Marshall Eubanks and his team of researchers are working on a concept for sending thousands of probes to Proxima Centauri to explore the nearest exoplanet.
Guest | Marshall Eubanks, Chief Scientists, Space Initiatives Inc. [@AsteroidEnergy]
On Twitter | https://twitter.com/tm_eubanks?
On LinkedIn | https://www.linkedin.com/in/tmeubanks/
On Facebook | https://www.facebook.com/tmeubanks
Host | Matthew S Williams
On ITSPmagazine 👉 https://itspmagazine.com/itspmagazine-podcast-radio-hosts/matthew-s-williams
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Episode Notes
Marshall Eubanks and his team of researchers are working on a concept for sending thousands of probes to Proxima Centauri to explore the nearest exoplanet. Their concept was selected for Phase I development by NASA's Innovative Advanced Concepts program.
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Resources
Swarming Proxima Centauri: Coherent Picospacecraft Swarms Over Interstellar Distances (NASA): https://www.nasa.gov/general/swarming-proxima-centauri/
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For more podcast Stories from Space with Matthew S Williams, visit: https://itspmagazine.com/stories-from-space-podcast
Swarming Proxima Centauri | A Conversation with Marshall Eubanks | Stories From Space Podcast With Matthew S Williams
Matt: The authors acknowledge that this podcast was recorded on the traditional unceded lands
of the Lekwungen peoples. Hello, and welcome back to another episode of Stories from Space.
I'm your host, Matt Williams. And joining me today is Marshall Eubanks. Marshall is the chief
scientist at Space Initiatives Incorporated, is a former member of NASA JPL, and he has a long
history of startups and work in the commercial space sector.
Marshall: I also work for the Naval Observatory. I have been in my career, radio scientists or
radio, very long baseline interferometry is one of my, I worked on that for a long time. I'm still
working on it done earth rotation. I mean, if I could just say a few words, what we set up first
at JPL and then at the U S and O the U S naval observatory was the foundation of the current
navigation system and also the infrastructure needed to, as I call it, navigate the GPS satellites.
So if you use GPS, if you, if you have a cell phone and you know, look up a pizza place or
something you're going to go to, ultimately that's tied back to very long baseline interferometry
observations of quasars.
And I'm proud to say I helped set that up. And when I say tied to, I mean, like, literally today,
almost certainly right now, there are observations going on to sort of calibrate this whole
system and keep this going. This is a continual thing. It's not just somebody did it back in the
past and it's done.nNo, it's like a continual thing. And one of the things I hope to do is to do the
same thing for the moon. Yes. Which is a little different, but you know, they're the 30, 000 foot
level, more or less the same.
Matt: Now, most recently, you were awarded a phase one development grant from NASA as
part of the NASA Innovative Advanced Concepts Program for your Swarming Proxima
Centauri mission concept.
Marshall: Yes. Tell us a little bit about that. Sure. Okay, well, first we are actually in contract
negotiation on that. So until you have a contract, you know, but we expect to get that contract
by next month. So Then I'll feel like we've been properly awarded it But our idea how can we
send a mission and anything like you know Our lifetimes our kids lifetimes to a star stars are
fantastically far away. Proxima Centauri is, you know, four trillion kilometers or something
like that away.
That's a long, long way. And it would take any of our spacecraft so far, millennia to get to
there, get there. So problem is the, it takes energy to get velocity and you also have to, if you
have a rocket, you have to carry along a reaction mass, as I call it, that you shoot out the back
to send you forward.
And so you're, you're using energy to carry reaction mass that you then lose, like with the
Apollo missions, the whole Saturn 5, was humongous 300 foot high rocket turned into a little
thing that landed on the moon, a relatively little thing that landed on the moon. And where did
the rest of that mass go?
Well, it was both fuel and tanks for fuel and, you know, engines for the fuel. And so it's really
all about carrying fuel. And the trouble with going to stars is, well, it takes light four years togo to Proxima Centauri, 4.24 but, and the Rocket Equation tells you that rocketry is convenient
when you have a, when you need a velocity that's comparable to the velocity of your exhaust.
