
Can a Living Creature Be as Big as a Galaxy? - dnetesn
http://nautil.us/issue/51/limits/can-a-living-creature-be-as-big-as-a-galaxy-rp
======
stareatgoats
The question is not correctly formed: what we really want to know is if there
are life-like beings that could operate on a totally different scale than ours
(both time and size wise, including viruses and whales here). Self centered
thinking, i.e. restricting our inquiry to only include protein-based lifeforms
or other qualities required on our scale obviously prevents us from having the
required open minded mindset.

~~~
Consultant32452
There are more bacterial cells in your body than there are human cells. Where
exactly do you draw the line between what constitutes "you."

~~~
delecti
A zoo is still a zoo if there aren't any animals in it, but it wouldn't stay
in business very long. No matter how important the animals are to the long-
term viability of the zoo, they are not the zoo.

My gut bacteria may be vital to my survival, but they are not me. I don't find
placing that line to be difficult at all.

~~~
fattire
> A zoo is still a zoo if there aren't any animals in it

Is it? Identity is an interesting thing. To use a commonly-cited example-- if
I swap out the muffler of my car and toss the original in the backyard, I
think most would say I am still driving the same car. If I do the same with
the front left tire, it's still essentially my car. Even if replace all four
tires, same. But what if I swap one part a day with a replacement, after a
while I'll have all my original car parts in the backyard-- and am in effect
driving a car made of totally new parts, but is this still the same car? If
not, when would you no longer say it's the same car? And, if I assemble the
collection of gradually discarded parts sitting in the back yard into another
car-- now what? Which is my car? The thing I'm driving or the car made of the
old parts? Or are they both the same car?

Am I _really_ the same person I was when I was 10 ...or 10 months? What is the
"me"-ness, or are we talking about a different person? Where's the line...

Or... when Captain Kirk uses the transporter-- his molecules are
disintegrated, and then a copy of him gets assembled on some planet (using
local materials I believe)... So is "he" transported, or is he being killed
and replaced with an exact copy? (I think this question made its way to a
Breaking Bad episode)

Anyhoo. Is a zoo without animals in it still a zoo? I dunno.

~~~
oAlbe
Well, technically speaking, at least for a car, you can draw a pretty clear
line. Your car is your car because it is registered in your name through a
number soldered on its frame. Changing the frame would change that number and
you wouldn't be driving the same car, at least from a legal point of view.

But yeah, is a zoo without animals still a zoo? Hard to say. Even without
animals, a zoo would retain its potential to be a zoo. Meaning that you could
put animals in it and would be back to being a zoo. Same thing can't be said
about a restaurant, for example. You can put animals in a restaurant, but
regardless of how good you can lock them in it's still not a zoo.

~~~
TheOtherHobbes
It's hard to say because it's not a yes/no question, and the most useful
answer is going to be very context/state dependent.

A zoo isn't a collection of animals - it's a social, financial, and cultural
structure with associated buildings, signage, web site, and staff, that
_usually_ houses animals.

If you lose the animals temporarily, you can keep the rest and still have a
zoo. (This has actually happened during wartime evacuations.)

If you lose everything, you have a former zoo.

We have minds that put simple labels on complex relationships.

------
tsunamifury
It's answer of "No" is predicated on two assumptions: that the lifeform is not
colonial in nature and that time is not a localized phenomenon. While on the
surface that later assumption might sound absurd, our universe could very well
be a Local Bubble of time. Time could even be a biological function of a
higher dimensional being that is the size of the universe. There is also no
way to disprove that without observing beyond the universe, which may get a
bit dicey.

