All good things must come to an end, including the sun.
Over the next six hundred million years, the increasing luminosity of the sun will first
cook earth and then later in about 4.5 billion years could engulf earth as the sun becomes
a red giant.
But these are very long time frames, well long enough for us to come up with a game
plan of saving earth from the changing sun.
So here are ten hypothetical, but possible ways we might survive the death of the sun.
Number 10.
Convert the Sun to a Red Dwarf
One hypothetical method of managing a star or mining materials from it is the concept
of star lifting.
Stars contain enormous amounts of material, the vast majority of matter in our solar system
is in the sun.
Like the solar system, this consists of all sorts of materials from hydrogen to uranium
but what’s different is that the sun converts hydrogen to helium through nuclear fusion,
making the sun an enormous source of helium production.
But helium is the problem with the sun.
Unlike a red dwarf, our G type star isn’t convective, and can’t ever use its hydrogen
supply completely.
And as it uses what’s in the core the helium waste product accumulates changing the nature
of the sun.
But it’s within the laws of physics to manipulate the sun’s plasma using magnetic fields,
and differentiate and harvest the materials.
This has a dual benefit in that not only do you get raw materials but you can also manage
the lifetime of the sun by removing mass, especially the helium.
Remove enough mass, and you can convert the sun into an artificial red or orange dwarf
that could extend the inner solar system’s habitability and possibly make Venus into
a new earth, keeping earth going by using mirror collectors to increase the amount of
light it receives from the weakened sun.
This could extend the life of Earth by trillions of years.
But there’s a problem.
The sun has a very deep gravity well, so removing material from it would be energy intensive.
But not anywhere near as much as you’d get if you built a full on Dyson sphere, rather
you’d need a dyson swarm which is much more doable than a solid sphere sufficient to capture
enough energy for a meaningful stellar lifting operation that could eventually over time
manage the sun’s output and lifetime, which starts at roughly ten percent of the sun’s
total output.
If you’ve got no other choice but to manage your star, this method would be the one that
not only saves your planet, but provides you with more raw material than any other source
in the solar system.
Number 9.
Sun Shades
Blocking sunlight is straightforward.
We do it with everything from hat brims to houses.
And since the real problem of the sun is its increasing luminosity, earth’s surface will
be molten long before the red giant phase begins, blocking light is one method of keeping
earth around.
But there is a caveat.
It’s not entirely clear whether the sun in its red giant phase will actually engulf
the earth, or just scorch it to unbelievable, but survivable levels.
If earth is to be engulfed, then this method ultimately is just one of mitigating the inevitable
until you no longer can.
But if it doesn’t grow to sufficient size to engulf the earth, you may be able to indefinitely
control the amount of the sun’s output the earth’s surface receives through star shades.
The idea of putting a baffle between earth and the sun is useful on a number of accounts.
With a relatively small one, you could mitigate climate warming for example, and literally
control the global temperatures of the planet.
But you can also mitigate the brightening of the sun, and possibly even the red giant
phase itself, though that’s problematic and a long shot.
It’s an interesting thought experiment nonetheless though, imagine an enormous black sunshade
dominating the sky superimposed over a reddened giant sun.
Number 8.
Migrating Earth
One option to avoid the destruction of earth and keep it in the sun’s expanding habitable
zone is to literally move earth.
This is both possible, and actually straightforward for something so titanic as to move a planet.
The solar system has no shortage of asteroids, and asteroids can be redirected and their
orbits controlled.
By positioning large asteroids to do periodic flyby’s of earth, the gravitational action
between the two bodies will very slightly change earth’s orbit.
Do that enough times, and the planet will migrate in a meaningful way.
Unfortunately the largest asteroids in the solar system really aren’t that big.
One estimate is that you’d need a million asteroid passes to accomplish it, spaced every
several thousand years to keep up with the sun’s expansion and stay in the habitable
zone.
At the same time however, even with existing technology right now we can in principle divert
an asteroid.
And one you get the asteroid in an orbit to encounter earth, you’d need only to maintain
its orbit to keep it on track for the next pass, something that need not take several
thousand years to do.
So this is really the cheapest method in resources to keep earth going, and one that even with
present technology we can envision planning and doing.
But it would be an amazing sight indeed to watch over time the sun expand in our skies.
Number 7.
Colonizing the Solar System
One way of mitigating the death of the sun is to simply move off this world.
