Hello Space Fans and welcome to another edition of Space Fan News.
In this episode, an astronomer from the University of Rochester has recently published a paper
that studies whether a civilization on the level of ours could survive self-imposed changes
to the planet’s climate due to rapidly expanding technological progress.
You’ve heard me talk a lot about great filters on this channel so you’ll want to stick
around for this story.
OK, you’ve heard me talk about Great Filters all the time, these are things that for a
variety of reasons, prevent a civilization from getting past certain points in their
development which ultimately prevents them from exploring and colonizing the galaxy.
Great Filters would be the reasons why we don’t see any other civilizations in our
galaxy and could prevent us from actually getting to the stars.
The more I study this, the more pessimistic I become about finding intelligent life in
our galaxy or in the larger universe.
Starting life from nothing is probably very hard, evolving an intelligence is no cake
walk either, not to mention developing a technological civilization and surviving all the mistakes
that are lurking when you develop advanced stuff.
There’s a lot that can go wrong, and these are cumulatively called Great Filters.
They are things that get in the way and prevent an advanced civilization from reaching its
full potential such as colonizing the galaxy.
Well, among all the possibilities and forms that Great Filters can have, one of them is
making the mistake of not realizing that civilizations and planets don’t evolve separately from
one another; they evolve interdependently, and it doesn’t take a genius to understand
that the fate of our own civilization depends on how we use Earth’s resources.
And if that’s true for us, it most certainly is true for any other civilization that might
be reaching a high state of technological development.
I mean, do we really know if sustainability is even possible?
Can a highly technical society develop without wiping out the host planets resources?
Astronomers have inventoried a sizable share of the universe’s stars, galaxies, comets,
and black holes.
But are planets with sustainable civilizations also something the universe contains?
Or does every civilization that may have arisen in the cosmos last only a few centuries before
it falls to the climate change it triggers?
To me these are incredibly important questions and luckily a group from the University of
Rochester in New York are trying to answer them.
Led by Astrophysicist Adam Frank and published in the journal Astrobiology, they’ve written
a computer model that tries to address these questions from an astrobiological perspective.
By the way, the term astrobiology didn’t even exist half a century ago, this is one
of the amazing new sciences that has developed as a consequence of the Golden Age of Astronomy.
Gotta love it!
Astrobiology is the study of life and its possibilities in a planetary context and that
includes ‘exo-civilizations’ or what we usually call aliens.
Dr. Frank and his colleagues point out that discussions about climate change rarely take
place in this broader context—one that considers the probability that this is not the first
time in cosmic history that a planet and its biosphere have evolved into something like
what we’ve created on Earth.
“If we’re not the universe’s first civilization,” Frank says, “that means there are likely
to be rules for how the fate of a young civilization like our own progresses.”
As a civilization’s population grows, it uses more and more of its planet’s resources.
By consuming the planet’s resources, the civilization changes the planet’s conditions,
and this leads to the mistake I was talking about earlier, this Great Filter may be lurking
in our future if we don’t fully come to grips with this idea.
The results of Frank Et al.’s, model lead to four possible outcomes, the y-axis has
black and red lines.
The black line in these graphs is the population, the red line is the average planetary temperature.
The x-axis is Time.
The first possible scenario to come out of the model is called Die Off.
This is when the population and the planet’s state (indicated by something like its average
temperature) rise very quickly.
Eventually, the population peaks and then declines rapidly as the rising planetary temperature
makes conditions harder to survive.
A steady population level is achieved, but it’s only a fraction of the peak population.
Imagine if 7 out of 10 people you knew died quickly.
It’s not at all clear a complex technological civilization could survive that kind of change.
The second possible scenario is called Sustainability and is the best possible outcome for us and
other technological civilizations.
The population and the temperature rise but eventually both come to steady values without
any catastrophic effects.
This scenario occurs in the models when the population recognizes it is having a negative
effect on the planet and switches from using high-impact resources, such as oil, to low-impact
resources, such as solar energy.
The third scenario is Collapse without resource change: The population and temperature both
rise rapidly until the population reaches a peak and drops precipitously.
In these models civilization collapses, though it is not clear if the species itself completely
dies outs.
And finally the most scary of all: Collapse with resource change: The population and the
temperature rise, but the population recognizes it is causing a problem and switches from
high-impact resources to low-impact resources.
Things appear to level off for a while, but the response turns out to have come too late,
and the population collapses anyway.
The researchers created their models based in part on case studies of extinct civilizations,
such as the inhabitants of Easter Island.
People began colonizing the island between 400 and 700 AD and grew to a peak population
of 10,000 sometime between 1200 and 1500 AD.
By the 18th century, however, the inhabitants had depleted their resources and the population
dropped drastically to about 2,000 people.
The Easter Island population die-off relates to a concept called carrying capacity, or
the maximum number of species an environment can support.
The earth’s response to civilization building is what climate change is really all about,
Frank says.
“If you go through really strong climate change, then your carrying capacity may drop,
because, for example, large-scale agriculture might be strongly disrupted.
Imagine if climate change caused rain to stop falling in the Midwest.
We wouldn’t be able to grow food, and our population would diminish.”
I think this is such important work, that Carol Christian and I have invited Dr. Frank
to attend our Astro Coffee Hangout this Thursday at 3pm ET.
If you want to learn more about this model and the idea of Great Filters, then this is
one hangout you don’t want to miss.
We’ll be live at 3pm ET, but if you can’t make it then, you can always catch it after
the event is over.
I believe Great Filters are out there and they have an adverse effect on intelligent
life in our galaxy.
As we learn more about exoplanets and their conditions, we’ll gain more understanding
about the ubiquity of life, and the commonality of alien civilizations, but from my perspective,
it doesn’t look good.
I’m not so sure there’s that many, if any, advanced civilizations in our galaxy,
we may be first, and only one in the Milky Way.
Well that’s if for this one Space Fans, everything we do here at Deep Astronomy is
made possible by the lovely Patreon Patrons who care enough about this content to support
it and bring it to you.
Thank you all so much.
Thank you for watching and as always, Keep Looking Up!