Can humans survive interstellar travel?

Daniel and Kelly talk about how to keep humans healthy and happy during interstellar voyages. 

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Episode Transcript

Speaker 1 (00:05):
Imagine a future one hundred maybe two hundred years from now.
In space, manufacturing has come a long way, and we
can now build colossal structures using resources collected from the
Moon and the asteroids. First interstellar ship has been built
and is getting loaded up with supplies for a long
trip to Alpha Centauri. It's now time to pick the

(00:27):
crew who will be the ambassadors for humanity should we
meet intelligent life in the neighboring Solar System. How many
people will we send, how should we pick them, What
dangers will they face en root and what will their
lives be like during this journey. In our last episode,
we talked about the rockets that could carry us to
distant stars. Today, we're going to talk about the squishier

(00:49):
side of things, focusing on some of the human stuff
you'd have to deal with on an interstellar journey. Welcome
to Daniel and Kelly's Extraordinary Universe. Hi.

Speaker 2 (01:12):
I'm Daniel. I'm a particle physicist and the longest flight
I've ever taken was fourteen hours.

Speaker 1 (01:18):
Hi. I'm Kelly Wiiner Smith. I studied parasites in space,
and I think the longest flight I've taken was twelve
I've been down to Brazil. I haven't really kept track
of how long my flights were. Where were you going?

Speaker 2 (01:29):
I went to an absolutely ridiculous slash amazing boondoggle conference
in Fiji on the island of Morea, where the University
of California has a research station, and we were there
to talk about dark matter, of course, So I brought
my daughter and we did a lot of snorkeling and hiking,
and we rode horseback of the mountains and tried to
keep the horses from eating pineapple plants. And it was

(01:51):
an amazing time. But wow, the flight was long.

Speaker 1 (01:54):
What made it a boondoggle?

Speaker 2 (01:56):
Why do you need to go to a tropical island
to talk about dark matter?

Speaker 1 (02:00):
Don't That's what makes it a Yeah, I gotta be honest.
Ecology has a lot of that too. It's like, why
do you need to go to the glorious rainforest to
answer questions about frogs when you've got frogs in the US.
But I get it. We like go into beautiful places.

Speaker 2 (02:14):
Yeah, it's one of the perks of being a scientist
is getting to travel to weird, random places to meet
with your colleagues.

Speaker 1 (02:21):
That's true, that's true. I love getting to see new places.
I often get invited to places that I never actually
really wanted to go to, but once I get invited,
I'm like, yeah, I want to go to Slovakia, and
I love Slovakia. Broadoslava was beautiful.

Speaker 2 (02:34):
Well what's your experience like on these long flights, because
I always feel like, oh, fourteen hours, no big deal.
I'll just watch a few movies and then like two
movies in, I'm like, wow, get me off this plane,
and then like four movies in I'm gonna kill myself.
And then by the time I land, I'm like, hmm,
that wasn't so bad.

Speaker 1 (02:52):
I hate it. I have a very similar experience. I
can't sleep. I try to sleep, I can't sleep. I'm
not comfortable. Every once in a while, I'll get lucky
and there'll be no one else in the row and
I can just like lay down and at least then
I feel kind of rest ish or restoids. I know,
I hate it too, And then I always feel kind
of angry at the people in first class because they've

(03:14):
got like a much nicer setup. But you know, what
are you gonna do.

Speaker 2 (03:18):
You're not gonna spend ten thousand dollars for that flight,
that's right. Yeah, no, But if I was an astronaut
and I was going to the Moon or to Mars
or to Alpha Centauri, I might want the engineers to
build in a seat that can fully recline. What do
you think?

Speaker 1 (03:33):
Heck, yes, you do have to have a completely different
mindset to really enjoy super long trips. Like Jim Lovell
and Frank Borman were on a Gemini trip around the
Earth and I think they were up there for something
like two weeks, and it was a really tiny space
and at least on airplanes, like, yeah, the bathroom is small,
it's super inconvenient. I hate it. But it's got a
door and the Gemini didn't. And so Frank Borman tried

(03:57):
to go all twelve days without having a bowel movement,
and I think he made it like eight days or something,
and then he was like, Jim, I can't wait anymore.

Speaker 2 (04:06):
I'm about to make a delivery.

Speaker 1 (04:07):
Oh gosh. Yeah, So anyway, it could be worse.

Speaker 2 (04:10):
So you're saying that the cutting edge super distant travel
is less convenient and less comfortable than like economy flights
across the country. That doesn't make any sense to me.

Speaker 1 (04:19):
Well, you know, you've got to pay for all of
the space that you send up there, and it's super expensive.
And I mean, let's be honest, anybody who's told you
get to go to space is going to put up
with whatever you give them, and so they're definitely going
to go. But there was a recent SpaceX trip where
there were complaints about the bathroom also, and I think
it was the Dragon capsule. Restrooms in space are just
hard to pull off.

Speaker 2 (04:38):
Well, I think this is another case of like my
over optimistic rose colored glasses when it comes to space travel,
imagining that the problems we have with like airplane flights
are not going to be even worse on space trips.
They're somehow all going to be comfortable and get along
and the food is going to be amazing like it
is on Star Trek. Right. That's why I was excited
that today we're going to dig into like the reality

(05:00):
of a potential interstellar trip. What's it going to be like?
Will there be doors on the bathrooms? How far back
will this eat recline? And will they have anything besides
peanuts and pretzels?

Speaker 1 (05:10):
Well, let's dig in and find out. So this is
part two of our interstellar travel series. We talked about
the kinds of rockets that get you to space in
the last episode, and today we're talking about the squishy
human side of things, and so we asked our listeners,
can humans survive interstellar travel? Why or why not. Here's
what they had to say. Humans could survive interstellar travel

(05:33):
with terraform spaceships, and over multiple generations, they could get
somewhere interesting.

Speaker 3 (05:40):
There are so many unknown issues with closed ecosystems in
order to produce the food that we need in the
form of plants, et cetera, that I'm too sure that
we've solved all the problems necessary in order to have
a long duration interstellar travel with.

Speaker 4 (05:58):
Our current technology. I don't think it's possible, but maybe
with advances in propulsion and radiation shielding and artificial gravity
from propulsion, that might be possible.

Speaker 5 (06:11):
One human couldn't survive because we haven't sought in suspended
animation yet. But if you're talking about generations of humans,
if as human we've sorted all the problems of sustaining
reproduction and nutrition and health, I wonder whether the risks
of the dangers posed by cosmic rays will actually be

(06:32):
less in deep space. We do only then have to
worry about the problem of re entry into the new
stellar system.

Speaker 6 (06:41):
I think generally it's possible, but you have the problem
that when you go fast you have cosmic rays that
are really high energy, and if you go slow, it
takes forever. So it's a tradeoff and you're lose in
both situations.

