we
know it is the only kind of life. If we're
using the same twenty amino acids and there's all these
others out there, these are the ones that got selected
for These are the ones that worked in the primordial
soup and caroclelans forward again with her index finger raised
and says, Okay, I can see where you're coming from.
(18:06):
But again, as I said before, if life emerged in
other places, in other situations, under other conditions, in the
primordial soup, it's entirely possible that completely different combinations of
the other kinds of amino acids were the most usable,
and we're selected for that. And again, this is how
the shadow of biosphere could have started. And another petri
(18:28):
dish got dropped. And these guys are starting to second
guess undermining Carol Cleland, or even attempting to because she
just keeps facing them over again.
Speaker 1 (18:39):
Yeah, and they're like, well, how would that have happened
or how could that happen? She said, I don't know.
How about a meteor sucker because meteorites have fallen to
the Earth and asteroids that basically plant stuff on Earth
that come from another place. There have been meteorites that
have fallen that are carrying up to eighty other amino acids.
(18:59):
And her whole theory is it like, what if this
has happened, and maybe it's happened repeatedly, and again we
just don't know about it because we're not looking correctly, right.
Speaker 2 (19:11):
So, yeah, the panspermia episode that was the basis of it,
that Earth got seated with the necessary ingredients for life
from space. Right, that's right. So there's another peculiar aspect
of life as we know it that doesn't really make
sense to us, and I don't fully get how it
would tie into the shadow biosphere. So if you do,
(19:34):
let me know. But the best I can understand is
that because we don't know it, and because it's like
it just seems like a random, arbitrary development in life
as we know it, that it suggests things could go
the other way and maybe they have elsewhere on Earth.
Is that how you read it too?
Speaker 1 (19:54):
Yeah? I think so. Okay, just like an example of like,
see this can happen.
Speaker 2 (19:58):
Right, Okay, good, That's what I'm taking as too. And
we're talking about chirality, and chiralness is handedness and Greek
you're either right handed or you're left handed, or you
could be ambidextrous. But that's neither hum nor there. When
we're talking about cellular biology or molecular science, which is
what this pertains to, and if you make a bunch
(20:21):
of sugars or a bunch of amino acids in the lab.
Some are going to be left handed and some are
going to be right handed. But as far as life
on Earth is concerned, only left handed amino acids and
only right handed sugars can be useful as the building
blocks of life. So there's right handed amino acids and
(20:44):
left handed sugars, but they are completely useless to us
because all life on Earth only uses left handed amino
acids and only uses right handed sugars. And we just
don't know why.
Speaker 1 (20:58):
Yeah, and if this sounds like, all right, guys, what
are you talking about here with these hands, it's not hands,
it's the direction that their atoms are oriented. Yeah, they
talk about it in terms of handedness. I think just
as a well, I hate to say it is a shorthand.
So dumb humans like us can understand what they're talking
about at least halfway right.
Speaker 2 (21:19):
And so, because there's left handed and right handed amino acids,
they are mirror images of one another. They're constructed the
exact same way. They're constructed with the exact same components
to make up these molecules, but they are mirror images.
So if you overlay them, they're not twins mirror images.
So in exactly the same way. If you hold your
(21:42):
hands out in front of you, palms down so the
tops up, and you just kind of hold one over
the other, they're not twins. They're mirror images of one another.
And that's exactly true with amino acids and sugars. They
each have a mirror image. And again, only one kind
is useful to life. The other ones just get spit out.
So what if, again, under different conditions, at some point
(22:05):
in the past, there were organisms that learned to use
the other kind left handed sugars and right handed amino acids,
that would certainly qualify as a shadow biosphere bioorganism.
Speaker 1 (22:20):
Yeah, and we have synthesized these in labs. But what's
the deal. What I don't understand. If they were able
to synthesize it, that means that it did already exist,
but it just isn't anything that was alive.
Speaker 2 (22:35):
Yeah, I don't know exactly what they did. They built
a cell that uses right handed sumino acids. Yeah, yeah,
and they I don't know if it was living or not.
I don't think it was living or else they would
be like we created artificial life here. I don't think
anyone's ever done that. I think they just created the
(22:56):
structure of it. Like if there if there was something
like a cell that use that kind of stuff, this
is what it would be structured as. The whole reason
they built it was to try to attract things like
chiro viruses that function using the opposite stuff that we
use for life. It was a honeytrap, is the way
that they put it.
Speaker 1 (23:15):
Like they take it out to a club and set
it on a bar table and they're like, hello, everybody,
exactly right.
Speaker 2 (23:21):
So nothing came along and took the bait, But that
doesn't mean it's not there. The better argument against things
like that living, if you asked me that I ran across,
is that if you did have something like that that
could consume other things, it would have no natural predators.
It would it would not be able to be infected
(23:43):
by any of the known viruses we have. It would
be unstoppable, and it would replicate in such an unchecked
manner that it would apocalyptically destroy the food web based
on whatever, you know, one microbe that it feasted on.
And because that's not happen, and there's a pretty good
chance that there's no such thing as that.
Speaker 1 (24:04):
Yeah, I guess now we can talk a little bit
about the last universal common ancestor or the LUCA, which
is the idea that all life on Earth can be
traced back to this very first functioning cell that started
the whole party. If we believe in something like the
shadow biosphere, there can still be a last universal common ancestor,
(24:25):
I think in terms of what created our life. But
we have to consider the fact that there were multiple
genesis that happened at a certain point and you know,
maybe they just didn't evolve because you know, part of
that opening four things that we talked about was that
things evolved in a sort of the Darwinian sense that
(24:45):
we recognize. But the idea of the shadows biospheres, maybe
these things did occur at various sort of calm periods
on Earth where there weren't you know, ice ages, or
it wasn't being bombarded by asteroids, and that there's still
they just never evolved. They're just sort of trapped.
Speaker 2 (25:02):
Yeah, that's one example. There's another explanation that they might
be in places we haven't explored yet, so like there
could be you know, life on the surface of Earth
and then we find microbes all the way down to
some you know level and it gets too hot for them,
and then it's a dead zone. Well maybe beyond the
dead zone there's these you know, shadow biosphere organisms. And
(25:23):
then another argument I saw against the idea. So a
lot of scientists are like, sure, it's entirely possible there
were different origins of life, but the other one sputtered out,
only ours continued on a lot of that's not a
very controversial idea. What's controversial is that it didn't sputter out,
that they just evolved and we share Earth with them, right,
(25:44):
But a lot of the arguments against that state that, Okay,
well maybe it did make it beyond the sputtering stage,
and it was you know, we shared the primordial soup
with it, but it got absorbed into us and now
it's a part of us, but you know, not really anymore.