~~~
eljimmy
Thinking about what exists outside the universe always makes my brain feel
weird. It seems impossible for your thoughts to imagine anything because your
thoughts themselves are bound by the universe itself.

~~~
komali2
Well even worse, our thoughts are bound by some maximum distance of
comprehension. We can abstract the stellar scale but we can't understand it
like we understand the distance across the street or whatever. I find this
frustrating :(

~~~
ztjio
Well I think the implication that we can't understand/comprehend these things
is itself frustrating and also wrong. Why does one assume that the scale of
the universe and the scale of that street you refer to are any different? In
both cases you are experiencing and considering an estimation of potentially
infinite space at an almost metaphorical level as it relates to your
experience, plans, and actions.

Indeed, you can consider the universe as this thing which is maybe boundless
and has _so much stuff_ and _might go on forever_ but for some reason you
think it's any harder than realizing that the street may be _infinite in
space_ as well, by virtue of continuous subdivision. Before trying to dive in
on any estimate of the smallest thing, do remember that smart people once
thought atoms were the smallest thing, and then particles, and so on. And
remember that the street itself, even just the stretch you're concerned about,
is composed of a ludicrously large number of the "smallest" things we current
are aware of.

If we let go of this idea that at our own size, things are just some number of
things that we can reason about (since that's clearly false, do you reason
about the billions of living organisms in your own body right now? Could you?)
then we can start to realize that smaller or bigger, we're merely consider a
continuum at different scales and it's perfectly reasonable for the human mind
to do so, it does so every day all the time.

~~~
komali2
I was thinking along the lines of evolutionary biology - I'm assuming my human
brain is only capable of truly processing scales that realistically my
ancestors would experience.

------
bitL
We still don't know if the Universe itself isn't a living organism with us
playing the role of tiny viruses that require intelligence/consciousness to
fulfill certain tasks, like what gut bacteria does for us.

~~~
banachtarski
We do. If you bothered to read the article, it makes a point that the
communication speed between the components would be slow enough (even at light
speed signaling) that the age of the universe would not have permitted
sufficient time for such an organism to evolve and do anything.

~~~
paradite
Well, maybe the age of universe is indeed "too short" for it to do anything
useful yet? Your argument seems to be supporting the idea that the universe is
like a baby who is still too young to do anything.

~~~
banachtarski
I mean, before humans, there were eukaryotes, and prokaryotes before them. My
argument is not supporting that the universe is a baby. It is saying that the
being does not exist because it could not have evolved on this timescale, in
the same way that single celled organisms are not human babies.

~~~
Taek
If we assume that the big bang was actually the conception event of some other
cosmic entity, the universe could very easily be a living organism that's the
equivalent of a few microsecond old fertilized zygote.

So yes, a universe sized lifeform could not have evolved randomly since the
big bang, but you can only be confident about that if you assume that nothing
exists outside the spacetime bubble we call the universe.

~~~
jfoutz
or it could be the big bang is the relaxing of a muscle cell is some cosmic
monster. Or perhaps the big bang was kinda like enzymes, breaking something
hard to eat into a nice easily digestible heat bath. or it could be an edge
transition of one wire of some cosmic computer.

It's fun to kick around crazy ideas on Saturday afternoon. It could be
anything. Sadly, there's no way i'll ever know. But the idle speculation is
still amusing.

~~~
meric
Or, you can write a science fiction short story and make it true in a
fictional world you invent.

------
mirimir
It's a thoughtful article, and I love the reference to Burroughs' _Soft
Machine_. But it doesn't distinguish clearly enough between self-conscious
organisms and the rest. It's true that consciousness and evolution thereof
likely crap out when latency goes over a few hundred milliseconds.

However, I see no limit to the size of zero-gravity organisms like the honey
fungus. Fungi are filamentous, so there's no unsurmountable problem with heat
dissipation.

And even for self-conscious organisms, I can imagine hierarchical
organization, such as Rajaniemi's "metaself" or Watts' Bicameral Order.

------
Koshkin
Since proteins cannot exist in space, then, using the currently accepted
definition of "life" at the basic level as the complex of processes that allow
protein molecules to exist, then the answer must be 'no'.

On the other hand, it is an interesting mental exercise to also consider other
reasons why such creature might be impossible. One reason could be because the
time needed for such creature to grow from something much, much smaller (as it
usually happens in biology) would be longer than the age of the universe.

Another one is that nerve impulses travel slower than the speed of light, and
so, again, it would take forever for a signal to reach the central nervous
system. One could argue that the creature can be "decentralized", i.e. look
more like a large colony of smaller organisms, but then the question arises as
to what makes it a single creature in the first place.

Yet another issue concerns what drives the evolution of this particular
species, and, again, the time it takes.

So far, all these considerations unavoidably lead to the answer 'no'.