So, kilometers per second. No problem. 10 kilometers a second. No real problem because you
can get, you can, you know, burn things and the exhaust from that is in the kilometers per
second level. So, you know, obviously it depends on whether you have hydrogen or methane
or solid fuels or whatever you're burning, but that's what, that's how rockets work.
Well, we would like to go at 60,000 kilometers a second to get to Proxima in 20 years. Why
20? Because that's a reasonable You know human lifetime thing. We don't want to take 200
years. It's that's a cathedral not a space mission Um, we want to take something like 20 years
20 years means 60 000 kilometers a second, which means by the way Over a thousand times
better than anything we've done so far and We have nuclear thermal rockets and we could
maybe with a big effort make fusion rockets, but none of those things are, you know, the
exhaust is hot enough fast enough to solve this problem.
Now, if we had lots of antimatter lying around, we could, you know, Maybe do this with
antimatter, but we don't, and we don't think antimatter is a realistic thing because you have to
make it and you have to handle it. And it's very, you know, it explodes if you touch it. So it's,
it's a hard thing. So the solution is laser beaming.
You have the, the, the power sources on earth or maybe on the moon or in space, you have a,
you have a laser, you sign it on a laser sale. And people have gone through this, and what seems
like is feasible is 100 gigawatt laser. So substantial fraction of the whole, you know, energy,
electrical production of the earth of the US 100 gigawatt laser, um, that's pushing a few meter,
a few square meter sale.
Um, I think the current sale design is seven meters across. Um, it's varied. Um, that weighs
only a few grams, three or four grams. And that's not, if you think about a pizza, a pizza weight
means. This pen weighs about 10 grams. So we're taking, talking about something like this that
we turn into this big sheet that's 10 meters, that's the size of the whole room I'm in here, or
bigger, and then put instruments on that, put lasers on that, and all like that, and then send it to
Proxima.
That's a tough, that's tough engineering. And but we think that could work. We think we could
do that. So this is like pushing the envelope in sort of all directions, you might say. But we
think we could do this in maybe 10 or 20 years from now. So in 10 or 20 years from now, we
could launch an expedition.
And what would the, what would the cost of that be? Well, space cost tends to be connected to
mass. You know, if you want to make it cheap, you've got to make it light, small. So the
spacecraft themselves should be relatively cheap. Now, we're not able to calculate the cost. It
might be tens of thousands of dollars even or something like that.
It might be really cheap to launch one of these. The cost is going to be in the laser. The cost is
going to be in the whole laser system, which is going to be this big, huge thing that's several
football fields in size, probably that you're gonna have to put like on a mountain or maybe on
the moon or something and have a nuclear power plant or something, powering it.All that's going to be really expensive, but once you build it. You can launch more. So this, this
idea is not new to us. A lot of people have had it. You don't launch one pie plate or pizza to
Alpha Centauri. Launch lots, launch dozens or hundreds, or even maybe a thousand. We think
a thousand. There's a. The Earth rotates around the Sun.
You can only do this at certain times of day, certain times of year. So maybe in one year, you
could have an expedition where you launch a thousand. Now that's probably about the reason
limit there, but the total mass of those things would only be a few kilograms. The total cost of
them would be fairly cheap.
So the question then is, well, how do you get data back? If each one is autonomous, if you're
just sending a thousand separate little mini spacecraft and they don't talk to each other and they
don't share anything, your data return is going to be really limited. They were talking about,
you know, maybe a few hundred kilobits of data back from, from each probe.
That's like a kind of thumbnail type picture. We want to do better. So we assemble these things
into a fleet, a swarm, they talk to each other, and then they use all of their laser power because
each one has a laser to send back to earth, all of their laser power together to send a coherent
signal back to earth and thus raise the bit rate considerably.