And that misses the point because what they're talking about
(26:05):
is lateral gene transfer, where like say one cell just
takes over another cell and they share DNA from that
point on. That's totally missing the point. Like that would
not be a shadow organism, it'd be an early additional
ancestor to us. This is stuff that we couldn't possibly have,
you know, mixed with to become us or else it
(26:27):
wouldn't be a shadow bio organism. It would just be
another component that created life as we know.
Speaker 1 (26:34):
Would That's right, And lateral gene transfer was totally an
a cappella skiking group from the seventies, a gospel group, oh,
led by a guy named Gene Nice.
Speaker 2 (26:44):
Nice.
Speaker 1 (26:44):
Yeah, I've got the record. It's not even a joke.
Speaker 2 (26:48):
Are you kidding? You're not kidding? Ah, wow, you did
get me. That was finally, Well, we're pretty wacky, so.
Speaker 1 (26:58):
Oh goodness. It is a meal, best serve cold.
Speaker 2 (27:01):
Do you do you want to take a break and
savor that for a little while.
Speaker 1 (27:04):
Uh yeah, sure, let's go ahead and take a break.
I'm going to take another nap and dream about getting
Josh and then we'll be right.
Speaker 2 (27:12):
Back, all right, Chuck. So we said that, or I
(27:44):
should say, you said at the outset that nobody's looking
for you know, some silicon were wolf or something so great.
So instead there were we're looking for my crubs. And
the reason that everybody agrees if there is a shadow
by its microbial life is a couple of reasons. One
(28:04):
we could look at a microbe and look right past it.
They don't have faces, they don't have tails, they don't
have hair, they don't really have any features that would
really stand out just visually. We have to really examine
them to find the differences that we would be looking for.
And then on top of that, we've only cultured and
described less than one percent of all of the estimated
(28:25):
species of microbes on Earth, right so we have very
little understanding in the big picture of the microbial life
we share Earth with. So it's entirely possible we just
haven't stumbled upon one yet. But that doesn't mean it's
not there in that other ninety nine percent of the
kinds of microbes on Earth with us right.
Speaker 1 (28:44):
Now, Yeah, for sure. And you know we've kind of
walked around this very plain statement. But the plain statement
is look where we think or look where we so
far think that nothing here can live, because that might
be a great place to start, you know, if we're like,
nothing can live in the dead sea micro organisms, because
(29:06):
it's just it's so full of saline that we just
know nothing could live, Like, well, maybe start there, or
you mentioned earlier the fact that things we didn't think
anything could sustain life greater than like one hundred and
twenty two degrees fahrenheit. But then we discovered colonies of
bacteria that could. We're like, well, that's evidence right there
(29:27):
that maybe we should look in like really really hot places,
really really cold places, really acidic places, really base places.
Anything on the list that says human life can't exist there,
maybe start looking there.
Speaker 2 (29:40):
What's crazy is when we have looked there, we keep
finding stuff that can exist, like life that yeah, doing
just fine there that just should not be there. The
best example I found are types of I think slime
mold maybe or algae that it lives in abandoned uranium
(30:02):
minds so this place is so crazy radioactive, No life
should be able to survive there, and yet they think
these things are actually taking that radiation and using it
as chemical energy. And then there's also a kind of
single cellular life that they found growing in one of
the abandoned chernobyl reactors. Again should not be aware because
(30:25):
of the radioactivity. But these things still conform to the
basic principles of life as we know it. The point is, though,
is you just keep thinking in more and more extremes,
and you know, maybe we'll find it like the upper
atmosphere is the one that suggested because no life's supposed
to be able to live up there because of the
(30:45):
cosmic rays and the temperature and all that stuff. It's
just not a pleasant place to live from what I understand.
And then other people are like, Okay, if we keep
looking and in these more extreme environments and we're just
finding life as we know it, maybe we should look
around and see if we find anything weird in places
(31:05):
like right under our very noses. And one of the
big ones that has been touted is desert varnish. And
this one, from what I can tell, is still the
jury's out whether it's a shadow bio organism.
Speaker 1 (31:20):
Yeah or not or not. You're hanging out there like
a chad. So yeah, if you've ever been out to
the desert in the United States, if you've ever driven
around like Utah or Arizona, maybe even Colorado, maybe New Mexico,
you might have been driving along and seeing like a
(31:41):
very sheer sort of cliff face, and within that cliff
face you might be like, oh, that's just weird, sort
of shiny, dark area of it. There are always really
arid environments. Indigenous peoples used to create petroglyphs, so instead
of like you know, writing on something, they would scrape
away that varnish to make their art for the original
(32:04):
lighter colored earth underneath it. But I mean, I've seen
these things in person. I've driven by it, and I
didn't know what it was. I just figured it was
dark rock or something. But it's called desert varnish, and
scientists have been fascinated for a long long time. One
reason is because it grows about the pace of a
width of the human hair every millennium, and because that
(32:27):
happens so slowly, they were like, well, this is just
a geological process that's going on, maybe the sun hitting it,
some sort of chemical reaction takes place. But they found
that that's it's actually a living thing, right.
Speaker 2 (32:42):
They don't know there's no geochemical process that accounts for it.
There's no biological process that accounts for it. They just
don't know. It's largely manganese in nature. But the problem
is it's not drawing manganese out of the rock, like
a lot of these rocks don't have any manganese or
have such trace amounts that it certainly wouldn't account for
this desert varnished. So they just don't know how this
(33:07):
stuff is growing or what it is. But it's probably
the greatest contender right now for a shadow organism from
what I can tell. Like they're like, well, then it
must be a geochemical process. We just don't understand. And
it's like, maybe what you're calling geochemical is actually life
in a different manner.
Speaker 1 (33:26):
Yeah, I guess there's just said the theory that it's
alive that is biochemical.
Speaker 2 (33:30):
Yeah. There was also one that was like we founded everybody,
we found the shadow organism and it went downhill from
there back in twenty ten.
Speaker 1 (33:40):
Yeah, that was gfag dash one that is a bacterium
that was found in Mono Lake, California, And they were like, well,
this bacterium is really weird because it doesn't it's not
sort of playing by the rules that we understand. Because
if you're going to be a living thing to make
DNA and RNA, you need phosphorus, and it doesn't look
(34:02):
like this thing is using phosphorus. It looks like it's
using arsenic, which would be a huge, huge mind And
so they thought GFA j dash one, you're you're the dude,
And everyone was really hot on this idea, and then
they did follow up experiments and very sadly found out
that it used very very very small amounts of phosphorus
(34:25):
and it just wasn't instantly evident. So they're like, all right,
just another extremophile. That's that we understand.
Speaker 2 (34:33):
Yeah, now we know.
Speaker 1 (34:34):
So cool.
Speaker 2 (34:35):
That's another benefit of it, Like we're finding stuff because
we're out looking for shadow life. We're finding other life
still too, So that's I mean, it's not like they're like, oh,
another extra file. It's never been seen in the history
of humanity.
Speaker 1 (34:49):
Just juke it.