~~~
laumars
There are animals on Earth with a decentralised nervous systems (most famously
the octopus) and there isn't any confusion about whether they're classed as
one animal or multiple ones.

~~~
Koshkin
Octopus does have the "central brain" though - which, I guess, may account for
making it "one animal". On the other hand, an animal with a truly
decentralized nervous system often can regenerate from its pieces, which makes
the question of it being "one animal" in the first place a bit fuzzy.

~~~
21
There was an article just yesterday on HN about such a creature, with a
decentralized nervous system:

> Ctenophores have no brain or central nervous system, but instead have a
> nerve net (rather like a cobweb) that forms a ring round the mouth and is
> densest near structures such as the comb rows, pharynx, tentacles (if
> present) and the sensory complex furthest from the mouth ... Ctenophore
> nerve cells and nervous system evolved separately from other animals and
> have a different biochemistry.

------
axplusb
I'm surprised to find no mention of Solaris by Stanislaw Lem among the fiction
references. In this novel, a whole planet is somehow a living organism, truly
alien to human conception of life.

~~~
mrdrozdov
An excellent read! I had the same thought. It's almost negligence not to
mention it.

------
dwaltrip
A bit of tangent -- the article talks about powers of ten, and hints at how
_powerful_ a tool it is for analyzing everything around us. This resonates
very strongly with me. The entire known universe, from the smallest particle
to the width of the cosmos itself, fits within several dozen points on this
scale. It's incredible.

Personally, the last few years, I have felt that working to understand how all
phenomena can be sketched out on the log scale has helped me gain a deeper
understanding of the world. Of course, this goes hand in hand with related
ideas, such as having a generally skeptical mindset, seeking first principles,
etc.

These ideas has been very powerful for me, and I thought it might be worth
sharing.

P.S. the book "The Black Cloud", mentioned in the article, is a really fun and
quick read. I recommend it for any sci-fi fans.

------
kindadumb
This theory was once proven in a famous documentary
[http://www.youtube.com/watch?v=AJOVUF-
HaDw&t=0m37s](http://www.youtube.com/watch?v=AJOVUF-HaDw&t=0m37s)

------
hypertexthero
> Stars are best regarded as living organisms, but organisms which are
> physiologically and psychologically of a very peculiar kind. The outer and
> middle layers of a mature star apparently consist of “tissues” woven of
> currents of incandescent gases. These gaseous tissues live and maintain the
> stellar consciousness by intercepting part of the immense flood of energy
> that wells from the congested and furiously active interior of the star. The
> innermost of the vital layers must be a kind of digestive apparatus which
> transmutes the crude radiation into forms required for the maintenance of
> the star’s life. Outside this digestive area lies some sort of coordinating
> layer, which may be thought of as the star’s brain. The outermost layers,
> including the corona, respond to the excessively faint stimuli of the star’s
> cosmical environment, to light from neighboring stars, to cosmic rays, to
> the impact of meteors, to tidal stresses caused by the gravitational
> influence of planets or of other stars. These influences could not, of
> course, produce any clear impression but for a strange tissue of gaseous
> sense organs, which discriminate between them in respect of quality and
> direction, and transmit information to the correlating “brain” layer.

From Star Maker by Olaf Stapledon, Chapter 11, Stars and Vermin

[https://ebooks.adelaide.edu.au/s/stapledon/olaf/star/chapter...](https://ebooks.adelaide.edu.au/s/stapledon/olaf/star/chapter11.html)

------
alexpetralia
Does a group of people have an emergent consciousness in its own right that no
one person can individually experience?

Perhaps certain parts of the brain too "think" they are conscious but can't
individually experience the same consciousness we as people experience.

------
jeffdavis
Related: On Being the Right Size

[https://irl.cs.ucla.edu/papers/right-
size.html](https://irl.cs.ucla.edu/papers/right-size.html)

------
Poc
It make me think of Von neuman probe. If we can consider that a robot or
something with connections similar to our neurons can be a living creature.
Then maybe if something like Von Neuman probes existed it could have colonized
the whole galaxy (actually it could be done in a few hundred millions years)
then those probes, while each one have is own brain, could communicate with
the other probes and even if two probes at two opposite sides of the galaxy
couldn't communicate, they would still be connected. Then maybe this network
could be consider as a living creature.

------
Balgair
Quick reminder: We don't know what the majority of the mass/energy of the
universe is. Dark matter is ~20% of the universe and pretty much all we know
about it is that 'it falls down'. Dark Energy is ~75% of the universe and all
we know about it is that it makes galaxies accelerate away from each other.
So, defining life or intelligence as we do is maybe not the best idea for long
term thinking.