Um, and so you, I mean, if you just think, well, if each one could do by itself, a hundred
kilobytes and you had a thousand, well, that's a hundred megabytes. That's a lot better. Our
goal is to send back a data return that's comparable to New Horizons. New Horizons did a good
job describing the Pluto system when it flew by.
It took a year to get the data back. And we would kind of, we would like to get a comparable
amount of data back in a comparable time, i. e. tens of gigabytes of data back in a year from
the Proxima flyby. And we think with that we can do a lot, a lot of good science, take some
cool pictures, get high resolution, and by high resolution I mean kilometer scale or better of the
Proxima story.
Not all of Proxima b, that's the planet in the habitable zone, but. Pieces of it images of it and
also if there's anything like life there have a good chance of detecting it and certainly if there's
anything like a Technological civilization like ours. I think we have an excellent chance of
detecting it
Matt: In fact, I remember reading your paper there about establishing communications and
yes, it's sending thousands of them, having them sort of boosting the signal. And of course
there's the attrition rate, right? Because –
Marshall: not all. Well, yes. I mean, again, this is something that a lot of people had. We don't
know how dangerous it is out there. We don't know how many it will survive. Is it, you know,
50%, 10%? We don't really know. We'll find out of course, but we don't know.
And so all we're this, this idea is not new to us. If you send out a thousand, you have a much
better chance of having some of them get through than if you send out one.Matt: And well, I sincerely hope NASA does follow through and funds this to completion
because between the swarming Proxima Centauri concept, breakthrough star shot, right. It's
like it would be good to have multiple efforts to send probes to nearby stars.
Marshall: Well, we have been working with breakthrough star shot. We had a contract with
them. That, that work is now completed. The contract has been closed because it was a fixed
time. But we have been working with them and that has really, really helped us improve our
work because it's good to get criticism.
It's good to hear other, other people's ideas. The feedback has been very, very, very important
to us. So I don't regard this as really separate from breakthrough star shot in a sort of scientific
sense, it is contractually, it's not the same proposal. It's a new proposal. BTS is breakthrough.
Starshot is not funding this at all, but we're on good terms with them.
And we talked with them literally weekly. Because we have a weekly meeting set up, two
weekly meetings, actually, that we attend. And, you know, so we'll see going forward.
Absolutely.
Matt: Yes, this, this would be very much a collaborative sort of thing where even if you're not
working directly together, it's like you're both piggybacking off of each other's
Marshall: success and exactly if somebody makes it perfect.
And one of the things that we feel very strongly is that this is a tool that will have utility all
over the place in space. With 100 kilometers a second, we could get to Pluto in a year. We
could get to almost anybody you might care to name that we know of in the solar system in a
year or two. So you want to go to Sedna, you want to go to Eris, you want to go to Makemake,
or you want to go to something closer like Triton, or the moons of Uranus, say.
These little pipelines could go to all of those things very quickly. And they won't tell you
everything. You'll still want to have bigger missions going on. But if you want to do an initial
exploration, we could do that. If you want to like do an exploration of every dwarf planet,
which is now dozens, I think we could do that once we get the system developed, same idea.
Once you get it developed, the cost is in the hardware, deploy these things and laser boosting.
Once you get that, we can send these things chiefly, I think, everywhere. Yes. And that, that's
powerful. That'll be a, a national or international resource that I am sure will be used a lot. I
mean, one of the things we're trying to talk to with the planetary defense at NASA is there's no
reason we couldn't send probe like this to every potentially hazardous asteroid.
They're close by, communication should be relatively easy. And you know, it's just like, if
something's potentially hazardous, let's send a probe and see what, you know, what the rotation
rate is, what it looks like, you know, all that kind of stuff. Oh yeah.
Matt: Absolutely. Rapid missions and in fact, interstellar objects, that's another potential
application that you, you've explored extensively, haven't you?Marshall: If I was Czar of this and I had a laser system and I could do a hundred meters, a
hundred kilometers a second, I would for sure send something to one eye. The first interstellar,
and I would send something to two eye to Borisov. I'll comment Borisov because. Why not?