Speaker 2 (34:50):
That's an interesting way that you pronounced that. I've been
in my head pronouncing it gufage, you know. So okay,
let's move on. Let's move on to life with the
y chuck, because I think that that's a good next
(35:12):
place to start.
Speaker 1 (35:13):
Yeah, there's a guy. Well here's the idea, is that, like, hey,
maybe there is just we should just accept the idea
that l i f E isn't all we think it is,
and maybe it's broader than that and maybe or maybe
we just need another definition l y f E. And
I think that was put forward by an astrobiologist named
(35:33):
Stuart Barleot not Bartlett, just Barlatch, And he said, well,
maybe that is the l y f E definition is
just any system and this is a quote any system
that fulfills all four processes of the living state, namely dissipation,
auto catalysis, catalysis either one, catalysis, homeostasis, and learning.
Speaker 2 (35:58):
Yeah, so just to get into it real quick, dissipation
means that it dissipates energy or something like waste brought
byproducts like heat. That's a big one. Or else it'll
overheat and die, or it will never poop out its
food and will die from that. That's it's just a
really easily overlooked component of something organism that can keep going. Also,
(36:22):
it needs to be able to make more copies of itself.
That's that auto calysis, catalysis, auto catalysis, Sure, that's that's
important because what it's doing is it's creating a process
that creates another version of itself and also a product
that triggers that process over again, so it can just
(36:43):
keep going. It also has to be able to maintain homeostasis,
so it can't just go totally haywire anytime you know,
somebody nearby coughs. And then lastly, it's got to be
able to record information about the environment like this is
how you keep from going haywire when somebody coughs, and
it can be encoded in some way, shape or form,
(37:06):
so it can be passed on to the replicants of itself. Yeah,
that's life with a why. And I think that's exactly
the kind of broadened definition that we need. And the
other thing about life with a why, that includes life
with an eye, like life as we know it, and
(37:26):
just saying life with an eye is so much less
clunky than life as we know it, and it falls
under a larger umbrella. So it's a broader definition that
includes life as we know it, but also potentially includes
members of the shadow biosphere as well.
Speaker 1 (37:41):
Yeah, and what this potentially means is if there is
life with a why here or elsewhere, that means that
kind of anything is possible. It doesn't mean that, hey,
there's intelligent life out there, but it doesn't mean there's not.
I mean it would certainly kind of interest toward that idea.
In a very real way, we found that there is
a different kind of life we just never understood before
(38:04):
here or elsewhere. There's an astrophysicist named Paul Davies really
smart guy obviously who has done a lot of scholarship
work about intelligent life elsewhere, and he talks about timing
a lot, like, you know, Earth happened the way it did,
and it's kind of like what we touched on earlier.
(38:24):
Earth happened the way it did because of the timing
of it all. We've been around for about four and
a half billion years, and we won't be around in
about a billion years, Like the Earth will be scorched
basically by the Sun, and it was just sort of
cosmic luck that everything evolves when it did as it did,
because there's a kind of a short window in the
(38:46):
grand scheme of things between when something starts happening and
being able to get to the point where you have
like intelligent life like human beings and the planet being
scorched or being blasted away by a large Yeah.
Speaker 2 (39:00):
So Paul Davies's argument kind of suggests that life is
probably pretty rare, if not singular, like the only we
do know that life emerged once in the entire universe
that led to us in all life as we know it,
but that's it. We don't know that life emerged anywhere
else any other time, including on Earth. And that's one
(39:22):
of the things that would make detecting a shadow biosphere
so amazing, is it would it would essentially immediately say
the universe is teeming with life. If life developed two
different ways on the same planet. That strongly suggests that
not only is there life elsewhere in the universe, but
(39:42):
that biology is as immutable a cosmic or universal law
as physics or chemistry. Right that if you have even
just a few components put together that that gives rise
to life, biology is going to take over and life will.
That's ultimately the most exciting thing that gets scientists jazzed
(40:05):
about looking for the shadow biospheres. What the implications that
we'll have about us sharing life elsewhere in the universe.
Speaker 1 (40:13):
Yeah, totally pretty cool stuff.
Speaker 2 (40:15):
Huh Yeah, I like it, Chuck, I'm glad that we
did this. Thanks for doing it with me.
Speaker 1 (40:21):
It was fun. We got through it.
Speaker 2 (40:22):
Yeah, we did well. Since we got through it, everybody,
that means it's time for listener. Mayo.
Speaker 1 (40:30):
I'm gonna just read this one from Joel because it's
kind of just a fun little little ditty. Hey, guys,
I guess it's not a diddy. It's a story. First off.
I want to say thanks for all the work you
do to create an enjoyable and informative listening experience. I've
been a casual listener since twenty eighteen, and your show
has positively redirected the course of my day or staved
(40:50):
off boredom through long winter nights. Because I live on
Salt Spring Island, BC, off the coast of Vancouver Island
and work at a golf course there. Today I was
mowing the fairways on a wet and dreary morning. I
put on the Manson Murders podcast and relax into my work.
Part Way through, Dennis Wilson came into the story and
Chuck mentioned his solo album. I think it's called Pacific
(41:14):
Ocean Blue.
Speaker 2 (41:14):
Maybe I don't know.
Speaker 1 (41:16):
I think so great record. Feeling a little low, I
decided to pause the podcast and listen to the full album.
I listened to all the songs as I continued my
mo lines. Truly a wonderfully enjoyable album. Thank you for
that excursion into the music. Once the album finished, I
listened to the mower for a few minutes and then
resumed the podcast. And the first words I hear are
(41:37):
Chuck saying Eventually they leave Dennis Wilson's house and I
chuckled as I genuinely felt I had just been in
his house myself.
Speaker 2 (41:45):
Nate.
Speaker 1 (41:46):
Anyway, short little story for me. Thank you for the
years of entertainment. Keep up the great work that is
from Joel. And Joel sent a picture of that fairway
mode while listening to Pacific Ocean Blue and Joel as
a beautiful golf course and I would love to play
it one day.
Speaker 2 (42:03):
Oh, very nice. Yeah you're a golfer. I forget that
sometimes I am.
Speaker 1 (42:06):
I'm not very good, but I enjoy putting the phone
away for five hours and walking around with my buddies
in the sunshine.
Speaker 2 (42:12):
Very nice. Well, thanks a lot, Joel, much appreciated. We
love stories like that, And if you want to be
like Joel, send us an email. Send it off to
stuff podcast at iHeartRadio dot com.
Speaker 1 (42:26):
Stuff you Should Know is a production of iHeartRadio. For
more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows.
Welcome to Stuff you should know, a production of iHeartRadio.
Speaker 2 (00:11):
Hey, and welcome to the podcast. I'm Josh and there's Chuck.
And we're doing it together, doing it, doing it. We're
just doing it together, and this is stuff you should know.
Speaker 1 (00:21):
That's right. I have the rainy day blues, you guys,
but we're doing it anyway.