Speaker 7 (06:54):
It depends on how far away the other stars. If
the star we're trying to get to is there one
that we're going to share our clouds with in about
a million years or so, then that's much more achievable
than a star on the other side of our galaxy.

Speaker 8 (07:07):
I say no because the first two mens who leave
Earth going to interstellar space will not be alive because
it takes approximately twenty two to twenty five thousand years
to exit our solar system. And that opens up the
question about children in space to continue to journey, because
the adults who begin the journey will not live to
exit our solar system.

Speaker 9 (07:22):
So no, if we allow for human reproduction all root,
which is a big if, humans would encounter significant survival challenges,
not the least which is that our physiology is ill
equipped to handle zero gravity and excessive radiation exposure in
the vein of we do not know what we do
not know. There are likely other factors that terrustrial living
either provides for us or protects us from that we

(07:43):
would faithfully and tragically encounter on the interstellar voyage.

Speaker 10 (07:48):
We can imagine traveling to other solar systems, but can
we deal with all the questions radiation, food, power sources, generationships.
We just don't know enough at this point.

Speaker 2 (08:00):
Those are super fun answers, And if you find yourself
speaking back to the podcast with your own answers, then
send us those answers and we'll put them on the
pod so that everyone else can hear what you have
to say. Just write to us to questions at Danielankelly
dot org and we will share your insights with the world.

Speaker 1 (08:18):
Looking forward to hearing from you. And we've been very
excited to have more women sharing their responses lately, so
let's keep that up. Go women.

Speaker 2 (08:25):
Well, do you think our listeners also have rose colored
glasses and they're underestimating the difficulty of traveling to space
or do you think they have a realistic sense.

Speaker 1 (08:33):
We have a really nice range of people who are
super optimistic, and I would maybe say not quite reasonably so,
and then people who are maybe a bit more down
on the enterprise than is necessary. We've got a lot
of variability. I think it depends a lot on the
timeframe that you're willing to consider for this question.

Speaker 2 (08:50):
All right, well, let's dig into the problem why space
travel is so much harder than airplane trips, or if
it's just airplane trips times a thousand, tell us what
basically are the obstacles here to traveling in safety and
comfort to another solar system.

Speaker 1 (09:05):
Well, as you pointed out in the last episode, space
is vast, and so if we're going to Alpha Centauri,
that is four light years away. So with current technologies,
we're talking about eighty thousand years. That's a lot of
human generations.

Speaker 2 (09:18):
That's a lot of movies to watch.

Speaker 1 (09:20):
Wow, oh my gosh. Yeah, maybe in the next one
hundred years Marvel will make enough movies to get you
to Alpha Centauri.

Speaker 2 (09:26):
I think there might be enough fast and furious movies
to make sure.

Speaker 1 (09:30):
I would not make it to Alpha Centauri fast and
furious movies. I would rather push myself out the airlock.

Speaker 2 (09:36):
But our he no, you're missing out, You're missing out.
Fast and furious is fantastic because they don't take themselves seriously.
Like every movie they have an even more ridiculous stunt.
They're like, oh yeah, how about a space shuttle. Okay,
how about a submarine on the ice with a torpedo.
It's ridiculous and fantastic and really creative. I watch a
lot of terrible movies, and there's always something new in

(09:57):
the Fast and Furius that makes me go, whoa that
it was cool. So yeah, don't overlook them.

Speaker 1 (10:02):
Okay, all right, I'll take another look at the Fast
and Furious series. I didn't imagine I would say that
phrase today, but there you go.

Speaker 2 (10:07):
But I don't think we want to travel the stars
fast and furious. I think it's kind of more like
slow and calm is the way to go.

Speaker 1 (10:13):
That's what I would like, and with no explosions or
anything like that. So you said that we could get
to Alpha Centauri in forty years if you can travel
at ten percent the speed of light. Yeah, So we're
going to talk about a range of different options. What
if you could get there fast if the technology works out,
and what if you need to get there over the
course of multiple generations. So you need to have a
generational ship sometimes called an arc and this field has

(10:35):
a good sense of humor, so sometimes they call the
study archaeology also, yeah, which I love.

Speaker 2 (10:43):
That is very cool.

Speaker 1 (10:45):
All right, So one human thing we're going to need
to overcome is this whole money situation because the cost
of a project like this is probably going to be
massively prohibitive. So you talked about how much mass would
be needed to hold the propellant, and that for chemical
rockets the tank would have to be as big as Jupiter.

Speaker 2 (11:03):
Yeah, and then you also need to somehow find that fuel.

Speaker 9 (11:05):
Yeah.

Speaker 2 (11:05):
Right, basically you have to use Jupiter as your rocket. Yeh.

Speaker 1 (11:08):
Many layers of problems here. But you know, if you're
talking about bringing humans that are awake, you're also going
to need space for recreation areas, space for schooling, space
for medical facilities, places to grow food. The International Space
Station is the most expensive human made object ever and
it's clocking in at about one hundred and fifty billion
dollars and it usually holds seven people uncomfortably.

Speaker 2 (11:30):
So this is going to cost a lot of money.
But we're basically just going to ignore the financial side
of the question.

Speaker 1 (11:35):
We are, yes, right, So let's assume that money is
no longer an object. Yea, yeah, hey, that's right. Humanity
has decided we absolutely must do this. Okay, what kind
of problems are the humans going to encounter? As you
might remember from our conversations on Mars and the Moon,
space has a lot of radiation that is bad for humans.
It has two kinds of radiation that are not very

(11:55):
common here on Earth, and that scalactic cosmic radiation and
solar particle events. And these are bad for equipment and
for people. And I'm kicking over to Daniel tell us
about galactic cosmic radiation and solar particle events.

Speaker 2 (12:09):
Yeah, so the Sun puts out a lot of light,
but it also shoots out a lot of other stuff.

Speaker 4 (12:14):
You know.

Speaker 2 (12:14):
They're protons, they're electrons. Basically, it's just spewing plasma. We
call this the solar wind, and it's moving at high speed.
So these particles are dangerous because any one of them
hits your body, tears through it like a little tiny bullet.
You can rip apart DNA, you can destroy cells. It's
not good. One random one you're probably fine, But you
take enough of these you're getting cancer. And down here

(12:36):
on the surface of the Earth. We don't worry about
this because while the solar wind is hitting the Earth,
the atmosphere protects us. It's an enormous, very thick, very
massive blanket. And the whole idea is that when you
go out into space, you no longer have that atmosphere,
so you have to replicate that with shielding. Galactic cosmic
rays are a whole other question. They're basically radiation from

(12:56):
other stuff in the galaxy, like the combined radiation from
other stars and from black holes and from other weird
stuff we've never even figured out, like there are particles
that are so high energy. There's nothing in the universe
we know of that can make particles go that fast,
and yet we see them. So there's like really fascinating
physics mysteries there. But from a human survival point of view,

(13:17):
you don't want these super duper high energy particles hitting you. Basically,
space is filled with tiny bullets, and you got to
go up there with a bulletproof vest.

