One of the great questions regarding the future of humanity is what are we going to do with
the Milky Way. The Fermi Paradox shows us that, so far as we can see, it’s wide open
and ripe for the picking … if we can get out there. And while great distances and energy
required hinder ideas of colonization right now, time solves that problem to a degree.
The galaxy ends up being rather small when you have millions of years on your hands to
cross it.
So, how do we do that? No one yet knows for sure, and no doubt new ways will come up as
study of the subject moves forward. But, as far as this point in time, here are ten ways
we might conceptually settle the galaxy.
Number 10. Advance Scouts and Light Sails
In order to settle a star system in the galaxy, it’s probably best to know what’s there
first before you send living beings out there to do it. You might spot an exoplanet that
at first seems clement. You may detect no biosignatures or technosignatures there, meaning
that it seems to have no life. But that doesn’t really mean much, in that you’ll only see
evidence of life or civilizations on exoplanets from a distance in certain very specific situations.
So, you need to scout out these worlds directly in advance.
There are many hypothetical ways to do this, but many of them from the past are unnecessarily
large. You don’t need a ship the size of Battlestar Galactica to go check out a nearby
world. Rather, it may make more sense to send something very small. A tiny spacecraft, perhaps
the size of an apple or a walnut driven by directed laser from your home world using
a light sail. Even the light of the stars themselves might be used in this way.
Small and efficient seems to make sense here, at least for scouting purposes. But one has
to wonder, how small is small? Decades ago we envisioned giant spacecraft as interstellar
probes. Now it’s very small spacecraft as our technology has miniaturized. Does this
continue? Do spacecraft from alien civilizations become microscopic at some point? If small
is the rule, then the solar system could be littered with such probes and we’d never
know it. Needle in a haystack is not a strong enough analogy here.
Number 9. Project Daedalus and Nuclear Bomb Propulsion
One of the more ambitious conceptual ideas on just how to head out on interstellar voyages
was known as Project Orion. This proposal stems from a series of older ideas stretching
to the early decades of the 20th century, though it was only seriously studied in the
late 1950’s. The concept is simple. Make atomic bomb technology work as a method of
propulsion.
The basic concept is straightforward. You build a huge ship, and then drop atomic bombs
behind it that detonate, and push your spacecraft along through the use of a blast plate. This
concept actually saw quite a bit of development, though there were questions about issues that
might develop with that radical of a form of propulsion. Ultimately though, the concept
was never realized due mainly to nuclear test ban treaties, and a general fear of fallout
when the ship was close to earth.
But the idea of nuclear propulsion of a different sort came onto the table in the 1970’s in
the form of Project Daedalus. Here a fusion rocket would have been used rather than bombs
to propel a multistage interstellar spacecraft carrying tens of thousands of tons of cargo
to another star system at about 12 percent the speed of light. While this concept was
also never realized, it does still offer a future possibility for humanity in reaching
out for the stars.
Number 8. Hollow Asteroids and Generational Ships
The concept of getting on a ship knowing that you will never reach your destination within
your lifetime is perhaps a little disconcerting at first. You would not just be condemning
yourself to spending the rest of your life on that ship, but also your offspring, and
their offspring, generation after generation until, after centuries, your descendents reach
their destination.
This is the concept of a generational ship, and remains one of the more viable ways we
might colonize the galaxy. And, in the great scheme of things, it would not take that long
to establish outposts all over the Milky Way. The reason for this is that the Milky Way
is only about 100,000 light-years across. At sublight speeds, establishing a presence
throughout it could probably be done in ten million years or so, at least in principle.
In a universe that has trillions of years to live, that’s not that much time.
The original ideas for generational ships come from rather surprising sources. Early
writers on the subject include the father of astronautics Konstanin Tsiolkovsky, and
rocketry pioneer Robert Goddard. NASA’s Goddard Spaceflight center? Yes, that guy.
The idea requires that the ship be entirely self-sufficient in every way. Food for generations
after generations of occupants would need be grown. Everything would need to be recycled
with 100% efficiency.
And there is the human side to this. Imagine someone being born on the ship that doesn’t
want to be there. Yet, they can’t ever leave it, opening up ethical issues … but it must
also be said that Earth works like that too, at least right now. It’s sort of hard to
quit earth, though that may change in the coming years.
Other issues include questions of what might culturally happen over generations, would
they cut ties with earth? Would they develop politics that earth doesn’t like? Would
they form factions? Would they wage wars with each other on the ship? Could their society
break down to such an extent as to destroy the ship?
Engineering such a ship has been envisioned to be everything from a hollowed out asteroid
to a heavily shielded ship. It would be a daunting task, but again, is in principle
possible. But there is one aspect of the generational ship idea that’s rather interesting. Technology
improves, so if a generational ship left to colonize a world 1000 light-years away, and
they cruised at a speed of say one tenth the speed of light. They may actually get beaten
to their destination by future humans that have ships that can go faster. By the time
these pioneers reached their destination, they may find a fully developed human colony
already there. What happens if they aren’t interested in letting anyone else in?