Speaker 2 (00:26):
We're doing it together.
Speaker 1 (00:27):
The rain shouldn't stop an indoor podcast, right, No.
Speaker 2 (00:33):
But I'm with it. It's been raining too much lately
and it can get to you after a while.
Speaker 1 (00:37):
Yeah, that's right, I'll persevere. The sun is shining in
my head.
Speaker 2 (00:44):
Oh that's very pleasant.
Speaker 1 (00:45):
It's not true, but it's a nice thing to say.
Speaker 2 (00:48):
Okay, So that reminds me of that. I remember when
Pebbles and Bambam on Flintstones had like a brief singing career.
Speaker 1 (00:57):
Oh yeah, wasn't.
Speaker 2 (00:59):
It like, let's the sunshine in? Or there is something
there hit single head to do with sunshine?
Speaker 1 (01:04):
Well? I remember let the sunshine in? But was that
the Brady bunch? Was that Pebbles and Bam Bam you
let the sunshine in? Something something with the grin.
Speaker 2 (01:15):
I don't think it was either of them, not even
the Brady Bunch though. Well, at any rate, it just
reminded me of Pebbles and Bambam, so that did my
heart good too.
Speaker 1 (01:24):
Alrighty, So can I just briefly say what we're talking
about so people don't think this is about the fund Stones? Yeah,
although that'd be a fun episode.
Speaker 2 (01:32):
Actually, I agree, I think that is a future episode.
Good idea, all right.
Speaker 1 (01:38):
The shadow biosphere, which is to say, this notion, this
theoretical notion that perhaps, if you know, we're constantly looking
for life on other planets and it has been positive,
well what if there if that life exists here on Earth,
but it just doesn't look at all, and it's not
made up of all the things that make up life
(02:00):
as we know it here on Earth, and so we're
just either looking in the wrong places or not recognizing
it as something that's alive, or both. And that's the
shadow biosphere, this idea. It's pretty cool.
Speaker 2 (02:13):
Yeah, it is pretty cool. I mean. One of the
big problems that you run into when you're talking about
a shadows biosphere or plotting to look for other forms
of life that just don't conform to what we think
of as life as we know it. The big problem
is is we don't really have a working definition of
(02:36):
life as life as we know it, like us, microbes, birds, like,
there's not a real definition that covers all of them,
and there is one that scientists have agreed to generally
settle on. But if people who are into the shadow biosphere,
which is to say, usually a combination of astrobiologists and microbiologists,
(02:58):
it's where they're two feel overlap in a ven diagram,
that's where the shadow biosphere lives, they will say like,
this is holy inadequate, Like there are we need to
broaden the horizons or else we're never going to detect
anything that's not living.
Speaker 1 (03:14):
Yeah, and I'll tell you what, my friend, I hope
one day during the life of the show, we do
find life on other planets that significant, so you will
stop doing articles about it.
Speaker 2 (03:26):
Well, this is so yeah, okay, fair, fair, This is
a pursuit of astrobiology. But the thing that I find
the most fascinating is where microbiology comes in. And they're saying, yeah,
this would help us find or look for life off
of Earth. Yeah, but it'll also help us find life
on Earth. Like the idea that we share a planet
(03:47):
with other trees of life that aren't related to us
in any way, shape or form other than we we
share the planet and they function in ways similar that
life as we know it functions, but we're not related.
Speaker 1 (03:59):
Yeah.
Speaker 2 (04:00):
Yeah, I think that's neat.
Speaker 1 (04:02):
I think it's totally neat. And here's the other thing too,
is if, and this is a pretty important note, if
we do find something here on life on Earth that
is like a shadow life form of some sort, we're
probably talking about microbes. Just so people don't get super
excited about the idea of chuds being a real thing.
(04:24):
That's not a real thing. We're not going to We're
not going to go deep down enough to find any
cannibalistic humanoid underground dwellers sadly. So what we're talking about
here microbes, and what we're talking about is this idea
put forth by a very smart woman named Carol Cleland
from the University of Colorado Go buffaloes. And I think
(04:46):
the way she came about it was like you hear
about like she came about it. Honestly, I think this
is like one of those times because she was in Spain,
she was observing some molecular biologists. They were looking for
soil mic and microorganisms looking through these samples and she
was like, hey, they went see, and she said, how
(05:08):
do you know, like that you found something new, like
a new microbe And they said, well, and I'm not
going to say this in Spanish because I didn't translate
at all. I just know what yes is. See, but
they said, well, what we do is we look until
we find something that looks like it might hold some promise.
Then we you know, we've looked at it under a microscope.
(05:29):
Then we put it in a Petri dish and just
grow the heck out of it and then isolate its
DNA and then look at the genome and see, like, hey,
what does this look like? And then she went, oh,
that's kind of cool, but I have another question. It's
kind of like Tom Hanks and Big like.
Speaker 2 (05:44):
They get still here.
Speaker 1 (05:47):
She said, well, what if it's not related to life
on earth? Like, how would you even know? You're like,
how to recognize something as being alive? And they all
shrugged and she wrote a book about it.
Speaker 2 (05:58):
Oh see, I imagine them all for and one of
them just drops the Petrie dish without they just drop
like they can't believe what they've just heard. They're stunned.
Speaker 1 (06:07):
Yeah, and COVID.
Speaker 2 (06:09):
So so, Carol Cleveland makes a really excellent point. And
like you said, this kicked off the idea of shadow biospheres,
and in fact she coined that term. But what she's
saying is that our process of looking for life would
just walk right past anything that doesn't conform to our
understanding of life. But that still is living in a
(06:30):
certain definition of things.
Speaker 1 (06:33):
Nailed it.
Speaker 2 (06:33):
Yeah, So just to kind of step back for a second,
there there is a some there's a consensus among scientists
that life conforms to a few rules. This is the
the generally agreed upon definition of life. It's carbon based.
Anything else is non living. You know, you look at
a piece of courts it's from silicon, I think not living.
(06:58):
Great example thinks it's programmed by DNA and RNA. Right,
so it has transcription of its genetic code, and that
is just it does not live without that. Those things
are built by amino acids and proteins. Those are the
basic building blocks of the organism. It's self replicating very important.
(07:24):
And then it also evolves according to Darwinian principles, which
is to say that the best properties and traits are
selected for over time. So if you put all those
things together, you have a pretty good idea about life.
But again, this is a really narrow definition, and if
you really kind of look at it, you're like, this
(07:45):
is there's a lot of room for other things to
function in a manner that's living that doesn't necessarily use
DNA or RNA, that doesn't use amino acids or at
the very least the amino acids that we use, and
it might not even be carbon based. Like maybe we
(08:05):
can broaden this a little bit, and that's the pursuit
of shadow biosphere.