Speaker 1 (13:25):
I am always so impressed by how eloquent you are
when I put you on the spot, Bravo. So we're
going to need to shield against this kind of stuff.
And it's not just a problem for human bodies, it's
also a problem for our machines. Did I tell the
story on the show before about Terry Vertz and Samantha
Christofferetti when the ISS had a false alarm?

Speaker 2 (13:42):
Oh? Tell us?

Speaker 1 (13:43):
All right, So you've got Terry and Samantha in space
on the International Space Station and an alarm starts going
off and Terry's not immediately sure what this alarm means,
but Samantha has memorized all the alarms and it's an
ammonia leak. And on the US side, ammonia is used
to cool the space station is also toxic. So the
protocol for what you do when there's an ammonia leak

(14:04):
as you run over to the Russian side, you close
the first hatch, you take off your clothes. You close
the second hatch with you on the other side, you take.

Speaker 2 (14:13):
Off your clothes. Why do you have to take off
your clothes as just make it more fun and dramatic.

Speaker 1 (14:17):
Well, yeah, I mean one, sure, but also that ammonia
could cling to your clothes and you don't want to
bring it over to the Russian side. So you got
to hope the Russians have some undies they'll be willing
to loan you, and so they ran over. They closed
the first hatch, but they didn't smell the ammonia. And
this is an important sort of lesson about how humans respond,
like it sort of doesn't matter what protocols you put
into place. When one human is looking at another human

(14:40):
and they're both like, am I going to really see
you naked? Right now? They decided to just skip that
step and they went in with all of their clothes
over to the Russian module. It did turn out it
was a false alarm, and the reason you go to
the Russian module is because they use glycol to cool
their side, which is not as toxic, and so if
the leak was coming from anywhere, it was the US
side anyway. It was later determined that the most likely

(15:03):
reason that this alarm got switched on was because the
computer had been hit with galactic cosmic radiation, which messed
with the equipment and started setting off alarms. You could
have cancer, cognitive declines, your machines could start breaking down.
So this is a problem we need to take seriously.

Speaker 2 (15:18):
Yeah, this is actually really fascinating from an engineering point
of view. You know, what's happening is that these particles
are passing through your equipment. Sensitive bits of it are
mostly made out of silicon, and when a high energy
particle passes through, it leaves a trail of ions, you know,
it like kicks electrons and leaves holes, and this is
how these things work also, right, they like separate the
holes and the electrons, and so all this equipment can

(15:40):
get like a false bit, like you can have a
zero in your memory and then they can turn into
a one or something, and so these kind of cosmic
ray bitflips are real concern and like massive data centers
worry about this also, but they have a lot of
error correction and so they have like duplications and cross
checking to basically remove this. So you can either have
a lot of duplication or you can try to make
get radiation hard by shielding it. The even folks who

(16:02):
are using diamonds instead of silicon, because diamond has a
lot of the same electrical properties, but it's radiation hard.
You can grow diamond, it's much more expensive and there's
not a huge industry for this. But like at the
large hadron collider, there's very intense radiation near all of
our sensitive detectors. So every couple of years, we've got
to pull it out and swap in a new one
because it's basically ruined.

Speaker 1 (16:23):
Wow.

Speaker 2 (16:23):
So, yeah, electronics are very sensitive to high levels of radiation.
And if you are relying on your electronics to keep
you alive and an eighty thousand year journey in all
of your grandkids and great grandkids, then yeah, you want
those things to work.

Speaker 1 (16:36):
Yeah. And so the shielding could come in the form
of things like water, like you could store your water
supply on the outside. Would that help with galctic cosmic
radiation too, Daniel.

Speaker 2 (16:45):
Yeah, with various kinds of it. Yeah, okay, but mostly
you basically just need high Z mass, like you need
atoms with a lot of protons and neutrons between you
and the radiation.

Speaker 1 (16:55):
Got it. I've also seen proposals for scraping the regolith
off the Moon and padding your interstellarship with it. That
would be complicated, but it's a solution.

Speaker 2 (17:03):
That would be pretty cool because then your ship looks
like a rock, you know, yeah, like floating through space,
like masquerading as an asteroid or something.

Speaker 1 (17:12):
Well, another complicated problem we're going to need to solve
is what do you do about no gravity.

Speaker 2 (17:16):
Right, But the takeaway from the shielding is an important one. Right.
It makes our ship big and massive and heavy, and
that makes it expensive. Right, But fortunately money is no
hurdle for.

Speaker 1 (17:25):
Us, so cool, that's right. In space manufacturing might help
with this a lot. So you know, you could, like
I mentioned, go get the regulis from the surface of
the Moon, but also you could go to the asteroids
and extract water from the asteroids. In that way, you
don't have to pay to boost it from Earth. But
one way or another, it's going to be an expensive,
massive project.

Speaker 2 (17:41):
Yeah, all right, So problem number one is radiation.

Speaker 1 (17:44):
Yes, and problem number two is going to make the
design of our vehicle even more complicated. And problem number
two is that there's no gravity in deep space. So
we know from astronauts on the International Space Station and
the space stations that came before that when they are
essentially in free fall and feeling the equivalent of no gravity,
that their bones start breaking down, their muscles start breaking down.

(18:04):
And the gravity on Earth and the fact that we're
constantly moving around and submitting our bones and muscles to gravity,
and then the pressure of our bodies as we run
around that makes our bones and muscles strong. That's like
a que Our bodies need to keep these things toned.
Without those cues, they just start to decay because you're
not using them, so bodies start falling apart. Additionally, we

(18:24):
see declines in vision, and we think that's because the
fluids in our bodies without gravity to pull them down,
sort of accumulate near our heads and change the shape
of our eyes. There's also some evidence that there could
be some cognitive declines. Basically, we're gonna want some gravity
when we're living out our lives on a ship, and folks.

Speaker 2 (18:42):
Out there might be thinking, well, you know, we're adapted
to life on Earth, but if we spend it long
enough in space, maybe our bodies are just going to adapt.
Maybe we don't need those bones and those muscles because hey,
we're all floating around to the Blue Danube anyway, right,
Why do we care about degradation of our bones and
our muscles if we're just floating in space.