You know, these are both interesting objects and for centuries to come, millennia to come, they
will be closer than Proxima Centauri.
So as we develop the capability to get, I, I feel like it's inevitable as we develop the capability
to get to, you know, interstellar distances, we will send probes to these objects. Um, even if we
find more, even if we find, you know, if LSST or whatever, finds lots more, we'll still send
them to 1i and 2i, because why not, you know, it's And this is actually something that's
frustrated me because, you know, as you may know, I'm sure you do know that certain
Astronomers and certain people have said, well, maybe one eye was an interstellar scout of
some sort, or maybe a bit of interstellar trash from extraterrestrial intelligence.
But if you really think that, if you're not just sort of blowing smoke, why would you want to
go check it out? It would seem like that would be the thing you'd want to do. Now that might
not be worth a multi billion-dollar New Horizons type mission with a heavy probe and so on.
But I think it would be worth a pie plate.
Matt: Now, your particular proposal for doing that, for catching up with interstellar objects,
that was Project Lyra?
Marshall: Yes, that was, so, if you don't mind, I'll tell you a little history here. I follow and
I'm active on something called the Minor Planet Mailing List, MPML. Which is a mailing list
for amateurs and professionals, astronomers who want to talk about asteroids, minor planets,
and back in 2017, there was a, an email saying, there's this weird object and it has a high
eccentricity greater than 1.
Now, eccentricities can be misleading because if you don't have a lot of data on a planet, New
asteroid. If you, if you just been observed like one or two nights, you can easily have a really
cruddy orbit and the eccentricity can be greater than one and eccentricity greater than one
means it's unbound means it's not from this solar system in theory.
And so I thought, well, because this had an eccentricity of like I think it was three or something.
That's pretty high. And I thought, so I'll look into it. And it had a velocity at infinity. That is to
say the velocity would have, if you let it go all the way to infinity of about 30 kilometers a
second at the time.
And I thought tens of kilometers a second. No, that seemed really strange. And so I was like,
Hey, this should be looked at sort of beating the drum on this, you know, people should be
observing this and it was already past perihelion. So it's going out of the solar system. And,
you know, so one of the things we did was we looked at all the spacecraft that are out there,
Pioneer, Voyager, et cetera.
Does it go near any of them? Well, no, unfortunately it doesn't. So it's not like it's going to fly
by close to Mars or something. An MRO could take a picture of it or, you know, no, it's like
it's on its own. path going very much out of the ecliptic. And even at that time, even at that
time, if you, if you had a mission that was on a rocket that was ready to go, that you couldhijack, and you could have done it at the time we first observed one eye, I don't think you could
have gotten to it.
I don't think even New Horizons or any of those fast missions could have gotten to it. Been
close for some of them, but I don't think so. But certainly by the time it's like clear that it's
interstellar. You know, which was a few weeks. No, it's already out of, it's going away. So
you're going to need to get to it.
And so that's, I started doing orbits and I was like, yeah, to do this, even with a SLS, because
at the time there was no Falcon Heavy or Starship, it was SLS. To do this with an SLS, you
could maybe do it, but you're going to, I mean, for one thing, you're not going to do it this year
because the SLS doesn't exist yet.
And you're going to have to do a solar Oberth maneuver, which is where you go really close to
the sun, so you go really fast, and then you burn your rockets there, so you get, that's the best
way to gain energy, is to do an Oberth maneuver. Go close to a massive body, so you're going
fast, and then fire your rockets.
And then that means you've got to get close to the sun and to do that in a reasonable time, that
means you've got to get to Jupiter and do a gravity assist. So you, you've go out to Jupiter, do
a gravity assist, fall into the sun, and then do this Olbert maneuver and then get out to where
you need to go.
Well, right there, that tells you that's multiple years, right? Cause you've got two, two years or
so to get out to Jupiter and then another two or three years to fall into the sun. So that's five
years or something like that. And, and Jupiter is not always in the right place. And, you know,
and like, and then I found out that this Institute for Interstellar Studies group was working on
the same thing.