Speaker 1 (08:09):
Yeah, and Carol Cleland was right in the money said
she wrote a book. It's really a paper, but you know,
she could bind it like a book, probably sell it
in a store, sure, But it was called the Possibility
of Alternative Alternative Microbial Life on Earth. We're also going to,
you know, talk a little bit about looking on other planets,
because we've talked a lot about that and suffice to say,
(08:32):
when we're looking for life on other planets where you know,
we're always looking for like an earth like place where
something like life as we know it could exist kind
of in the same way. But she was like, this
stuff might be right under our noses, everybody right, And
here's a paper about it, and I think it was
pretty smart paper. There was a should we talk about
the central dogma?
Speaker 2 (08:53):
I guess yeah, I think we need to.
Speaker 1 (08:55):
Yeah. So you know, you went over what life on
Earth contained, but the central dogma is a little more specific.
It was first proposed by Francis Crick in the nineteen fifties.
That is that DNA, the nucleic acid that we know
and love, has instructions for building all the proteins that
are required for something to be alive. You also have RNA,
(09:19):
which copies those instructions to take them to the ribosomes,
which also exists. Because that reads that RNA and assembles everything,
all those amino acids to make each protein, and bada
bing bada boom, you have life.
Speaker 2 (09:33):
Right, And so you take that process and you end
up with what's called the origin of life, the genesis
of life here on Earth.
Speaker 1 (09:43):
Genesis.
Speaker 2 (09:44):
We've talked about that. That's the scientific way of.
Speaker 1 (09:46):
Saying, well, okay, we go put on my lab coat.
Speaker 2 (09:51):
We've talked about this before multiple times. Remember we did
an episode on panspermia. We've done a bunch of episodes
that I think this primordial soup came up. And that's
the whole idea that either in some shallow tidal pool
or you know, some warm part of the ocean or
some body of water, there was a bunch of those
(10:13):
basic building blocks of life, amino acids, proteins floating around
and that somehow a self replicating process got kickstarted. And
the self replicating process is considered what's called a privileged function,
This idea that this mechanism for creating life was present
(10:34):
at the outset and is still around today, so we
self replicate. A couple others were metabolism, that's another suggestion
for the privileged function that kickstarted life. Or then compartmentalization
like having something to hold all of these processes in
like a bag of guts. Basically, so one of those
they say is what was responsible for kickstarting this process
(10:57):
of life, and that somehow, some a bunch of chemical
reactions started a chain reaction that became self sustaining that
eventually turned into increasingly complex processes, organelles, and eventually living organisms.
That's how life developed. That's the idea behind the primordial
(11:18):
soup that the central dogmas based on that's right.
Speaker 1 (11:22):
But in Cleveland's paper, she was like, well, hold on
a second, that's great, what a story. We love it,
we all believe it. But what if this happened like
more than one time. What if it happened multiple times
right here on Earth there were just different conditions in
different places, different chemicals came together. And what if that
happened and these are the shadow microbes? And what if
(11:45):
this stuff is still there? And the reason that we
haven't found it is because we're looking for again for
life that we understand as being alive and the ramifications
that would have not only to find stuff like that
here on Earth, but you know this idea that when
we go out and look in outer space for life
on other planets again we're looking for earthlike, you know,
(12:08):
atmospheres and Earth like conditions. She was like, well, what
if we're looking on the entirely wrong planets. There could
be stuff that's alive because we're just not looking in
the right places because we have such a narrow definition.
Speaker 2 (12:21):
Yeah, and we definitely have found increasingly extremophile organisms, like
for a long time we thought that organisms couldn't survive
past one hundred and twenty something degrees farenheight. Then we
found some extremophiles that can survive around hydro thermal events
that are as hot as two hundred and twelve degrees farentheight. Like, okay,
(12:43):
that's pretty awesome, but it's still life as we know it,
you know, like they're crazy in their adaptation, but they
still function according to the properties of life as we
know it. What Carol Cleland and others are saying is like, Okay,
we'll keep looking in even more extreme and vironments and
eventually you may find something that has had to adapt
(13:04):
to such an extreme environment. It uses different processes or
different raw materials that life as we know it could
not possibly use. And there you have your first shadow
bio organism.
Speaker 1 (13:19):
I think we should pick a great rest here. Rest.
Speaker 2 (13:24):
We'll be back everybody after this rest.
Speaker 1 (13:56):
And lo, the podcasters rested low and then on day
two they got on with the show. We should mention,
by the way, we did a pretty good episode on extremophiles, yeah,
a while back, So just if you haven't heard it,
you should just look up on the search engine of
your choice extremophile so if you should know, pretty neat.
(14:16):
But back to the shadow biosphere. You know, we mentioned
the fact that you know, Carol Cleveland's beating that drum, saying,
what if it's not something that we recognize because we
just don't recognize it as life as we know it.
And then she started digging in and she was like,
here's the thing. DNA and RNA aren't the only building
blocks of life. In theory. They are made of base
(14:40):
pairs of nucleic acids. For DNA, it's a D nine
cyanine quinine, and thymine. For RNA it's thymine that is
swapped out for ucell. But there are other three are
the same, but there are more nucleic I believe there's
six more nucleic acids that exists exist in nature. So
(15:02):
you know, why are we not even considering the fact
that those could be a part of life in a
way that we don't fully understand.
Speaker 2 (15:09):
Right, And first, ursill sounds like over the counter urinary
tract infection treatment totally does. Secondly, I could not, for
the life of me and I really looked find what
the other six nucleic acids are. I can't find it, Chuck.
But in that search I did come across something called
(15:29):
the hatch emoji DNA, which is those four at, which
is always together in GC, which are always together to
form those base pair nucleotides that eventually build up into DNA.
And they added p z B and.
Speaker 1 (15:46):
S and let's see them right.
Speaker 2 (15:48):
Well, that's four, so there's still two many. But the
really interesting thing that they found is that if you take,
if you rearrange say the original four bay pairs, or
you add these other brand new four base pairs and
run them through a ribosome, the ribosome, if you arrange
(16:09):
it correctly, and they're made of nucleic acids, the ribosome
will be like, okay, I'm transcribing this, So it's entirely possible.
They proved that it's possible that life could have evolved
separately from us by using different amino acids but similar mechanisms.
So maybe we are or could be, in this sense
(16:32):
distantly related to them, like maybe in the primordial soup,
but it branched off so early that for all intents
and purposes, it's non living life as far as our
definition of life goes.
Speaker 1 (16:44):
Yeah, well, nice job finding four of those six letters.
At least, let's just call the other two FU.
Speaker 2 (16:52):
Science.
Speaker 1 (16:53):
Yeah, so that's how DNA and RNA could be you know,
different as we know it. The same thing is true
for amino acids. All the proteins are built from the
same combination of twenty amino acids, because when Earth formed,
those were the twenty amino acids that, in a Darwinian sense,
(17:14):
were most successful making proteins that survived when life emerged.