Speaker 1 (19:00):
Yeah, so that's a great question. We don't actually know
that we could survive long term. So the longest anyone
has ever been in space, I think, is four hundred
and thirty seven days. That was Valeri Polyi call. So
we don't even have like more than a year and
a half of consecutive time in space. We know that
astronauts lose something like one percent of the density of
their hip bone per month, and we don't know if

(19:22):
that tapers off eventually. But if you imagine trying to
have babies in space, hold.

Speaker 2 (19:26):
On, wait, I'm gonna imagine it. Hold on. Hmmm, yeah
that seems gooey.

Speaker 1 (19:30):
Yeah, yeah, that is such a dive response. The gooeyness
is not a problem.

Speaker 2 (19:34):
Man, But now you're in space, you have like weird
balls of goo.

Speaker 1 (19:36):
It's oh, imagine trying to do a C section in
space with like the blood floating around your head anyway unpleasants.

Speaker 2 (19:43):
Or imagine like a diaper explosion, you know, like loss
of containment in space. I don't know about that loss
of containment. You've had that experience, you know what I'm
talking about. We've all had the like Transatlantic flight with
loss of containment of the diaper like ooh, no, I.

Speaker 1 (19:57):
Did right when a plane was taking off. My had
a blowout on my lap and we couldn't get up
for thirty minutes, and oh man, nobody liked me. And
it brought a change of clothes for her, but not
for me, but she sat on my lap anyway. All Right,
these problems can only get more difficult in space. So
we don't know, for example, that women's hips will be
able to survive childbirth, and we just generally don't know

(20:18):
if you can survive a lifetime. But maybe you can.
So let's say that you can. Let's say that not
only can you survive, but you can also go through
reproduction in zero gravity, which again I think is highly unlikely,
but we don't have a lot of good science for that.
There's a lot of reasons why you'd want at least
a little bit of gravity, and you know, a lot
of them have to do with things like using the restroom.
So we talked a little bit about how that's unpleasant.

(20:40):
At the start of the show.

Speaker 2 (20:42):
My gooey imagination is filling in the details for me.

Speaker 1 (20:44):
Yes, oh oh yeah, you're really into Guey today. It's
only going to go downhill from here. When I was
researching a city on Mars, every space vehicle that I
read about had a story about escapees, where the escapees
were like bits of feces that kind of floated out.
It's hard to keep things clean. Everything is more of
a pain in the rear end. If you have just
a little bit of gravity, Surgery gets easier, restrooms get easier,

(21:08):
farming gets easier. We're almost certainly going to need at
least a little bit of gravity just to like hold
our stuff down and make our lives easy.

Speaker 2 (21:16):
And if you hope that your descendants or whoever is
arriving in the distant Solar System is going to be
able to get off the ship and walk around on
this new alien planet, they're going to have to have
some bones and muscles, right, So it makes sense to
maintain that capacity on the trip.

Speaker 1 (21:29):
Absolutely. So not only are we going to have this
massive object, but this massive object needs to have at
least some areas that are spinning to create artificial gravity,
so that you've got some of that force keeping your
body strong or helping the brown trout swim down the
river in the right direction.

Speaker 2 (21:44):
All right, So we've talked about radiation and that might
be a solvable problem with enough shielding, and we talked
about gravity might be a solvable problem if we have
acceleration or something spinning or something like that. So so far,
I'm feeling kind of optimistic about how our kids' kids, kids' kids'
kids might be able to walk off the ship and
stand on a planet around Alpha Centauri. So let's take

(22:05):
a break, and when we come back, Kelly's going to
tell us about how that's all an impossible dream.

Speaker 1 (22:11):
I'm not trying to be negative today.

Speaker 2 (22:14):
The facts that we're going to get into though, all right,
So we're back and we're talking about whether we could

(22:35):
survive an interstellar trip, whether it's a good idea to
build an arc where people can have their babies and
their babies babies babies can one day visit an alien
solar system, or whether these problems are insurmountable. We've talked
about radiation, We've talked about money, we've talked about gravity.
Now Kelly tell us about knowledge. Why do we need
to make sure knowledge doesn't decay along the way we.

Speaker 1 (22:58):
We've already talked about how difficult it is to store
knowledge in computers, or at least how careful you need
to be to protect it from radiation. But another problem
you're going to have is that the farther you get
from Earth, the longer the communication delay. So if people
are living on Mars, for example, there's a minimum three
minute communication delay, just because it takes a long time
for the message to go from Mars to Earth and

(23:20):
then from Earth to Mars when you're ready to respond.

Speaker 2 (23:22):
I think that's really fascinating because you know, the Earth
is not small, but it's small compared to the speed
of light, So you can have what feels like an
instantaneous phone call with somebody in Tokyo, right, and the
lag is imperceptible. But then once you go to the
Moon or to Mars, like now, it really ruins what
it feels like to have a conversation.

Speaker 3 (23:39):
Right.

Speaker 2 (23:39):
You can ask a question, you got to wait like
six minutes to hear the answer. That's like not a conversation,
it's more like writing letters back and forth.

Speaker 1 (23:47):
It is. Yeah, I mean, I think even on the
Moon you can have a close to real time conversation,
maybe a little bit of an awkward delay. But when
you get to Mars, it's a minimum of three minutes,
a maximum of something like twenty to twenty two minutes.
But when you're starting to get to Alpha Centauri, it's
just going to keep extending, extending, extending, until at some
point you're not communicating anymore.

Speaker 2 (24:07):
So for example, if you like need it support, you're like, hey,
my MacBook is crashing. You don't want to wait four
years for the answer to be like, turn it on
and off again.

Speaker 1 (24:15):
That's right, it's not helpful anymore. At that point you've
probably figured.

Speaker 2 (24:18):
It out, hope, so, or you're all dead.

Speaker 1 (24:20):
Yeah, And I mean that also means at some point
you're gonna stop benefiting from any new knowledge that is
created on Earth because it's gonna be hard to get
it to you and probably at some point impossible to
get it to you. But it also means if somebody
has an illness that you don't have anyone on the
ship who's an expert in that you're on your own
the surgical procedure that you're doing. You better hope you
downloaded a good YouTube video for it, because nobody's gonna

(24:42):
walk you through it in real time. You really are
on your own.

Speaker 2 (24:45):
Yeah, you can't look things up unless you bring like
all of human knowledge with you somehow download Wikipedia onto
your ship's computers. I mean that seems that could be
a good idea anyway, doesn't it.

Speaker 1 (24:54):
No, absolutely, yes, for both entertainment purposes and you know,
knowledge purposes. You should bring as much information with you
as you can. That would absolutely be worth the storage space.
In my opinion, what.

Speaker 2 (25:05):
Do you think takes more storage space? Like Wikipedia or
all the Fast and Furious movies?

Speaker 1 (25:10):
Are you taking Wikipedia in every language?