I mean, celestial mechanics, of course, the same. So our orbits, you know, we're thinking about
the same. So I was like, we should work together. And we agreed to do that in like about a
minute, I think, in our first conversation. Because we really were working on the same, you
know, ideas, and so we've been working together since then, Andreas Hine and Adam Hibbert,
who's a really, really good Celestial Anamnesis, and Robert Kennedy and some other people,
and we've been working since then, and And basically it's still the same idea with variation.
So maybe you don't go out by Jupiter, maybe you, you know, it's like you got to get this
velocity. You got to, it's actually two velocities you got to get. You got to get this high velocity
to get to it, but you also have to get out of the ecliptic plane. And those are kind of two separate
problems. Um, and so it takes a little bit of finagling to solve them both.
And, uh, but you can do it. Um, and you can get to it. And again, so at the time it was like,
well, if we wanted to spend, you know, a heavy mission, if we, and it's a billion dollars or more,
I mean, if you wanted to have an SLS or even a Starship. Yeah, you could do this. You could
get to one eye. It would take you a while.You're talking about 2040, probably, but you could do it. But that's a billion dollars. Is it worth
a billion dollars? That's a I don't know. That's a decent question. Now, I remember talking to
Jim Green, who at the time was a head of the NASA planetary sciences department. This is
either 2017-2018, saying we should do this.
And he asked me a very simple question. Is it in the Decadal Survey? Yeah, And I said, no, I
mean, Jim, so Jim Green said, get into the Decadal Survey and we can talk. And I'm like, geez.
And the other thing is like, you know, missions are booked, manifested. It's not like you can
fly a Falcon Heavy or a SLS or something like that just overnight.
You got to get on the list of approved missions and you got to get in a manifest and that all that
takes years. At the same time, I was doing some ephemeris work on one eye, and I realized we
don't know where it is very well. It wasn't observed very long in the sort of time scale we're
talking about, i.
e. getting there somewhere between 2040 and 2060, say, we're not going to know where it is
to much better than 100,000 kilometers, a lunar distance, you know, a light second, something
like that. Um, And it's out there in the dark. It's a small object. It's very far from the sun. It will
be very dim unless you're close to it.
And so I don't think a single mission could actually get to one eye. It might be able to find it,
but it would do a flyby at a hundred thousand kilometers, like it was, you know, going by the
moon or something. So it would not get a good picture of it. It might get a few pixels, but it
was, and this is a heavy mission.
So you're going to spend a billion dollars and you're going to get like one pixel out of it. That
seems not likely to fly, literally. And so we started thinking, well, how would you find it? Well,
make a whole bunch of little sub probes and then send them in advance and then have them go
by this 100, 000 kilometer wide window where it might be to find out where it is exactly.
But now if you think about it, that's already close to what Breakthrough Starshot was planning
on doing. So this is really where the two things kind of got together. Well, it's like, well, okay,
if we're going to do that, we'll need to talk between the probes and Gee, that sounds like a
swarm, and then you gotta talk back to Earth.
And that's really where all this came from, was considering how could you get to One Eye, and
how could you find it before you got there. All the probes have to do is say, it's here in this
thousand-kilometer box, say. Divide it up into thousand-kilometer boxes, put one probe in each
one, and the one that says, hey, it's in this one.
And then you could send a heavy mission. Or subsequent light sail mission that's really targeted
on it. It's not just flying by at a hundred-thousand-kilometer distance, but it's like flying by at
a hundred kilometer distance or, or less. So you get really good pictures and you can find out
what it really is and so on.
Matt: Well, I'm glad you mentioned the initiative for interstellar studies, because in fact,
looking back a ways, just to the whole genesis of all this laser sails and interstellar missions,my understanding is that this. Sort of began with Project Dragonfly, which was the initiative
for interstellar studies.
That was their design study, their design competition. From there, that's where we got the ideas
that went into Breakthrough Starshot. Yourself and your colleagues with Project Lyra. It was
interesting, it's sort of like the threads went back to this point, and then they kind of diverged,
and Lyra is something that, as you said, that's something you were doing with the Initiative for
Interstellar Studies, or I4IS.