There are five hundred we're not gonna name them, five
hundred other amino acids, or more than five hundred amino
acids on Earth. So yeah, totally. So it's just the
fact that Earth started when it did that those particular
twenty amino acids were the ones that were good at
(17:34):
doing what needed to be done to make things that
survived here. But it could have been, you know, at
a different time. It could have been any other combination
of amino acids, and they're.
Speaker 2 (17:43):
Still out there exactly. So a lot of scientists are like, well,
that just goes to show you that life as we
know it is the only kind of life. If we're
using the same twenty amino acids and there's all these
others out there, these are the ones that got selected
for These are the ones that worked in the primordial
soup and caroclelans forward again with her index finger raised
and says, Okay, I can see where you're coming from.
(18:06):
But again, as I said before, if life emerged in
other places, in other situations, under other conditions, in the
primordial soup, it's entirely possible that completely different combinations of
the other kinds of amino acids were the most usable,
and we're selected for that. And again, this is how
the shadow of biosphere could have started. And another petri
(18:28):
dish got dropped. And these guys are starting to second
guess undermining Carol Cleland, or even attempting to because she
just keeps facing them over again.
Speaker 1 (18:39):
Yeah, and they're like, well, how would that have happened
or how could that happen? She said, I don't know.
How about a meteor sucker because meteorites have fallen to
the Earth and asteroids that basically plant stuff on Earth
that come from another place. There have been meteorites that
have fallen that are carrying up to eighty other amino acids.
(18:59):
And her whole theory is it like, what if this
has happened, and maybe it's happened repeatedly, and again we
just don't know about it because we're not looking correctly, right.
Speaker 2 (19:11):
So, yeah, the panspermia episode that was the basis of it,
that Earth got seated with the necessary ingredients for life
from space. Right, that's right. So there's another peculiar aspect
of life as we know it that doesn't really make
sense to us, and I don't fully get how it
would tie into the shadow biosphere. So if you do,
(19:34):
let me know. But the best I can understand is
that because we don't know it, and because it's like
it just seems like a random, arbitrary development in life
as we know it, that it suggests things could go
the other way and maybe they have elsewhere on Earth.
Is that how you read it too?
Speaker 1 (19:54):
Yeah? I think so. Okay, just like an example of like,
see this can happen.
Speaker 2 (19:58):
Right, Okay, good, That's what I'm taking as too. And
we're talking about chirality, and chiralness is handedness and Greek
you're either right handed or you're left handed, or you
could be ambidextrous. But that's neither hum nor there. When
we're talking about cellular biology or molecular science, which is
what this pertains to, and if you make a bunch
(20:21):
of sugars or a bunch of amino acids in the lab.
Some are going to be left handed and some are
going to be right handed. But as far as life
on Earth is concerned, only left handed amino acids and
only right handed sugars can be useful as the building
blocks of life. So there's right handed amino acids and
(20:44):
left handed sugars, but they are completely useless to us
because all life on Earth only uses left handed amino
acids and only uses right handed sugars. And we just
don't know why.
Speaker 1 (20:58):
Yeah, and if this sounds like, all right, guys, what
are you talking about here with these hands, it's not hands,
it's the direction that their atoms are oriented. Yeah, they
talk about it in terms of handedness. I think just
as a well, I hate to say it is a shorthand.
So dumb humans like us can understand what they're talking
about at least halfway right.
Speaker 2 (21:19):
And so, because there's left handed and right handed amino acids,
they are mirror images of one another. They're constructed the
exact same way. They're constructed with the exact same components
to make up these molecules, but they are mirror images.
So if you overlay them, they're not twins mirror images.
So in exactly the same way. If you hold your
(21:42):
hands out in front of you, palms down so the
tops up, and you just kind of hold one over
the other, they're not twins. They're mirror images of one another.
And that's exactly true with amino acids and sugars. They
each have a mirror image. And again, only one kind
is useful to life. The other ones just get spit out.
So what if, again, under different conditions, at some point
(22:05):
in the past, there were organisms that learned to use
the other kind left handed sugars and right handed amino acids,
that would certainly qualify as a shadow biosphere bioorganism.
Speaker 1 (22:20):
Yeah, and we have synthesized these in labs. But what's
the deal. What I don't understand. If they were able
to synthesize it, that means that it did already exist,
but it just isn't anything that was alive.
Speaker 2 (22:35):
Yeah, I don't know exactly what they did. They built
a cell that uses right handed sumino acids. Yeah, yeah,
and they I don't know if it was living or not.
I don't think it was living or else they would
be like we created artificial life here. I don't think
anyone's ever done that. I think they just created the
(22:56):
structure of it. Like if there if there was something
like a cell that use that kind of stuff, this
is what it would be structured as. The whole reason
they built it was to try to attract things like
chiro viruses that function using the opposite stuff that we
use for life. It was a honeytrap, is the way
that they put it.
Speaker 1 (23:15):
Like they take it out to a club and set
it on a bar table and they're like, hello, everybody,
exactly right.
Speaker 2 (23:21):
So nothing came along and took the bait, But that
doesn't mean it's not there. The better argument against things
like that living, if you asked me that I ran across,
is that if you did have something like that that
could consume other things, it would have no natural predators.
It would it would not be able to be infected
(23:43):
by any of the known viruses we have. It would
be unstoppable, and it would replicate in such an unchecked
manner that it would apocalyptically destroy the food web based
on whatever, you know, one microbe that it feasted on.
And because that's not happen, and there's a pretty good
chance that there's no such thing as that.
Speaker 1 (24:04):
Yeah, I guess now we can talk a little bit
about the last universal common ancestor or the LUCA, which
is the idea that all life on Earth can be
traced back to this very first functioning cell that started
the whole party. If we believe in something like the
shadow biosphere, there can still be a last universal common ancestor,
(24:25):
I think in terms of what created our life. But
we have to consider the fact that there were multiple
genesis that happened at a certain point and you know,
maybe they just didn't evolve because you know, part of
that opening four things that we talked about was that
things evolved in a sort of the Darwinian sense that
(24:45):
we recognize. But the idea of the shadows biospheres, maybe
these things did occur at various sort of calm periods
on Earth where there weren't you know, ice ages, or
it wasn't being bombarded by asteroids, and that there's still
they just never evolved. They're just sort of trapped.
Speaker 2 (25:02):
Yeah, that's one example. There's another explanation that they might
be in places we haven't explored yet, so like there
could be you know, life on the surface of Earth
and then we find microbes all the way down to
some you know level and it gets too hot for them,
and then it's a dead zone. Well maybe beyond the
dead zone there's these you know, shadow biosphere organisms. And
(25:23):
then another argument I saw against the idea. So a
lot of scientists are like, sure, it's entirely possible there
were different origins of life, but the other one sputtered out,
only ours continued on a lot of that's not a
very controversial idea. What's controversial is that it didn't sputter out,
that they just evolved and we share Earth with them, right,
(25:44):
But a lot of the arguments against that state that, Okay,
well maybe it did make it beyond the sputtering stage,
and it was you know, we shared the primordial soup
with it, but it got absorbed into us and now
it's a part of us, but you know, not really anymore.