Speaker 2 (25:12):
Ooh question?

Speaker 1 (25:14):
I don't know.

Speaker 2 (25:15):
We better though, yeah, including the Scottish one. That the
Scottish one turns out to be totally made up.

Speaker 1 (25:19):
There's no Scottish wikip Wait what There.

Speaker 2 (25:21):
Is a Scottish Wikipedia, but it's mostly written by a
guy who just invented what he thought Scottish should sound like.
Oh my god, yeah, it's bad.

Speaker 1 (25:28):
I am regularly amazed by the amount of time that
humans are willing to put into messing with each other.
That must have taken a long time.

Speaker 2 (25:37):
Oh he thought he was doing something good. No, he
was like, hey, nobody else has done this, and I
know how to do it right, so my goodness, the
best intentions. Anyway, you should read that story. It's hilarious. Okay,
but anyway, what is the impediment though, to just bringing
all of human knowledge with us and saying like, all right,
we're gonna be cut off from the mothership or we're
not going to get the latest advancements in quantum computing
at the same moment. Maybe they can beam them to

(25:59):
us as they come in who are a little behind.
But why can't we just bring it all with us.

Speaker 1 (26:03):
You can bring a ton of knowledge with you, but
you know, if you set me down next to a
bunch of textbooks on quantum computing, I could do nothing
with that information. Like I mean, maybe after a couple
generations I could. But this ties into the next problem
that we're going to deal with, which is you have
to pick whatich humans you send with you, and what
kind of knowledge they have, and how many of them
you get. But I'm guessing you had another limitation in mind.

(26:26):
Was it how many hard drives you'd have to bring?
Or should I stop trying to guess what you're thinking.

Speaker 2 (26:30):
No, I think that your point is valid that you
can bring a bunch of knowledge, but just having that
knowledge isn't enough. You need people who can digest it
and people who can put it to work. So you're
essentially saying, make sure you bring enough physicists on board.

Speaker 1 (26:41):
You know, you guys are good for a lot of stuff.
I don't know how many practical problems. Also, you have
to worry about like hygiene interstellar trip, but you should
bring a couple cleanly physicists probably, Yeah.

Speaker 2 (26:57):
I think the real problem here is that you need
a breadth of notice, right, And so there's a question of,
like what is the minimum size of a community that
has enough technical knowledge and expertise to basically run independently
of Earth, Because it's not like two people, it's not
ten people. And I'm guessing that's where you're going to
go next, is like how big a community you need
not just have the knowledge, but also to like have

(27:19):
healthy babies.

Speaker 1 (27:20):
Yeah, so I'm going to be focusing on the healthy
babi's part, but this occupation's part is really important, and
it's very hard to have a concrete answer for it
because it depends on what you're willing to live without.
I heard once that there's something like one hundred thousand
medical specialties, and that number seems unreasonably large. But let's
even say there's like a thousand medical specialties. Okay, you'd
probably want one person from each of those specialties, or

(27:43):
like duplicates of all of those people, but you also
need janitors and plumbers and engineers and farmers, and there's
just so many different kinds of people you would like
to have there, but you might not be able to
have everyone you want there. Like, you know, you probably
couldn't have three of every remedical specialist if there are
one hundred thousand kinds, So you're gonna have to sort

(28:03):
of pick and choose and decide what you're willing to
do without.

Speaker 2 (28:06):
I think there's also an interesting interplay there between are
you just trying to survive the trip or are you
trying to bring the seeds of a future civilization with you?
Because think about just like pencils. Okay, you need a
lot of pencils on an eighty thousand year journey. Maybe
you could just stock a bunch of pencils, right, bring
a bunch of pencils, or like light bulbs or whatever,
and you might be able to survive the journey and

(28:27):
not use up all the light bulbs and pencils. But
once you get there, you might still want light bulbs
and pencils in a thousand years. And so what you
need to do is bring like the manufacturing capacity to
produce all of the goodies that we expect for a
certain quality of life, or to severely restrict the goodies
that you're expecting these people to live without. So you

(28:47):
really need to bring like your entire manufacturing supply chain
and pipeline with you if you're going to seed a
civilization on the other end of this, not just like
visit Alpha Centauri and turn around and come back.

Speaker 1 (28:58):
Yeah, so let's jump for a second to a conversation
about what you bring with you. So, yeah, you would
want to maybe bring all the manufacturing stuff to make pencils. Additionally,
we should have invited Katrina on the show briefly, because
you're going to want to make sure, for example, you
have a diversity of microbes, But how do you know
which ones to bring?

Speaker 2 (29:13):
You just bring all the poop on Earth. That's the
easy solution, that's what she would say.

Speaker 1 (29:16):
Okay, but a lot of that poop on Earth has parasites,
And while I don't want to live in a world
without interesting parasites to study, I think most people would,
although I prefer parasites that aren't infecting people. But anyway, so, yeah,
you got to figure out what kind of microbes and
that requires knowledge that we don't necessarily even have yet.
What kind of microbes do you want to bring with you?
But you also need to bring medicine, but medicine expires,

(29:38):
and eighty thousand years is a long time, so you're
probably going to want to bring the equipment that you
need to make more medicine. And there are some designs
for three D printers that will print medicine on demand,
but you need to make sure you've got the raw
materials for that.

Speaker 2 (29:50):
Yeah, exactly. It feels like you're cutting that very tip
off a very complex pyramid of manufacturing and civilization, and
it's going to rumble eventually. It feels very difficult to
maintain the same level of civilization if you're not bringing
the whole pyramid with you. And it turns out the
pyramid is huge, right, Like, just to make a pencil
requires an enormous manufacturing capacity and lots of different specialties.

Speaker 1 (30:14):
Our global supply chains are amazing. We rely on them
for so many things. That pencil takes a million people.
Thing came from somewhere in one of these days. I
want to figure out, was it a Milton Friedman essay?

Speaker 2 (30:24):
I do no holpu with't Malcolm Gladwell, because you can't
trust anything in these.

Speaker 1 (30:30):
We're on the record now, all right, let's go ahead
and just accept that there's a lot of stuff that
you're going to need to bring if you want to
keep your standard of living reasonably high, and also a
lot of stuff that you're going to need to bring
or be able to build so that you can replace
parts of your ship as they break down over time
in the very harsh environment of space. So now let's
jump to biology, the good part. Let's get to the

(30:51):
good part.

Speaker 2 (30:51):
All right, Are we talking about parasites? Minimum number of
parasites to bring to allisantaries?

Speaker 1 (30:56):
Unfortunately, No, I couldn't figure out a way to really
shoehorn parasites and more than once.

Speaker 2 (31:01):
I'm ready for it though, when you ring it up,
I'm ready for it.