As conditions on earth deteriorate as the sun ages, the habitable zone will move outward
offering other options for formerly uninhabitable worlds to become habitable.
First will come Mars, which for a time will be the most habitable planet in the solar
system naturally, though no matter what we do with Mars it will always require some measure
of terraforming.
But even Mars will lose its period of habitability as the zone moves further out.
By the time the sun reaches its red giant phase however, some moons in the outer solar
system that were once very cold, may warm up to liquid water surface conditions, particularly
Titan which may go through an ocean world phase in its far future.
Other options may include Enceladus for a time, or even Europa for a time.
That’s of course if we haven’t already colonized the entirety of the solar system
by then.
If we did at that point maintain colonies at all solar system bodies, the death of the
sun will be more of an evacuation period than a period of growth.
It could be a contraction of the human empire, where bodies are abandoned as their conditions
deteriorate, including our home planet Earth.
Assuming that we never go interstellar, our last days in this universe as a species may
well be on Titan far in the outer solar system.
Number 6.
Colonizing the Galaxy
One nuclear option for escaping the sun is to simply leave this star system entirely.
It’s been envisioned before of a galaxy spanning human empire where we have a presence
among most stars in the galaxy.
But in reality, this may be unrealistic in that most star systems probably aren’t going
to have earth-like planets.
While you could terraform worlds, colonizing the earths of the galaxy is going to take
priority.
But that’s also an issue of distance, we’d very likely be relegated to generational ships
slowly crossing the galaxy and colonizing whatever we could with entire generations
living in space with no planet at all.
Given that colonizing other star systems is so difficult, we may never opt to do it.
Except in one case.
Passing stars.
Our solar system over geologic time has had close encounters with other stars.
This will continue to periodically happen, and at times stars will pass within a light-year
of the solar system.
This makes colonization much easier, and for all we know inhabited planets have passed
very close to earth in the distant past.
We could envision a colonization model where every time we pass close to another star in
the far future, we colonize its system at sub light speeds taking advantage of much
shorter distances than crossing interstellar space.
It may even be that by the time earth is engulfed by the sun, we’re have been long gone living
next to a nice stable red dwarf, not even remembering our origins on earth.
Number 5.
Colonizing the Multiverse
The death of the sun isn’t the only problem we existentially face in the universe.
Another end comes when the universe itself starts to go black.
This is trillions of years in the future, and we may not make it that long, but if we
do we, and indeed all civilizations left in the universe, will be faced with extinction
because of the dying universe.
Or do we?
It is theoretically possible, though only just so, to create a new universe.
Nature clearly made this one, and some theories regarding black holes is that there is an
entire new universe on the other side of one, if one could figure out a way to traverse
it.
But some ways have been conceived, such as the manufacture of negative matter allowing
you to traverse a black hole, if indeed that’s how they work.
But there are a bunch of big ifs after that, such as the laws of physics being different
in that other universe with you have no way of knowing how different.
You might traverse it and immediately dissolve because matter is not supported there, and
so on.
But without negative matter, we don’t know if that stuff exists or can be made, we just
know the laws of physics doesn’t prohibit it, there seems little way to traverse a black
hole and leave this universe.
Other hypothetical methods of creating new universes in the lab suffer a similar problem,
you can theoretically do it, you just can’t ever interact with it.
So far as we currently know, but that’s always subject to change and with an incomplete
picture of the physics involved as we have, it could be that as we learn more about the
universe new ways of leaving it may come on the table.
Number 4.
Slowing the Perception of time
This option doesn’t actually allow you to survive the death of the sun, rather it puts
it so far in the future from your perspective that it almost doesn’t matter.
Within speculative science there has always been the idea of speeding up the perception
of time, which can be thought of as a sort of superintelligence.
But you can also slow it down, at least hypothetically.
This has two advantages in this case, the first is that it makes it seem like your star
lives far longer than it really does, and secondly it allows you to talk to aliens in
real time.
The first is the sun itself.
Even though its life is finite, if your perception of its existence is slowed by a billion times,
it effectively then becomes a very, very long-lived star relative to your perception of time.
But this has an odd side effect, it means that the speed of light appears to be sped
up from your perspective, greatly so, to the point that communication with another civilization
in the Milky Way would be instantaneous just like calling someone up on a telephone.
Number 3.
Technologically Moving Earth
There are many ways to move objects, even planets in nature, but there are also artificial
ways that are in principle possible, as is occasionally envisioned in sci fi.