So, would it be fair to say that after that sort of branching out of ideas, they're sort of coming
back together now, where the concepts for going interstellar, rendezvousing with interstellar
objects, and exploring neighboring exoplanets, that there's kind of been a
Marshall: convergence? Thanks. Yes, I mean, I think there has been I mean another another
thing that we've been working on together is nomadic planets Oh, yes, that is to say planets that
are not connected to any star Now if you believe that there's about as many nomadic finances
there are stars or there are more nomadic planets There are star which is what the data we have
indicates then there should be some closer than the nearest stars So somewhere out there in the
outer cloud or maybe in the inner cloud, I don't know, you know, we don't know, but
somewhere between, and if you actually run through the numbers, if you want a.
A Jupiter sized body, you're talking, and this is very roughly, but we don't really know, so
rough is good. Uh, you're talking about maybe one a light year away. So it's closer than Proxima
Centauri, but comparable. You're talking about Earth sized bodies, or, you know, super Earth,
sub Neptunes. You're talking about maybe a tenth of a light year, and if you're Talking about
series type bodies or lunar type bodies, probably even closer than that.
The smaller the body, the quicker the microlensing is, so you have to have better and better
surveys to capture what they call a cadence. How often do they take a data, a photometric data
point. And right now they're at a cadence where they can find an Earth, probably, but not a
moon. But we will find these, I think, and they will be very interesting to go to.
And, particularly, the ones that are, say, super Earth type, because if you're big enough you
could either have subsurface oceans, oceans with ice crust on them, so you're out there in
vacuum, it's cold, you got a lot of ice on the surface, but underneath you have a, an ocean that
survives by radioactive heating, or you could have like a, a super Jupiter with an, I mean a
Jupiter with a super Earth around, around it.
It's in a sort of like, uh, Europa is, where it's heated tidally, so it's, it's warmed up by that, or if
you actually have, I think it's about a Three or five, three to five earth masses, the Stevenson
planet idea, you could actually have a hydrogen atmosphere that keeps the infrared from
heating enough, a radioactive heating.
If you had an earth like planet with this atmosphere, you could actually have water on the
surface. It can actually be temperate. You could actually imagine a planet. It reminds me of the
Ursula K Leguin story, the Tombs of Atlan or something like that, where you have things that
have always been dark and never seen the light.And the heroine is walking around in this always dark environment, so you can literally have
oceans with breakers and stuff where it's always been dark.
Matt: And, and yes, there has been considerable work done on how rogue planets could, in
fact, still be carrying life forms, especially if they've got like Jovian style moons around them
or Saturn like moons around them.
Yeah, because those wounds would still be warm in their interior because they still are orbiting
there. They're giant.
Marshall: It's really interesting how looking for exo life has really kind of exploded lately. I
am old enough that I actually worked on the Viking Mars mission, which is primarily a mission
to find life.
It did a lot of other things, including the part I worked on, but that was its core was finding life.
And when that didn't work, whether or not it didn't work, it's actually debatable. But The
consensus was it didn't work, and that didn't work, that whole first generation of astrobiology
just was decimated.
I mean, all the people I knew lost their job, had to do something else. It was as bad as Apollo,
the closure of Apollo. And for a long time, looking for life was like radioactive at NASA. I
mean, we've never repeated the Viking mission experiments. We've never done them better.
Levin, who did the label release experiment, he always thought we should redo this.
I know how to do a lot better and propose that a number of times. I don't know how many times
and it just got nowhere. It was radioactive at NASA. It's like, we're not going to touch this.
And, but now I think it's not, and it was actually kind of refreshing because I go to Mars
meetings occasionally and at Mars meetings for a long time, it's like, you just could not talk
about Mars life.
It was just like, no, even talking about Mars fossils was kind of like maybe, but probably not.