Number 7. The Empire of Humanity and the Alcubierre Warp Drive
The question of faster than light travel has been a constant theme in science fiction for
many years. One that really was always more a plot device than a concept at home with
physics as we unraveled it across the 19th and early 20th century. Instead, the universe
seems to have a universal speed limit that prevents travel, or any information exchange,
faster than the speed of light. And, that’s not just a term that applies to light. C can
also be said to be a kind of speed of causality, or speed of time, or maximum speed of information
transfer in the galaxy.
But what if there were a way to move faster than light that did not violate the speed
of light rule, but also doesn’t openly violate the laws of physics. One option here is the
Alcubierre warp drive, first formulated by physicist Miquel Alcubierre after watching
an episode of star trek the next generation. Here, we have a ship that forms a warp field
that seperates a piece of spacetime off from the rest of space time. The ship within the
bubble of seperated spacetime would not actually be moving inside space, it would be stationary,
but the bubble of space time itself would be moving and carrying the ship along with
it. This would not be breaking the limit if the ship is not moving, given that spacetime
itself is not subject to the limit.
Ultimately though, as with wormholes or any speculative methods of faster than light travel,
it is fraught with problems such as massive amounts of energy needed to get it going,
a means of slowing it back down, and massive amounts of radiation. And even after those,
you’d still need a form of exotic matter to do it that has never been seen in nature,
or do we have idea how to create it.
But, say we did crack that technology in the far future. Then, we would have a tool that
not only would allow us to build a galactic empire in the Milky Way in short order, but
a multi-galactic empire spanning a large swath of the universe.
Number 6. Slow and Steady
All too often we think of our civilization in terms of being big. We have numerous enormous
cities built on this planet and as our technology advances we keep growing. In fact, the population
of earth right now is more than 7.5 billion and growing and some worry just how much longer
than can be sustained. But that’s a question of a single planet. Not a universe.
Or for that matter a galaxy. The Milky Way contains over 100 billion stars. At our current
numbers, if every single human owned a star system to themselves, well over 90 percent
of the galaxy would still be unoccupied. Even when one tosses out violent short-lived stars,
the amount of red dwarfs in the galaxy is still something on the order of 90 percent
of the stars in the galaxy. Point is, we cannot colonize this galaxy in a meaningful way without
a massive, continuous explosion of human population. One person cannot colonize a planet. It takes
far more than that.
So maybe galactic settlement doesn’t happen very fast because we’re slow at population
growth. Granted that we might do it with machines such as self-replicating probes, but those
might take a bit to self-construct, physicist Gerard O’Neill once speculated that it might
take a century or more for such a thing to mine a star system and self-replicate.
Point is, whether you’re biologically reproducing or technologically self-replicating, this
may take some serious time, and on a galactic scale you may be limited in your expansion
just by the numbers and the humdrum realities of reproducing. And you need the drive to
do that, which is not guaranteed. Politics, distances and realities may make further expansion
undesirable, and stagnation may occur. You may colonize your galaxy in the end, but it
may take far longer than you originally intended. And, that actually already has been the rule,
though with exceptions, with human space exploration so far.
Number 5. Robbing Black Holes and The Halo Drive
One of the funnest aspects of contemplating how humans might colonize the galaxy is that
how we actually end up doing it might not have been thought of yet. As a result, sometimes
a completely new conceptual way we might travel the stars comes on the scene. This happened
recently with a concept called the Halo Drive.
Conceived by Dr. David Kipping of Columbia University, and fellow youtuber over at the
cool worlds channel where he has a very nice overview video on the subject, link in the
description below, along with an Event Horizon interview I did with him also linked, the
Halo Drive offers a way to gain acceleration through the use of a laser and the gravity
well of a black hole, where the laser gains energy as it loops around the black hole and
returns the energy gain to the spacecraft.
This opens the way for entire travel networks, highways, between suitable black hole systems
that might provide an efficient way for humanity in the future to at least begin laying the
infrastructure of a galaxy spanning civilization.
Number 4. Accomplish Full Colonization without Ever Leaving Home
While it’s true that there is a possibility that we may never fully understand the universe,
there is also a possibility that we might. So what happens if we go through the centuries,
or millenia, figure the whole thing out, conclude that we’re probably alone, and there really
doesn’t seem to be much point to colonizing the real universe, at least as we know it
to be real, and rather we could construct one of our own and explore that instead?
Or some variant thereof. Some humans have made a point of heading out and exploring
this world, in fact we’ve done it across our entire existence and spread ourselves
across the entire planet even to inhospitable places like Antarctica. While some will explore
and head out into the universe, some will not, and will instead explore ideas internal
to us. We do this now with novels, games, and all sorts of escapism. Some of it is total
fantasy, but so what, it entertains us and we enjoy the diversion.