You could say that we already do this, every time we launch something into space it imparts
a very tiny, but not zero, push to earth, ever so slightly moving it.
This is not a viable way to move a planet however in that to get any distance, you’d
use up all the material in the planet making fuel.
But electric engines are a different animal.
Some spacecraft have used electric ion engines to impart a small, but constant thrust to
a spacecraft very efficiently.
You’d need a huge one anchored to the earth’s surface, but protruding into space firing
the beam in the trail of earth in its orbit.
You still eventually run into the problem of using up all the materials in the planet
until there’s nothing left, but you could in principle migrate most of earth to the
orbit of Mars using this method.
Perhaps a more viable option would be the construction of a light sail right next to
earth.
Here you can use the power of the sun as opposed to materials from earth.
Here you can use a laser, or even a passive sail that uses the sun’s light itself to
pull earth like a sailing ship.
Either of these methods would take over a billion years to get anywhere, and we may
not have that kind of time with the sun, and the sail would be enormous, åbout 20 times
the diameter of the earth, but the laws of physics don’t prohibit it.
And incidentally, therein lies a series of potential technosignatures.
A giant solar sail or an enormously powerful laser beam should be detectable from a distance
if things line up.
They would also be among the longest lasting technosignatures, running continuously for
upwards of a billion years.
So it may be that if we ever detect an alien civilization in the milky way, it might be
due to them moving their home world.
Number 2.
Giving up and Sending out our Genome
What really represents the survival of the species?
Personal survival is a futile task for a fully biological being.
We’re always subject to accidents, and the longer you live, the more the probability
of a fatal accident.
Without a back up as biological beings, we all meet an end.
But as a species, our longevity is determined simply by our existence.
If humans continue to exist in some form, then we’re still around whether we’re
on earth or elsewhere.
But what ultimately defines us and allows for the birth of a human being is our genetics.
We know cloning is possible, and there are even far future hypothetical ways to 3d print
a person out based on a genetic map.
As a result, rather than sending ourselves out into the cosmos to search for a new home,
we could find that new home and send out our genetics to create new groups of humans by
a probe whenever it finds a suitable world to colonize.
Perhaps even clones of people that once existed.
That’s right, it’s plausible that with advanced enough technology you could in some
sense live again in another star system.
It wouldn’t be you, it would be a clone with completely different experiences than
you had, but in some way it would represent another iteration of you.
And with enough of these probes with these capabilities, the human genome could colonize
the galaxy or even the local group of galaxies or further without an actual human being involved
in the process.
We would be almost immortal as a species having merged biology with technology in a completely
different way than we normally envision that, our only limit would be the end of the universe
as a useful place to be.
Number 1.
Ask for Help
The last entry in this list is both a last resort and the one thing on this list we can
do right now, 600 million years before the sun’s luminosity destroys the surface of
the earth as we know it.
It’s simply to send out SOS messages into the cosmos hoping that someone is more advanced
than we are and can handle the situation either by evacuating earth or performing other tasks
on this list for us if we can’t figure out how to do it ourselves.
This we can do right now.
We have the ability and technology to send out very powerful radio signals in the form
of METI, directed signals to try to contact alien civilizations.
We don’t do them often, but we have in the past with messages such as the Arecibo signal.
We have always so far focused on contact signals, to make contact and exchange information about
ourselves and create a kind of scientific and cultural exchange, but there is another
possibility, that we might in our last days plead for help hoping for a more advanced
civilization to come to our aid.
And what if they did?
We’d have full contact with a highly advanced alien civilization.
And with enough time, the sun will calm back down after its red giant phase and become
a cinder white dwarf.
But white dwarfs emit energy for very long periods of time, so perhaps after the fury
of the red sun ends and it calms back down, if Earth survived it, we could recolonize.
Thanks for listening I am futurist and science fiction author John Michael Godier currently
musing about 3d printing copies of ourselves all over the universe.
This works for all genomes on earth.
We could troll aliens by sending out the genome of a chicken, and they get all excited hoping
for an intelligent counterpart to pop out of the 3d printer, and it turns out to just
be a chicken.
On second thought, bad idea, they could uplift the chicken to superintelligence and send
it back to us and then we have a new retribution overlord showing up with a fryer demanding
the DNA of Colonel Sanders for clones for their fried human fast food restaurants.
The universe sure is a harsh mistress indeed 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.