And then I started going to ocean world meetings, which are like Europa and Celebes and so
on. And there it's sort of like, how are we going to find life on these bodies? What are we going
to do? Um, hey, it was just so refreshing, you know, I had not heard that conversation with
Mars for decades.
So now this was some years ago, five years, seven years ago, something like that for ocean
worlds. Yeah. That's. And I think that's great. I think we need to do that because one thing we
need to do is find out, well, if there is life on an ocean world, is it like us? Does it have DNA?
RNA? Does it, does it have the same genetic code?
Is it different genetic code? The same set of amino acids, different, you know, these
fundamental questions that we just don't know. So, I mean, I feel like if there's life on a nomadic
planet, that's out there half a light year away, we should go and explore it now. It's again, it's
probably not going to be beachfront property and.I mean, a question I would have is, what about technological civilization and something like
that? If your technological civilization starts traveling around the galaxy with, um, generation
ships, say. Big habitats, where people live their whole lives, going from one star system to
another, would you necessarily ignore?
Nomadic planets that happen to be closer that you could, I mean, if there was a nomadic planet
with oceans and so on that you could get to in 50 years, would you ignore that for a star system
that took you 500 years to get to? I have a feeling the answer to that is no. I don't think a
technological civilization would arise on a nomadic planet.
But I think you might have stuff there. And so I think, you know, again, it's an extraordinary
claim that would require extraordinary evidence, but there's no reason you can't consider it.
Well, yeah. In
Matt: fact, I'd say half the charm of rendezvousing with an interstellar object or getting to
study them up close is that we can learn about what's going on in other star systems without
actually having to go there.
Yes. Yeah. Fraction of the time and the cost. And it's a good way to maybe even figure out if
there could be life in that particular system and.
Marshall: And there's another, there's another sort of planetary thing that, that we are very
familiar with at least one planetary system, our own, which developed from a main sequence
star through what you might call normal planetary formation.
There are other ways to form planetary bodies or asteroids or whatever that we won't know
anything about because they're like, for example. Supernova remnants sure do look to me like
they might form bodies because they have all these filaments in them that look like they might
be collapsing. Planetary nebulae, which are the end state of stars when they throw out a lot of
their gas.
That gas has a lot of metals in it, astronomical metals, you know, carbon, oxygen, whatnot.
And again, there are these things called cometary knots. It sure does look to me like things are
collapsing there. If you had what I call post main sequence planets or asteroids, Or alternative
to a main sequence, like say a pulsar planet, the pulsar planets form in situ by having an
accretion disk that forms and then turns into, I don't know, but I have a feeling all of those
things are possible at some level and will be then some of them will be put out nomadically
into the galaxy.
And right now we don't have any direct evidence for any of that kind of stuff. And as you know,
even with exoplanets, it's like we got all these exoplanets hot Jupiters and stuff. So like, who
ordered that? Solar system is not like that, right? Well, actually, I believe that it's fair to say
that none of the exoplanetary systems we found are really a good match to the solar system.
So I hesitate to say we really understand what's going on out there in terms of like planetary
formation, body formation, body lifetime, so on and so forth, very well. We have models, wehave theories, sure, that's fine. But I have no doubt that when we start exploring these things,
we'll be surprised.
Matt: Awesome. If I may ask you to sort of opine here, assuming that missions to Proxima
Centauri or Alpha Centauri, that these happen within our lifetime, as, as hoped, as anticipated,
and we do get a chance to look at the exoplanets next door, in particular, Proxima b, what
would you Hope or anticipate we might find there just within the modest expectation.
Marshall: Well, I'm also very interested in the candidate one that was discovered about four
years ago, possibly discovered. It has not been confirmed yet, but that's around Alpha Centauri
A. Which is the larger of the two Alpha Centauri's, the binary that's Alpha Centauri itself. And
in fact, we're working on a paper where we talk about going to both Proxima B and Candidate
1, assuming it's confirmed.