But how does this progress? What will be the next incarnation of this escapism? For some
it might be the ability to live in direct virtual reality in a universe such as that
of J. R. R. Tolkein. Others may wish to explore a universe that is easier to understand, should
complete understanding of this one prove to be impossible, and perhaps that might even
lead to clues about how the real one actually works. Will we lose track of this reality,
and forget the real universe entirely? Have we done that already?
At the end of the day, does it really matter if your existence as you know it is in a reality
that itself may not be real, or if it’s in a virtual reality. Either way, it’s existence
of some variety. So could it be that alien civilizations that develop very advanced virtual
realities simply lose interest in the actual universe in so far as they can and just tune
out? Will we do that? Do many of us do that already?
Number 3. Wormholes and Unknown Physics
It has to be said that at this point in time, we don’t know everything. Vast areas of
physics remain undescribed, and it’s always possible that as new descriptions of the universe
are advanced, or already existent ones are refined, then new avenues to space travel
faster than light might crop up.
One example here are wormholes. They are an old idea, going back to Einstein, and might
allow for rapid travel between two points in the universe through a wormhole. The problem
is that we don’t really know how to create one, of if they can exist in nature. The general
consensus is that they would simply collapse and not allow travel through them, and also
would require, once again, some form of negative mass exotic matter.
And there are other problems, such as if the wormhole would take one to not only another
point in space, but in time, creating causality problems. But if such a thing could ever be
created and harnessed, it would be a game changer as far as galactic colonization for
sure, one that’s been well fleshed out in science fiction. But, on this sort of thing,
or indeed completely unknown future physics, it’s best not to hold one’s breath.
Number 2. Temporary Death
For decades now, companies here on earth have offered a rather long-shot service. Reversing
death. It’s called cryonics and it is the ability to freeze a human corpse in hopes
of reanimating it at some later date after the disease that was the cause of death is
cured. While mainstream science is rightfully skeptical as to whether this approach could
ever work, the basic idea in principle seems sound. But, the human body is also very complicated
and delicate, and this may be something that is forever outside our reach, even in the
far future. But, say for a moment it’s not, such a technology could have profound effects
on humanity’s ability to colonize the galaxy.
A state of temporary death would allow space travel over long periods of time and distances
to be accomplished. When the travelers leave their home world, say Earth, they would do
so in a state of death. Essentially a complicated form of freezing known as vitrification. Then,
upon reaching their destination, they could be revived to set up their colony or join
a pre-existing one.
This approach of course comes with many existential questions. What does it mean to wake up from
one’s own grave. Is it a starship at all, but rather a mausoleum, or some combination
of both should the mission not be a success. I can’t imagine it would feel very nice
waking up from centuries of frozen death, nor do I think it would ever be a particularly
pleasant notion going into such a state before leaving earth. In any case, if this is indeed
possible, it very likely lies in the far future and may well be superseded by other technologies
to extend life in the meantime.
Number 1. Self-Replicating Probes and 3d Printing Humanity
Who ever said that a species has to leave home to physically colonize a galaxy? If we
were to attempt it right now, we would have trouble, a theme that’s been present across
this video. But we’re at a stage of technological development where we can envision more.
It has been pointed out, most famously in the form of the Fermi Paradox, that colonizing
the galaxy actually doesn’t take all that much time in the great scheme of things. Fermi
asked, that given that is the case, then where is everyone? And the whole thing gets easier
through the ideas of mathematician John von Neumann. He envisioned self-replicating machines
that can construct copies of themselves using the raw materials of the galaxy, making the
process of putting a probe in conceivably every star system in the galaxy pretty rapid
and straightforward.
So let’s take that further. What of a Von Neumann 3d printer that not only can print
out copies of itself, but other things. Say it can print out biological beings. If so,
we could send out probes that can print out copies of humans to colonize the galaxy. These
printed humans could have the memories of humans that once existed back on earth, or
have a custom set of memories and knowledge specifically for the act of settling an exoplanet,
or both. Or even custom genetics that allow them to live on an exoplanet that an unaltered
human could not.
Or, if the probes can’t do it biologically at all, then they might print out technological
analogues of humans. Sentient robots to colonize worlds where oxygen or phosphorus just isn’t
in the cards. But, one has to ask, in the end, wouldn’t that just be cheating and
the only fun way to colonize the galaxy is do head out there and do it ourselves.
Thanks for listening! I am futurist and science fiction author John Michael Godier currently
personally disinterested in colonizing the galaxy. I am needed here for many reasons
beyond thinning the pastry herd. For Corn’s sake, the war with the garden weeds cannot
simply be abandoned. Nor the dust wars, or keeping the dishes in check! What of the ongoing
laundry campaign, though I guess we’d probably bring that one with us and possibly the dishes
and be sure to check out my books at your favorite online book retailer and subscribe
to my channels for regular, in-depth explorations into the interesting, weird and unknown aspects
of this amazing universe in which we live.