Speaker 1 (31:03):
Okay, good, But how.

Speaker 2 (31:05):
Big a group do we need, like biologically to keep
our community healthy and to make sure we don't all
suffer from some genetic defect that like one guy has
on board? How big a population do we need?

Speaker 1 (31:16):
Yeah, this is a really difficult question. So we don't
necessarily know what kind of diversity we need. So it
would be great to have people, for example, that are
resistant to radiation in case we can't shield all of it.
But we don't really know what genes are important for
that at this point. So the more diversity you can have,
the better. You also want people who are not closely

(31:36):
related to each other, because we all have some genes
that are carrying the code for negative traits. So you know,
it could be sickle cell anemia or something like that,
where if you get two versions of the gene that
cause the disease, you're in a lot more trouble than
if you just have one.

Speaker 2 (31:52):
I wonder, from an evolution air point of view, if
this is a scenario where you actually want to be
susceptible to radiation because it induces a higher mutation rate
in your babies. And that might mean that you lose
a bunch because like they have bad mutations, But you
also might like invent some new weird like spacefaring, hearty
human that can like I don't know, extrude pencils from
some new orifice or something you're useful. I don't know, Like,

(32:14):
is there a possibility there that more mutation might actually
be beneficial?

Speaker 1 (32:17):
So mutation is a mechanism through which you get more
genetic diversity, and some of that could be good. I
think our expectation would be statistically, you'd probably get a
lot more things breaking than a lot more things resulting
in pencils coming out of your nose at appropriate times
or something. And I think a lot of those mutations

(32:38):
are going to be you know, like causing cancer as
you're older, and not necessarily resulting in like really well
adapted babies. But who knows, who knows? All right, So
I've seen a bunch of estimates for how many people
you need, and you do need to be careful about
who these people are. So like, yes, we talked about
you want doctors and stuff like that, but when you're
thinking about the number of people you need, the number
of people over sixty, it's great to have their knowledge,

(33:00):
great to have their help, but they're not going to
be contributing to having children. So you need to think
about the number of reproductively aged individuals. And you need
to think a little bit about the mix of people.
So if you bring you know, ten thousand men, you
better also have artificial wounds or something at that point.
So you need to think about the makeup.

Speaker 2 (33:19):
Well, dig into that for a moment for us, Like
what is it best gender ratio? I mean, because like
a woman can't be pregnant from two men simultaneously, but
a man can have multiple partners.

Speaker 1 (33:27):
It depends on what your goal is, and frankly, it
depends on what your culture is willing to accept, because
I think you don't want to send people into interstellar
space under conditions that they would, you know, find abhorrent. Yes,
if your goal is to just have as many babies
as possible, and you've set up the interstellar ship to
be able to scale, to feed and provide oxygen for
a rapidly expanding population, then you could send exclusively women

(33:50):
who got pregnant using embryos that you sent with you.
There are ways to maximize the speed at which the
population increases, but I don't necessarily know that the goal
and root is going to be to increase numbers as
fast as possible, because if you just wanted to have
a lot of people, you could have just started with
a lot more people. So I think you want to
find a makeup where you can sustain your population numbers,

(34:12):
and I don't necessarily know if the best way to
go is fifty to fifty.

Speaker 2 (34:16):
Well, I think your point is a good one, though.
If you want your people to be happy, then you're
going to have to create an environment they're going to
like to live in. And currently most people enjoy monogamous
relationships or you know, one to one ratios, which means
you're going to need roughly a gender balance.

Speaker 1 (34:31):
So I found an estimate where someone did a computer
simulation and they found that you could possibly get away
with ninety eight people.

Speaker 2 (34:38):
If ninety eight thousand or ninety eight people.

Speaker 1 (34:41):
Ninety eight individuals. What if every generation they mate it
with whoever a computer program told them to mate with
based on their genetic makeup. So this is an interesting
thought experiment for a lower bound but if you're thinking
about what humans are willing to accept, that's probably not
going to work out.

Speaker 2 (35:00):
And for this study, how do they define success? You
have like a population downstream that's healthy and doesn't have
a lot of recessive traits that are hurting people.

Speaker 1 (35:10):
I forget the exact details, but it was something like
after five generations, would you expect the population to still
persist or would they have had inbreeding problems or something
like that.

Speaker 2 (35:19):
Well, it's really fascinating because I've heard some of these
studies that speculate the humanity might have had bottlenecks early on,
you know, down to like as many as ten thousand
individuals on the planet, and here we are, you know,
eight billion people later doing pretty well. So it's not
implausible to me that you could get down to a
few thousand. Ninety eight seems kind of crazy.

Speaker 1 (35:39):
And there are plenty of people who will also point
out that there are indigenous peoples living in populations of
something like one hundred to five hundred. But what those
numbers often miss is that those indigenous populations are often
interacting with others and intermarrying, and so actually the population
that is interbreeding is much larger than the individual communities themselves.

(35:59):
But yeah, I've I've seen estimates that seem pretty reasonable
that range from about five thousand to forty thousand people
of reproductive age. The forty thousand numbers seemed a little
bit more realistic to me. So it was taking into
account the ability to survive five generations even if a
black plague like catastrophe comes along. And so this is
incorporating like what if some bacteria in our gut mutate

(36:23):
and kills twenty five percent of us, Like you might
have to assume that every once in a while you're
going to lose people. So estimates range from ninety eight
to about forty thousand, and really depend on the assumptions
you're making well.

Speaker 2 (36:34):
Keeping in mind our constraints. Even if money isn't an optical,
of course, in reality it is. And we know that
size is an issue and fuel and all that stuff,
and so if what we want to do is keep
the ship small, then we want to keep these numbers low.
And that was really interested in your comment about how
you could keep it down to around one hundred if
people accepted, you know, computer assigned dating. And I'm wondering

(36:55):
how far we could push that, Like, could we make
an even lower if we assume some sort of technology
to like modify your genetics or correct issues or something
that couldn't the interaction between biology and technology really change
how small we could go.

Speaker 1 (37:09):
I hear a lot of engineers propose stuff like this,
and it totally makes sense. It's true, it could work,
But when ideas like this come like head to head
with human behavior, they tend to fall apart. I mean,
you could have five women who start the trip with
a vat of freeze dried sperm from lots of different people,
and you could maybe make it. But now you've got
problems with well, do you have enough doctors and enough

(37:30):
engineers and enough people to work the farm. So there's
a lot of reasons why going big has a lot
of benefits.

Speaker 2 (37:37):
I think it's funding the mental image of that of
freeze dried sperm. Why wouldn't you have them, you know,
like delicate test tubes, you know, imagining like you know,
liquid nitrogen flowing over them and something. Instead your words
give me a mental image of like a barrel of
the stuff.

