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Life.
As of yet, there is only one example we know of – the life we find here on Earth.
There is no definitive proof of life anywhere else in the universe.
But that does not mean for certain that it’s not out there.
If there is alien life on planets other than our own, what might they look like?
What would be their biology, and what would we see of their civilisation?
You might think that there is no way to predict this.
However, believe it or not, even though we have never seen a single alien, we can make
educated guesses based in science to help us know what to expect.
And it’s all thanks to a simple principle: Form Follows Function.
I’m Alex McColgan, and you’re watching Astrum.
And although we cannot say with exact certainty what any aliens visiting us might appear like,
or how they behave culturally and technologically, today I’m going to share with you some ideas
that might mean, if they do ever land on our doorstep, you aren’t completely caught off
guard.
But first, let’s talk about why we look the way we do.
As you look down at your own body, even if you do not know what all of it does, you are
an incredible example of optimisation.
You likely have two hands complete with fingers and opposable thumbs, ideal for grasping tools
and performing fiddly, delicate operations.
You have a digestive system that is capable of taking in matter, extracting nutrients,
and using them to build up or repair yourself.
You have legs for locomotion.
A brain for thinking.
A heart that will on average pump 2.5 billion times across your lifetime without breaking.
All of these parts of your body perform specific functions, that have been honed over millennia
to be really good at what they do (even if you don’t feel it sometimes).
You are an example of form following function.
Thanks to natural selection and random mutation, nature is really good at figuring out what
works.
When Charles Darwin was voyaging through the Galapagos Islands, he noticed that different
finches had different shaped beaks.
After observing them for a time, Darwin noticed that the finches with larger, more heavy-set
beaks ate different types of food than finches with smaller, daintier beaks.
In fact, a large beak was ideally suited to breaking open tough seeds or nuts, while the
smaller beaks were more suited to getting in nooks and crannies for grabbing insects.
This observation was the basis for his well-known theory of evolution.
In this theory, thanks to genetic variation and competition, nature is constantly trying
out new things to see what works.
And there are certain things that give you an edge.
For instance, thanks to all the light that was bouncing around from our Sun, organisms
that evolved to take advantage of this by developing sight had a big advantage over
organisms that did not.
They could find food better, or avoid predators, or generally navigate their environment.
So useful is sight, that nature did not just come up with it once.
We believe the eye evolved independently about 40 times over the course of life on Earth.
40 different species that previously could not see evolved eyes.
This is called convergent evolution, and eyes are not the only example of it happening.
Bats are not related to birds, and yet both developed wings to fly.
And speaking of bats, both bats and dolphins independently evolved echolocation, to help
them see in environments where light was not so plentiful.
Photosynthesis has arisen dozens of times.
Koalas have almost identical fingerprints to humans.
This happens because there are some selective pressures that are simply universal.
Everything that lives needs to gain nutrients, grow, and reproduce, and as a result, like
a plant bending its roots around rocks to find softer soil, nature is good at figuring
out the best way of getting what it needs.
Because of the prevalence of light, eyes are just a good idea.
And when something works, nature sometimes comes up with it more than once.
This means that on planets that are similar to our own, it’s entirely possible that
evolution would end up going a similar way.
Although hypothetical aliens on other planets might not look exactly like us, they might
look surprisingly similar.
I always thought that it looked silly that so many aliens in sci-fi films were humanoid,
but perhaps this is more than just a way of easing pressure on the film’s costume department.
Convergent evolution says this might actually happen.
If it worked with us, maybe it just works generally.
Any alien that made it to the stars would need to have the ability to work tools.
So, fingers, or something similar, would be a likely addition to an alien race.
Large heads filled with complex brains for analysis and problem-solving would also be
a benefit.
The human brain is the most complex of any animal’s on earth, with 86 billion neurons.
It’s not so unreasonable that aliens would be the same.
Thanks to our brains, it became less important to keep ourselves warm with fur as we could
craft clothes for ourselves, so aliens may not be hairy or thick skinned if they are
intelligent.
Of course, this kind of logic might not carry all the way, because life might not arise
on a planet that’s exactly the same as ours.
If there are different selective pressures, different adaptations might occur.
For instance, on a planet with low gravity, plants and animals would be able to grow to
be much taller than on Earth.
There would be less energy cost to lifting nutrients up through their bodies, or pumping
blood around (if aliens used those kinds of systems).
While conversely, on a planet with very high gravity, you’d likely see stockier, shorter,
heavier-built aliens.
Their bones would need to be denser to support themselves in heavier gravity.
Or possibly they would be aquatic, as gravity is less of a problem in water.
On a planet that is further out from its star than ours, there would be less light, so an
alien’s eyes might be bigger.
Or maybe aliens on such planets would rely on things like echolocation to see what is
around them.
On planets with elliptical orbits, seasonal temperatures would vary much more wildly.
Perhaps on such planets you’d see an increase in the ability to hibernate, or even come
back from near death, such as tardigrades and their incredible ability to return to
animation after being in the harshest of environments like the depths of space.
Temperature can also affect size, such as in the depths of our oceans there occurs deep-sea
gigantism, as large bodies can more efficiently be kept warm, while in deserts small animals
have a larger mass-to-surface-area ratio, allowing them to disperse heat more effectively.
