Nature currently has no shortage of stars, we live in a time and indeed a galaxy where star formation
is ongoing and should we wish to to become a kardashev type III galaxy spanning empire,
we will need to colonize a great many of those stars. This is an easy task for the milky way,
the bulk of it is made up of suitable red dwarfs that live for trillions of years.
But there are areas of the galaxy that are not as nice,
such as near a star preparing to go supernova or the high radiation environment of a star cluster
or the galactic center. As a result, some civilizations may conceivably have a need
to artificially engineer stars and galaxies rather than go with what nature provided them.
An example of this would be an inhabited rogue star system that was ejected from
its parent galaxy. There are a huge number of these, intergalactic space is not empty,
but rather populated with huge numbers of ejected stars.
This would limit what a civilization could do, not having proximity to materials
and other star systems to populate as one has inside of a galaxy. Such a civilization
could be seen as locked in, with nowhere else to reasonably travel to outside their star system.
Such a civilization probably would not have the available resources to do this, but they
might wish they could, and that is to build a new star from scratch. This would also be relevant to
any civilization existing in the very far future when the stars of the universe start to blink out,
and all that’s left are cooling remnants, black holes, blue dwarfs, and eventually even iron
stars. The end stages of the universe as we know it greatly limits the options for a civilization
to keep going. But at the same time, there will always be free hydrogen in the universe,
and constructing a new, customized star may be viable in certain circumstances.
The process is actually quite simple, and in a natural form it happens all the time.
To build an artificial sun, you would simply mimic nature. You collect up enormous amounts of gas and
dust and with enough of it, it will collapse into a functioning star under its own gravity.
The simplest way to do this is to collect up hydrogen, the most common element in the universe,
but here it would probably be really difficult in situations such as our own,
we’re nowhere near a nebula, and have no ready access to enough hydrogen to form a star,
other than what already exists in the sun. If you combined all of the
gas giants of the solar system, you’re still far short of what you need to ignite a star.
But if you had a nearby nebula, you could collect up enough hydrogen to start the process. Let’s
take the case of a star made of pure hydrogen, adding in other elements complicates things.
This might initially be interesting, because as you build up the mass,
you are first essentially creating an artificial gas giant made up entirely of hydrogen.
As you keep going, your artificial planet gets increasingly dense
as everything becomes compacted due to the increasing gravity. Eventually you add so
much that you get into brown dwarf territory and that’s actually where fusion can begin.
While a brown dwarf can’t fuse normal hydrogen and if your star is entirely normal atomic hydrogen
you won’t get anything, but in nature brown dwarfs can actually fuse deuterium and large
ones can fuse lithium. So the road to stellar fusion actually starts with the brown dwarfs.
In the artificial hydrogen star however, what does happen is increasing heat,
so much so that the brown dwarf will begin to look like a very dim glowing star. Eventually,
nuclear fusion of normal hydrogen begins in the core and then you have a star proper,
starting about 0.08 solar masses. This would be a very unnatural red dwarf,
and indeed would be a technosignature because anyone taking a spectra of your creation
will see a lack of any other elements, most notably helium, in the make up of the star.
From here, you can add more mass if you wish, moving through orange dwarfs and Type G stars
like the sun. You probably don’t want to exceed that however, as stars more massive than the sun
get increasingly short lived, and eventually you get into exploding supernova stars. But
once a civilization gets to the stage where it can actually construct stars,
or manipulate natural ones, some interesting ideas come into play. And this leads to
another potential technosignature, a very unambiguous one. Arranged stars.
Through the use of hypothetical devices such as Shkadov thrusters, you can use a star’s energy
to propel it and move it around. This allows over time for the movement of stars and the arrangement
of them in some advantageous way, such as a system of interconnected colonies at set distances from
each other, which could aid in communications networks and ease of travel between the colonies.
This could allow for a species to alter a galaxy, and essentially make an artificial galaxy,
or create an arranged artificial satellite galaxy to a large resource rich natural spiral galaxy,
potentially even being made up entirely of constructed arranged stars. Such a galaxy would
look inherently unnatural and would rank high on the list of the largest possible technosignatures,
though no one in our local group of galaxies appears to have done this.
But there’s also another way to alter a galaxy, and this also would be conspicuous and visible at
great distance. Known as red spirals, these hypothetical altered galaxies would show an
unusually reddened light profile due to the alien civilization that’s colonized that galaxy
kicking out potentially dangerous stars, or star lifting them on a massive scale
in order to no longer be a dangerous class of star. In other words, supernova mitigation to
maximize what you can colonize in a galaxy may be a concern for a type III supercivilization.
On a much smaller scale, another option would be to construct an artificial planet.
This option tends to be taken in futurism from the perspective of a giant megastructure that
serves some of the functions of a natural planet, including ideas like ringworlds and dyson spheres.
But that’s creating living space, not so much a planet.
In the case of creating an entire planet artificially in the same grain as earth,
you would need a lot of material, but in this case nature provides this material in abundance
in certain cases. An example would be a very young star system with a protoplanetary disk.