I mean, obviously if it doesn't exist, then we have to reconsider things. But now Candidate 1
would be a super Neptune, but it might have moons. And it's in the habitable zone of Alpha
Centauri A, and then you have Proxima B, which is in the habitable zone of Proxima Centauri,
which is a nymph dwarf, which is a flare star, which has very bright flares.
To me, it's like comparing those two things. Comparative exobiology would be very powerful
there. Here you have two cases you can look at that are rather different, but they actually kind
of span the galactic space, you might say, of different kinds of planets. Does one have life? Do
both have lives? I mean, they're actually not that far away.
Do they have the same life as Panspermia possible? There's some fundamental questions you
can begin to ask that I don't know how else you would answer, frankly. And so I think that's
very, very exciting. Proxima gets to within, I think it's 8, 000 AU, Alpha Centauri AB. So if
you were a technological civilization on either of those systems, going to the other one would
seem like almost a slam dunk.
It would be much easier than us getting to Alpha Centauri. So if there is a technological
civilization on one, I would expect it to be on both. Now that's interesting because then you
could say, for example, one of the troubles people have is the false positive problem. Right?
You say, I'm going to look for oxygen.
There's a biosignature. I'm going to look for nighttime lights. There's a biosignature. I'm going
to look for this. I'm going to look for that. And you go and you find it, but it's like somebody
says, well, you know, there's this chemical reaction, or there's this thing here that, that could
explain this abiologically.
But if you find two systems and they have the same sort of signatures, and yet they're rather
different systems, there I think you have a really good case of saying, yeah, this is a real strong
indicator of life, because I would expect the chemistry on these two planets to be rather
different. So if you saw similar biological signatures, you would think that's probably biology.
And people argue about this for years. I mean, for decades, I'm sure. I don't. I don't doubt that
at all. None of this will be accepted. Just, I've talked to astrobiologists. None of them think.That just by finding some chemical at some concentration, you're going to be able to say, yeah,
there's life. They don't think that way.
No, no, no, no one's I've talked to. In fact, they're not even that impressed. It's like, I remember
saying, well, what if we could land on Europa and find DNA? You know, so we've got a DNA
meter, DNA, DNAometer, and we land on Europa. We dig down in the ice a little bit and we
find some DNA. Wouldn't you be convinced that there's life there?
I'm saying, well, no. For one thing, how do I know that's not common contamination from
Earth? But for another thing. You know, well, maybe there's other ways to make DNA that had
to be around before life started almost certainly. So they want more, they want like the web of
life. What's the whole, what's the system like, what does it eat and so on.
And I think we'll eventually send people there. Assuming these planets are at all habitable. I
think there'll be people there. I think not in our lifetimes, maybe not even this millennium, but
I think it will happen. So we're just starting that right now. Yeah,
Matt: absolutely. There's one thing that I keep coming back to.
It's, it's the idea of how this stuff is either starting or coming together in recent years. And just
how we're, we really do seem like we're on the cusp of something extraordinary.
Marshall: We can do this if we want to. Right. It's just like one eye. We could go there if we
want to. Now you can argue about whether we want to spend the money or not, but the simple
fact is anybody who says, Oh, you can't go there.
They're wrong. We could go to one eye if we wanted to. I am convinced we can go to Proxima
Centauri or Alpha Centauri if we want to, and not by sending a generation ship. Obviously you
can send generation ships, you know, you can imagine building this huge ship and it takes 10,
000 years to get there. No, we could send something that gets us data back within a person's
lifetime.
If we want to, so it's a question really, well, what do we want to do as a species? Yeah. And I
think, yes, I think in some ways the signs are positive right now that people are interested in
pushing out and I hope it stays that way.
Matt: Oh, me too. Well, Marshall, I want to thank you for coming on and best of luck with
your NIAC grant and the development of the swarming Proxima Centauri concept.
I also hope to hear more about Project Lear in the coming years. And for my listeners. Keep
your ear to the ground for these missions, because they promise to be very exciting, very
groundbreaking, if and when they are realized. In the meantime, thank you for tuning in. I'm
Matt Williams, and this has been Stories from Space.