On a planet with fewer magnetic fields, more bombarded by cosmic radiation, perhaps life
would have shorter life-spans, in much the same way as around the heavily irradiated
Chernobyl nuclear power-plant, dogs and other short-lived organisms thrive, while longer-living
humans suffer.
In each case, form follows function.
Life will adapt to suit the conditions it finds itself in.
And it doesn’t end there.
Did you know that this logic can apply to cultures and civilisations too?
When the Spanish conquistadors met the Aztecs, there was a significant technological gap,
in spite of both groups being humans.
Some historians hypothesise that this can be linked to things like the ease at which
each group could farm.
Intensive crops that require a lot of effort to grow require more of the population to
spend their time farming, leaving fewer individuals free for invention and scientific pursuits.
There are likely many other factors at play too, but environment is certainly one of them.
Prevalence of coal or other fuel sources could spark an industrial revolution.
The presence or absence of silicon or rare metals might help or hinder a computer revolution,
speeding up or slowing down a civilisation’s progress.
Once an alien race has evolved to the point where it has become intelligent, unless it
came into being through some weird mechanism we don’t understand, it probably did so
through out-competing its rivals and collecting resources for itself and its offspring.
Civilisations made up of such creatures will most likely also have a hunger for space and
resources.
Whether they gain these things through clever diplomacy or aggression, it is most likely
that they will want them.
Form follows function.
This quest for expansion and seeking more and more energy and resources led soviet astrophysicist
Nikolai Kardashev in 1964 to propose the Kardashev scale for classifying the different kinds
of alien civilisations that might exist out there.
He grouped civilisations into three kinds.
Type 1 civilisations can completely utilise the energy available on their planet.
We have not quite reached this point as a species, so we are roughly a 0.7 on Kardashev’s
scale.
Type 2 completely utilise the energy available from their star, possibly by building a giant
mega-structure such as a Dyson sphere to capture and utilise all of its energy output.
Type 3 civilisations would be able to utilise the entire energy output of its galaxy.
We have seen no evidence of an alien civilisation such as this one, which is for the best, as
they would likely see us in the same way we see bacteria – mildly interesting, but otherwise
completely beneath their notice.
Other scientists since Kardashev have proposed further additions to this scale – type 4s
that use all the energy in the universe, type 5s that use all the energy in multiple universes,
or even the enigmatic Type omega, capable of utilising energy sources beyond even that,
perhaps existing outside of time entirely.
Such a civilisation would essentially be gods.
We would have no way of detecting them, because nothing in this universe would exist except
in the way they wanted it to, and we would have nothing to compare their existence against.
While this may seem like a bleak outlook for humanity – if ever we come across another
race, under this theory we would almost certainly end up competing for resources in one way
or another, or just getting steamrolled by a vastly higher power – there actually are
other possibilities for alien development too.
After all, not all humans are interested in expanding ever outwards.
In fact, with the advent of the internet and online cyberspace, more and more human interaction
is taking place in virtual spaces.
Carl Sagan proposed a model that classifies alien races based on how many unique pieces
of information they collectively know.
Although much harder for us to detect at a distance, and admittedly hard to measure,
this way of gauging advancement does not require an alien race to infinitely expand.
An intelligent race that started looking internally, or even one that spent its entire conscious
time in some kind of cyberspace could still learn more and more about itself and the universe
as a whole, while taking less and less space within that universe.
For the record, Carl Sagan’s scale is alphabetic, where we were at about a type J civilisation,
as we apparently knew 1013 bits of unique information in 1973.
While I haven’t been able to find out exactly how he worked out that figure (mention in
the comments if you know), we are probably further along this scale now, 50 years on.
But as a comparison, a Z type civilisation would need to know 1031 bits, more information
than exists in the whole universe, so it’s unlikely that such a race exists, at least
not yet.
Ultimately, we do not know for sure.
Alien life continues to remain elusive.
But while it’s true that we have not met an alien civilisation, it is comforting to
know that it’s entirely plausible there would be something about them that we could
understand, and even find relatable.
Form follows function.
We as humans are the beings that think and gain mastery of our world.
Perhaps one day, if we meet another race that does the same things we do, rather than seeing
something truly alien, it perhaps will be like looking into a mirror.
I’ll leave it to you to decide whether that is a comforting thought or not.
Speaking of alien worlds, something I’ve been very much enjoying recently is having
a rotating globe of Jupiter on my desk.
It catches my eye every time I look around the room when I’m looking for inspiration,
because it’s gently moving on its axis.
Incredibly, it is powered simply by ambient light and Earth’s magnetic field, thanks
to some carefully placed magnets within the globe itself.
This means it’s very elegant, there are no cables to distract.
If you want one or think this would be a great gift for someone you know, check out my link
in the description below and use the code ASTRUM at checkout for 10% off their 6- and
8.5-inch models.
You can pick from a variety of designs, including maps of Earth, other planets and moons.
I highly recommend checking it out.
Thanks for watching.
Subscribe so you don’t miss the next episode, where we discuss what alien civilizations
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All the best, and see you next time.