You might choose this option if your home star system is passing nearby such a young star system,
and rather than simply hope that a system has suitable habitable exoplanets, you can custom
create one. In this case you can create them by managing the protoplanetary disk’s planet
formation. Simply add or subtract material at the right orbital resonances and you could create
a series of planets with perfect habitability in the same star system, all tailor made for your
purposes. On the other hand, planet formation is a rough process, and new earth-like planets are hot
and volcanic for a very long time, so no matter what you do with an artificial planet analogue,
you’re going to have to wait a very long time for it to be habitable in the sense of earth,
and you’re going to have a very long period where that planet will be something
similar to a younger earth, with entire mass extinction events due to rampant volcanism.
But there are ways to hypothetically mitigate damage caused by natural disasters,
or construct your planet in such a way as to minimize their occurrence.
Once you achieve that however, through terraforming you could create an earth,
and again, the result would be a nominally visible technosignature in a light curve due
to the weirdness of artificially placed planets transiting. One possible wildcard here is the
use of molecular nanotechnology to automatically assemble planets in protoplanetary disks for you.
It’s unclear what the end result of highly advanced nanotechnology is,
and building a planet quickly using this method is physically impossible,
it is hypothetically possible to use it over long periods of time
to perhaps build habitable planets faster than nature otherwise could have done.
The main limit again here is heat, but that’s an issue with any molecular nanotechnology,
it can’t work so fast that it melts itself, thus there is a speed limit on what it can do.
In reality, though, solid planet construction is probably not something that’s as practical
as building structures that mimic the functions of a planet. It’s far easier just to construct
a huge number of habitats, such as O’Neill Cylinders, that generate artificial gravity
through their spin, filled with perfectly climate controlled facilities in which to grow crops,
and as close to a 100% recycling rate as you can get for raw materials, water,
atmosphere and so on. But that’s also from the perspective of humans. We can theoretically do
without a planet in space, but this may not be the case for some alien civilizations.
One can envision alien species that may not so easily live in space, you can grow corn on an
o’neill cylinder, but it would be very difficult to grow a 10 square kilometer fungus, possible,
but better done on a planet. Earth’s existing giant funguses probably won’t be going to space,
and I’d imagine the whales probably won’t be either, despite Star Trek IV, which as good of
a movie as it is, what pleases me more is William Shatner making two whales not only go to space,
but also fly past the sun and time travel to the future.
Other possibilities for artificially constructing objects in nature include black holes,
of which there are varieties that might be of great use. If you get enough mass together,
which once again is an enormous amount of material, you can create
a custom black hole in principle through similar means to constructing an artificial star.
But there is one last possibility, and this one may not require a Kardeshev type three
civilization, and in fact may only be a few decades in reach from us right now.
And it’s both the biggest project imaginable, and its implications are outright spooky.
It’s an artificial universe, and it’s possible that we might live in one,
and as such would be the biggest technosignature of them all.
This involves the genesis of the universe itself. Within quantum physics, virtual
particles can pop in and out of existence on quantum scales. This led to the question
of whether a universe could do this, where a tiny bubble of space pops into existence from nothing,
and then somehow inflates into the universe we see around us. This is unsettling in a way because it
means that the answer to the question of what happened before the big bang or what set it off
simply is nothing. It all came out of absolute nothingness as a result of the laws of physics.
Something as complex as the universe occurring from nothing however invites the opposite
question, what if it wasn’t from nothing. What if we could create an artificial universe?
What if someone else has? One potential answer to this question is figuring just how universes
come to be. One option involves a particle known as a monopole, which is predicted to
exist in nature but none have ever been found. In a giant particle accelerator, bigger than anything
we currently have, a monopole might be used as a seed. If you apply massive amounts of energy, it
might inflate and become a universe, but it would not do so within our universe. Rather it would
create a wormhole, and on the other side of that wormhole would be a brand new expanding universe.
If that experiment ever pans out, it means that universes can be artificially created.
Assuming that such a universe has the same parameters as its parent, which may not
be the case, one can imagine being inside of such a universe. It would not be a simulation,
rather an outcome of nature and physics. But that it happened artificially brings
in the question of how likely it is to happen naturally versus technologically.
The answer may be that technologically it may be more likely, and then we’d have to ask if
we ourselves live in an artificial universe. Who were the scientists that created it? Why?
Was it just an experiment? And if we ever create an artificial universe of our own, how would the
denizens of such a universe feel if they ever found out it was us that created their universe?
Thanks for listening! I am futurist and science fiction author John Michael Godier currently sorry
for mentioning them again, but the turtles holding up the earth thing is starting to
sound better than either something from nothing or something from something, either way. Wait, unless
it was the turtles that created the artificial universes. Every big bang starts with a turtle,
and then it walks around with a universe on its back. Must be some overworked turtles
and be sure to check out my books at your favorite online book retailer
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weird and unknown aspects of this amazing universe in which we live.