And that misses the point because what they're talking about
(26:05):
is lateral gene transfer, where like say one cell just
takes over another cell and they share DNA from that
point on. That's totally missing the point. Like that would
not be a shadow organism, it'd be an early additional
ancestor to us. This is stuff that we couldn't possibly have,
you know, mixed with to become us or else it
(26:27):
wouldn't be a shadow bio organism. It would just be
another component that created life as we know.
Speaker 1 (26:34):
Would That's right, And lateral gene transfer was totally an
a cappella skiking group from the seventies, a gospel group, oh,
led by a guy named Gene Nice.
Speaker 2 (26:44):
Nice.
Speaker 1 (26:44):
Yeah, I've got the record. It's not even a joke.
Speaker 2 (26:48):
Are you kidding? You're not kidding? Ah, wow, you did
get me. That was finally, Well, we're pretty wacky, so.
Speaker 1 (26:58):
Oh goodness. It is a meal, best serve cold.
Speaker 2 (27:01):
Do you do you want to take a break and
savor that for a little while.
Speaker 1 (27:04):
Uh yeah, sure, let's go ahead and take a break.
I'm going to take another nap and dream about getting
Josh and then we'll be right.
Speaker 2 (27:12):
Back, all right, Chuck. So we said that, or I
(27:44):
should say, you said at the outset that nobody's looking
for you know, some silicon were wolf or something so great.
So instead there were we're looking for my crubs. And
the reason that everybody agrees if there is a shadow
by its microbial life is a couple of reasons. One
(28:04):
we could look at a microbe and look right past it.
They don't have faces, they don't have tails, they don't
have hair, they don't really have any features that would
really stand out just visually. We have to really examine
them to find the differences that we would be looking for.
And then on top of that, we've only cultured and
described less than one percent of all of the estimated
(28:25):
species of microbes on Earth, right so we have very
little understanding in the big picture of the microbial life
we share Earth with. So it's entirely possible we just
haven't stumbled upon one yet. But that doesn't mean it's
not there in that other ninety nine percent of the
kinds of microbes on Earth with us right.
Speaker 1 (28:44):
Now, Yeah, for sure. And you know we've kind of
walked around this very plain statement. But the plain statement
is look where we think or look where we so
far think that nothing here can live, because that might
be a great place to start, you know, if we're like,
nothing can live in the dead sea micro organisms, because
(29:06):
it's just it's so full of saline that we just
know nothing could live, Like, well, maybe start there, or
you mentioned earlier the fact that things we didn't think
anything could sustain life greater than like one hundred and
twenty two degrees fahrenheit. But then we discovered colonies of
bacteria that could. We're like, well, that's evidence right there
(29:27):
that maybe we should look in like really really hot places,
really really cold places, really acidic places, really base places.
Anything on the list that says human life can't exist there,
maybe start looking there.
Speaker 2 (29:40):
What's crazy is when we have looked there, we keep
finding stuff that can exist, like life that yeah, doing
just fine there that just should not be there. The
best example I found are types of I think slime
mold maybe or algae that it lives in abandoned uranium
(30:02):
minds so this place is so crazy radioactive, No life
should be able to survive there, and yet they think
these things are actually taking that radiation and using it
as chemical energy. And then there's also a kind of
single cellular life that they found growing in one of
the abandoned chernobyl reactors. Again should not be aware because
(30:25):
of the radioactivity. But these things still conform to the
basic principles of life as we know it. The point is, though,
is you just keep thinking in more and more extremes,
and you know, maybe we'll find it like the upper
atmosphere is the one that suggested because no life's supposed
to be able to live up there because of the
(30:45):
cosmic rays and the temperature and all that stuff. It's
just not a pleasant place to live from what I understand.
And then other people are like, Okay, if we keep
looking and in these more extreme environments and we're just
finding life as we know it, maybe we should look
around and see if we find anything weird in places
(31:05):
like right under our very noses. And one of the
big ones that has been touted is desert varnish. And
this one, from what I can tell, is still the
jury's out whether it's a shadow bio organism.
Speaker 1 (31:20):
Yeah or not or not. You're hanging out there like
a chad. So yeah, if you've ever been out to
the desert in the United States, if you've ever driven
around like Utah or Arizona, maybe even Colorado, maybe New Mexico,
you might have been driving along and seeing like a
(31:41):
very sheer sort of cliff face, and within that cliff
face you might be like, oh, that's just weird, sort
of shiny, dark area of it. There are always really
arid environments. Indigenous peoples used to create petroglyphs, so instead
of like you know, writing on something, they would scrape
away that varnish to make their art for the original
(32:04):
lighter colored earth underneath it. But I mean, I've seen
these things in person. I've driven by it, and I
didn't know what it was. I just figured it was
dark rock or something. But it's called desert varnish, and
scientists have been fascinated for a long long time. One
reason is because it grows about the pace of a
width of the human hair every millennium, and because that
(32:27):
happens so slowly, they were like, well, this is just
a geological process that's going on, maybe the sun hitting it,
some sort of chemical reaction takes place. But they found
that that's it's actually a living thing, right.
Speaker 2 (32:42):
They don't know there's no geochemical process that accounts for it.
There's no biological process that accounts for it. They just
don't know. It's largely manganese in nature. But the problem
is it's not drawing manganese out of the rock, like
a lot of these rocks don't have any manganese or
have such trace amounts that it certainly wouldn't account for
this desert varnished. So they just don't know how this
(33:07):
stuff is growing or what it is. But it's probably
the greatest contender right now for a shadow organism from
what I can tell. Like they're like, well, then it
must be a geochemical process. We just don't understand. And
it's like, maybe what you're calling geochemical is actually life
in a different manner.
Speaker 1 (33:26):
Yeah, I guess there's just said the theory that it's
alive that is biochemical.
Speaker 2 (33:30):
Yeah. There was also one that was like we founded everybody,
we found the shadow organism and it went downhill from
there back in twenty ten.
Speaker 1 (33:40):
Yeah, that was gfag dash one that is a bacterium
that was found in Mono Lake, California, And they were like, well,
this bacterium is really weird because it doesn't it's not
sort of playing by the rules that we understand. Because
if you're going to be a living thing to make
DNA and RNA, you need phosphorus, and it doesn't look
(34:02):
like this thing is using phosphorus. It looks like it's
using arsenic, which would be a huge, huge mind And
so they thought GFA j dash one, you're you're the dude,
And everyone was really hot on this idea, and then
they did follow up experiments and very sadly found out
that it used very very very small amounts of phosphorus
(34:25):
and it just wasn't instantly evident. So they're like, all right,
just another extremophile. That's that we understand.
Speaker 2 (34:33):
Yeah, now we know.