Speaker 1 (37:52):
You started this guy theme, and I was just kind
of running with it. But you're right, they'll probably be
in viles in a tube of liquid nitrogen or something
like that. Yeah, treat them better.

Speaker 2 (38:00):
Delicately, clinking glasses and stuff like that.

Speaker 1 (38:03):
That's right. Having technology to help with reproduction and bringing
along extra genetic diversity in the form of embryos, stuff
like this can really help with diversity problems. But again,
each generation you're going to have to deal with the
wants and desires of the humans who are there, who
are going to want to find partners that make them
feel complete, and who may or may not be comfortable
with being told, hey, your partner isn't as genetically diverse

(38:26):
as you might want. Sorry, this is what five generations
and an interstellarship does. So you are going to have
the embryo for which we provide fifty percent of the
genetic information, and not everybody is likely to love that.
And then what do you do when people get pregnant unintentionally?

Speaker 2 (38:42):
Yeah, exactly. I think that's super fascinating and it touches
on another whole area of questions of like how you
manage the people on board, and what laws do you
have and what punishments can you do? Like you're shooting
people out the airlock if they're not being the right person.
It's crazy, But you know, on ships, the captains in
charge and for a reason. And so anyway, that's whole
other issue we could dig into another time of laws

(39:02):
on board interstellar trips. For now, let's take a break,
and when we come back, let's hear about a strategy
that might make that all moot. What if everybody just
sleeps their way to Alpha Centauri? All right, we're back,

(39:29):
and we are facing all the questions for taking humans
to another solar system. Radiation and gravity and greeding and
knowledge and all these things require keeping people awake, having
a functioning society on board, people sitting there munching on
their snacks and watching fast and furious. What if, Kelly,
we decide not to What if we just put everybody

(39:50):
out for the journey. What if we can freeze them
or hibernate them. You see this a lot in science fiction.
Is that realistic? Where is the technology now?

Speaker 1 (39:58):
It's not realistic with current technology, But I wouldn't say
it's absolutely impossible. You can't just put everybody to sleep
as sleep is technically defined, because while you're sleeping, you
still have metabolic processes happening. You're still aging. So if
you were asleep, you'd still need to have like fluids
put in through an IV. You need to be fed.
Machines would have to roll you over. Sleeping wouldn't really

(40:20):
cut it.

Speaker 2 (40:20):
It'd be like a coma, and nobody wants to be
in a coma for eighty thousand years, and you can't
live that long even in a coma, right. It doesn't
extend your life to sleep.

Speaker 1 (40:27):
Right exactly. That's a total nonstarter. The next step up
from that would be hibernation. And so hibernation you have
a reduced temperature, you still have some metabolic stuff happening,
but the metabolic activity is way down, so like your
caloric needs go way down, you need less you're using
the restroom less stuff like that. And there's lots of
animals that hibernate. You know, You've got bear, squirrels, marmots,

(40:50):
prairie dogs, crowned hogs. Hibernation happens a lot, but it's
worth noting that one hibernation doesn't keep these animals alive forever,
and sometimes animals die well hibernating, so it's not like
you're one hundred percent safe when you go into a
hibernation state.

Speaker 2 (41:05):
And can every animal hibernate? I mean bears and squirrels,
they do these things themselves, but like I've never hibernated.
Do humans hibernate?

Speaker 1 (41:11):
I would like to hibernate sometimes when it's too cold out,
but no, humans do not hibernate. It's not clear how
we would put humans into a hibernation like state. It's
tantalizing that other mammals can do it, but it doesn't
necessarily mean that if we learned the right tricks, humans
could do it too. Humans do sometimes survive being very cold,
so like in a very hypothermic state, and every once

(41:34):
in a while if people have particular problems. So I've
read about somebody who had rabies, and they were trying
to slow down the movement of rabies and give the
body some time to respond in the vaccine, some time
to work. And so they essentially put the person in
a very cold state to slow things down. And people
can survive, but it's not like it's great for the body,
and it's not like it's extending their lifetime. So you

(41:56):
would still end up with people dying in a hibernation state.

Speaker 2 (42:00):
Probably all right, So we can't just knock people out
with nik will. We can't just turn down the temperature
a little bit so people get cold and hibernate. What
if we go even colder? What if we like dip
everyone in liquid helium and turn them into humansicles? Will
that help? Is that possible? I mean, you hear about
this all the time on science fiction and on the

(42:22):
Simpsons for example, or Futurama. I forget which one it is.
But is this just fictional nonsense or is the science
moving us in that direction?

Speaker 1 (42:29):
Scientists are trying to move us in that direction, some
of them are. So there have been people who very
soon after they passed away, had their body cryogenically frozen
in the hopes that at some point will figure out
the cure for their disease, or figure out some way
to sort of wake them back up again, or figure
out some way to upload their brain to a computer
once we really understand brains, so that their consciousness or

(42:52):
something can be brought back to life.

Speaker 2 (42:54):
Right, they freeze them after they die. Don't you need
to freeze them before they die, otherwise you're just thawing
a core.

Speaker 1 (43:00):
I was under the impression that for ethical purposes, you
do it like as soon as they're dead, and then
hope you can find some way to get everything moving
again to undead them. I mean, you know, people's like
heart stops. You could say they're dead, but you can
get them kicking again as long as you do it quickly.

Speaker 2 (43:16):
Interesting.

Speaker 1 (43:17):
I think that's the plant. But you know, if anybody
has like frozen people and want to tell us about it,
we'd love more information.

Speaker 2 (43:23):
But it's call us at FBI dot gov.

Speaker 1 (43:26):
That's right, that's right. Yes, I'm hoping that you had
permission and signed waivers and stuff first.

Speaker 2 (43:31):
All right, but before we try this on humans, I
imagine we're going to test this onlike frogs or kittens
or something. How is that progressing?

Speaker 1 (43:38):
Well, So, there are some animals that freeze naturally. So,
for example, there are some frogs in cold climates that
have something like anti freezing their blood. So the way
anti freezing your car works is it lets things get
a little bit colder without actually freezing. I think that
there's some combination of that happening and the cells also
using some additional mechanisms to make them robust to avoid

(44:00):
burst as water expands.

Speaker 2 (44:01):
Yeah, I think that is what's happening. I think for
frogs what's happening also is that, like they're producing some
substances and a freeze you say, which maybe prevents ice
crystals from forming, and so like basically, if you dope
water with this stuff, then its chemical properties change. And
I think it's so incredible that water has this bizarre
behavior that when it freezes, it gets larger. It's very unusual, right,

(44:21):
most things, when you freeze them, they get smaller. But
the fact that ice is less dense than water means fish,
for example, can survive in the lake right because the
ice is on the top rather than on the bottom.
But also means that if you freeze, you explode, So
it's this funny double edged sword of chemistry.