Speaker 1 (34:34):
So cool.
Speaker 2 (34:35):
That's another benefit of it, Like we're finding stuff because
we're out looking for shadow life. We're finding other life
still too, So that's I mean, it's not like they're like, oh,
another extra file. It's never been seen in the history
of humanity.
Speaker 1 (34:49):
Just juke it.
Speaker 2 (34:50):
That's an interesting way that you pronounced that. I've been
in my head pronouncing it gufage, you know. So okay,
let's move on. Let's move on to life with the
y chuck, because I think that that's a good next
(35:12):
place to start.
Speaker 1 (35:13):
Yeah, there's a guy. Well here's the idea, is that, like, hey,
maybe there is just we should just accept the idea
that l i f E isn't all we think it is,
and maybe it's broader than that and maybe or maybe
we just need another definition l y f E. And
I think that was put forward by an astrobiologist named
(35:33):
Stuart Barleot not Bartlett, just Barlatch, And he said, well,
maybe that is the l y f E definition is
just any system and this is a quote any system
that fulfills all four processes of the living state, namely dissipation,
auto catalysis, catalysis either one, catalysis, homeostasis, and learning.
Speaker 2 (35:58):
Yeah, so just to get into it real quick, dissipation
means that it dissipates energy or something like waste brought
byproducts like heat. That's a big one. Or else it'll
overheat and die, or it will never poop out its
food and will die from that. That's it's just a
really easily overlooked component of something organism that can keep going. Also,
(36:22):
it needs to be able to make more copies of itself.
That's that auto calysis, catalysis, auto catalysis, Sure, that's that's
important because what it's doing is it's creating a process
that creates another version of itself and also a product
that triggers that process over again, so it can just
(36:43):
keep going. It also has to be able to maintain homeostasis,
so it can't just go totally haywire anytime you know,
somebody nearby coughs. And then lastly, it's got to be
able to record information about the environment like this is
how you keep from going haywire when somebody coughs, and
it can be encoded in some way, shape or form,
(37:06):
so it can be passed on to the replicants of itself. Yeah,
that's life with a why. And I think that's exactly
the kind of broadened definition that we need. And the
other thing about life with a why, that includes life
with an eye, like life as we know it, and
(37:26):
just saying life with an eye is so much less
clunky than life as we know it, and it falls
under a larger umbrella. So it's a broader definition that
includes life as we know it, but also potentially includes
members of the shadow biosphere as well.
Speaker 1 (37:41):
Yeah, and what this potentially means is if there is
life with a why here or elsewhere, that means that
kind of anything is possible. It doesn't mean that, hey,
there's intelligent life out there, but it doesn't mean there's not.
I mean it would certainly kind of interest toward that idea.
In a very real way, we found that there is
a different kind of life we just never understood before
(38:04):
here or elsewhere. There's an astrophysicist named Paul Davies really
smart guy obviously who has done a lot of scholarship
work about intelligent life elsewhere, and he talks about timing
a lot, like, you know, Earth happened the way it did,
and it's kind of like what we touched on earlier.
(38:24):
Earth happened the way it did because of the timing
of it all. We've been around for about four and
a half billion years, and we won't be around in
about a billion years, Like the Earth will be scorched
basically by the Sun, and it was just sort of
cosmic luck that everything evolves when it did as it did,
because there's a kind of a short window in the
(38:46):
grand scheme of things between when something starts happening and
being able to get to the point where you have
like intelligent life like human beings and the planet being
scorched or being blasted away by a large Yeah.
Speaker 2 (39:00):
So Paul Davies's argument kind of suggests that life is
probably pretty rare, if not singular, like the only we
do know that life emerged once in the entire universe
that led to us in all life as we know it,
but that's it. We don't know that life emerged anywhere
else any other time, including on Earth. And that's one
(39:22):
of the things that would make detecting a shadow biosphere
so amazing, is it would it would essentially immediately say
the universe is teeming with life. If life developed two
different ways on the same planet. That strongly suggests that
not only is there life elsewhere in the universe, but
(39:42):
that biology is as immutable a cosmic or universal law
as physics or chemistry. Right that if you have even
just a few components put together that that gives rise
to life, biology is going to take over and life will.
That's ultimately the most exciting thing that gets scientists jazzed
(40:05):
about looking for the shadow biospheres. What the implications that
we'll have about us sharing life elsewhere in the universe.
Speaker 1 (40:13):
Yeah, totally pretty cool stuff.
Speaker 2 (40:15):
Huh Yeah, I like it, Chuck, I'm glad that we
did this. Thanks for doing it with me.
Speaker 1 (40:21):
It was fun. We got through it.
Speaker 2 (40:22):
Yeah, we did well. Since we got through it, everybody,
that means it's time for listener. Mayo.
Speaker 1 (40:30):
I'm gonna just read this one from Joel because it's
kind of just a fun little little ditty. Hey, guys,
I guess it's not a diddy. It's a story. First off.
I want to say thanks for all the work you
do to create an enjoyable and informative listening experience. I've
been a casual listener since twenty eighteen, and your show
has positively redirected the course of my day or staved
(40:50):
off boredom through long winter nights. Because I live on
Salt Spring Island, BC, off the coast of Vancouver Island
and work at a golf course there. Today I was
mowing the fairways on a wet and dreary morning. I
put on the Manson Murders podcast and relax into my work.
Part Way through, Dennis Wilson came into the story and
Chuck mentioned his solo album. I think it's called Pacific
(41:14):
Ocean Blue.
Speaker 2 (41:14):
Maybe I don't know.
Speaker 1 (41:16):
I think so great record. Feeling a little low, I
decided to pause the podcast and listen to the full album.
I listened to all the songs as I continued my
mo lines. Truly a wonderfully enjoyable album. Thank you for
that excursion into the music. Once the album finished, I
listened to the mower for a few minutes and then
resumed the podcast. And the first words I hear are
(41:37):
Chuck saying Eventually they leave Dennis Wilson's house and I
chuckled as I genuinely felt I had just been in
his house myself.
Speaker 2 (41:45):
Nate.
Speaker 1 (41:46):
Anyway, short little story for me. Thank you for the
years of entertainment. Keep up the great work that is
from Joel. And Joel sent a picture of that fairway
mode while listening to Pacific Ocean Blue and Joel as
a beautiful golf course and I would love to play
it one day.
Speaker 2 (42:03):
Oh, very nice. Yeah you're a golfer. I forget that
sometimes I am.
Speaker 1 (42:06):
I'm not very good, but I enjoy putting the phone
away for five hours and walking around with my buddies
in the sunshine.
Speaker 2 (42:12):
Very nice. Well, thanks a lot, Joel, much appreciated. We
love stories like that, And if you want to be
like Joel, send us an email. Send it off to
stuff podcast at iHeartRadio dot com.
Speaker 1 (42:26):
Stuff you Should Know is a production of iHeartRadio. For
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