Speaker 1 (44:37):
Well, I believe there are some fish in Antarctica who
can survive freezing also if they end up in that
like frozen layer of ice. So the point is there's
a variety of animals that can survive freezing, and while
humans at this point cannot survive freezing, maybe there's some
lessons that we can learn from these animals or from
Tartar grades, to try to figure out a way where
we could cryogenically preserve life people thaw them out and

(45:00):
bring them back to life. But it's worth noting that,
as far as I know, there's never been a frog,
for example, that was frozen for ten thousand years and
then brought back to life. You know, like we talked
about some tartar grades that managed to be frozen for
a very long time, but I think you know, when
you get to vertebrate level, it's even harder to survive

(45:20):
freezing for a very long time. So it's not clear
that cryogenics will be compatible with the human body, or
that it will be compatible with the human body on
the time scales needed to get to alpha centauri.

Speaker 2 (45:31):
It's too bad we don't have the biological technology of plants.
You know, seeds are incredible. I read stories where they
like dug up ancient seeds and like planted them and
gave them water and they sprouted, and there's like, oh,
here's a date palm whose parent grew like thousands of
years ago and it just sat there it totally shelf
stable for thousands of years. It's incredible biological technology. It's

(45:52):
too bad we don't have seeds.

Speaker 4 (45:54):
You know.

Speaker 1 (45:54):
Trees make no sense to me. My husband has been
gardening lately and he'll say things to me about like, oh, well,
you can just cut that branch off and put it
in the soil and you'll get a new tree. And
I'm like, that's not how life works. You can't do
that to me. But it works with trees.

Speaker 2 (46:08):
I know. I remember saying to him, like, why can't
I just stick my arm in the ground and grow
a new person?

Speaker 1 (46:12):
That's right, Yeah, trees are wild. And so some of
the most sci fi ish plans I've come across involve
things like having an artificial womb with freeze dried embryos
that you send.

Speaker 2 (46:24):
With you because embryos we can freeze and revive.

Speaker 7 (46:27):
Right.

Speaker 2 (46:27):
That's amazing.

Speaker 1 (46:28):
It is amazing. Yeah, and so I don't know that
you can freeze them for eighty thousand years for the
trip to Alpha Centauri, but you know, if you get
there faster, and you can probably move much faster if
you don't have squishy humans on board to worry about.

Speaker 2 (46:39):
Some of my best friends have two kids, and both
of them came from frozen embryos. One kid is two
years older, but they're actually the same age. It's just
that one of them has been unfrozen for two more years.
And I think about that every time I see these brothers.
I'm like, you guys are actually the same age. Just
one of you was frozen for two years.

Speaker 1 (46:57):
That is amazing. Reproductive technology is incredible, the things that
we're able to do.

Speaker 2 (47:01):
Yeah, so you're going to put this in the maybe
category that we potentially could develop cryogenic technology that could
freeze humans and unfreeze them after thousands of years. It's
not clear how we would do it now, but you're
not going to say it's impossible.

Speaker 1 (47:14):
I'm going to put the cryogenic humans on the fairly
unlikely Oh no, for the time frames necessary to get
to Alpha Center. If you could get one of those
propulsion techniques to get you there in like five years,
and you just had to freeze people so they didn't
get bored during the trip. Then maybe you could get
away with that. But when you think about what else
humans would need when you wake them up, it starts

(47:36):
getting complicated. So you know, if those humans ever want
to have a fresh egg, you also need to figure
out a way to get the chickens going. You know,
you also need to store the food for them. Like
it gets incredibly complicated. But you know, maybe you could
just bring a bunch of genetic material with you and
have a lot of robots that start planting the farm.
You know, a couple months before the humans are going
to be gestated in the artificial womb, but now was

(48:00):
going to raise them. Like, as a parent, it is
amazing to me how much work it takes to get
children to like just shower or brush their teeth. Like,
there's so much nagging that needs to happen.

Speaker 2 (48:12):
You're out in the crowd and you look at all
those people and you're like, wow, all these people were
raised some parents like taught these humans how to survive
and exist in a crowd, and like be functional, Like,
that's so much work.

Speaker 1 (48:23):
Wow, it is. Yeah, culture is incredible. The fact that
we've managed to get ourselves here by like policing each
other's behaviors is fantastic.

Speaker 2 (48:33):
All right. Well, I see you struggling to not be
the negative nelly and do not want to say no,
it's impossible, but it seems like, yeah, pretty implausible.

Speaker 1 (48:41):
I would say within my lifetime, not gonna happen, right,
But science often has breakthroughs that surprise me, and in
a couple of lifetimes maybe it would happen.

Speaker 2 (48:50):
But the embryos and parental robots thing, that's a cultural issue, right.
We think that technologically that might actually be possible. I mean,
you might get weird humans that might kill all each other,
or they might like launch nukes back at us or something.
But in terms of like getting people to the other
planet and growing them there, that could work.

Speaker 1 (49:08):
Right, It's possible that it could work. I mean, I
think there's a lot of things we don't understand very well.
So for example, when babies are born through a mother's body,
they get slathered in bacteria that are important for the
way their bodies work. They get food to the bacteria
in their guts from breast milk. I think we don't
really understand what would happen to humans if they were
raised by robots and only encountered other babies of a

(49:31):
similar age or other people of a similar age. But
somebody should write a sci fi novel about that.

Speaker 2 (49:35):
Or we should just do it and see what happens.

Speaker 1 (49:38):
Yeah, that sounds totally ethical, totally all right.

Speaker 2 (49:43):
So it sounds like there's a lot of challenges to
getting humans from here to Alpha Centauri. Even if you
solved all the physics problems we raised in the last episode,
there are a lot of biological problems, a lot of
cultural problems, a lot of technological problems to solve getting
the humans there safely.

Speaker 1 (49:57):
Yes, and we didn't touch on a lot of the society,
the all the ethical problems. There's a lot more stuff
we could talk about. And also I recommend ed Regis's
book Starbound, which is all about interstellar travel and some
of the challenges that you encounter along the way. That
was an interesting read.

Speaker 2 (50:11):
So if somebody wants to sell you a ticket to
Alpha Centauri, we're going to officially recommend maybe.

Speaker 1 (50:16):
Maybe yeah, I would not buy that ticket, but I'm
sure other people would, and I'm sure it would be
an amazing experience.

Speaker 2 (50:23):
Yeah, and I hope you enjoy Fast and Furious Number
seven hundred and forty two on your trip.

Speaker 1 (50:28):
Enjoy. Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio.
We would love to hear from you, We really would.

Speaker 2 (50:42):
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