~~~
bhldr
The ocean is mostly water, so hypothesizing the size of a whale is not the
best idea for long term thinking.

------
visarga
When thinking about such things, you've got to ask yourself: under what
circumstances would such a creature appear and under what circumstances could
it die? What does it need? What constitutes a good or bad thing for it. How
does it learn? How does it perceive? How does it act out its intentions? Does
it have a self preserving instinct?

It doesn't make much sense for a creature the size of the galaxy. If it did,
it would be extremely slow and alien to us.

A more plausible way would be if a human-scale civilization would create self
replicating probes that would spread in the galaxy and bootstrap some sort of
large biological or AI civilization.

------
SCHiM
I love topics like this :)

If yes, the next question might be:

> Imagine a creature that is as big as the galaxy, imagine its organ that is
> analogous to our brain is as efficient and big as is possible, what is the
> most complex concept that that brain can fully comprehend?

------
11thEarlOfMar
It's a different topic, but related. I was marveling at the diversity of life
on Earth, which led me wonder: to what extent does sustained life on Earth
depend on that diversity? I.e., what would be required or different for a
planet to host and sustain a single species of life?

Given the nature of evolution, and that one subscribes to it, life on Earth
started with a single organism that replicated. From that point until a
replication modified the organism into a different species, there would have
been one species. But was it necessary to have multiple species in order to
sustain life?

~~~
heckerhut
Yes. Evolution is actually its own evidence. Biological evolution evolved out
of necessity. Without constantly changing evolutionary pressures exerted by an
organism's external environment there would be no need for evolution and it
therefore wouldn't have evolved.

~~~
idlewords
That's the opposite of an evolutionary argument. Evolution is not
teleological, it doesn't arise to meet a need.

It's a kind of feedback loop in low-entropy systems that given enough time can
produce interesting phenomena, including this message board.

------
sriku
"Exhalation" by Ted Chiang is, I think, a great literary exploration of this
topic and brings the essence of what is required for life, though it doesn't
get into what life is as opposed to other phenomena. For those who've not read
it, I may be giving off too much if I said anything more.

It is certainly more insightful (again imho) than this article.

[http://www.nightshadebooks.com/Downloads/Exhalation%20-%20Te...](http://www.nightshadebooks.com/Downloads/Exhalation%20-%20Ted%20Chiang.html)

------
andy_ppp
Sort of tangentially related is the physicist Geoffrey West, who decided to
try to apply the thinking of a theoretical physicist to biological systems.
His book Scale is excellent, and this is one of the most interesting podcasts
I've ever heard:

[https://www.samharris.org/podcast/item/from-cells-to-
cities](https://www.samharris.org/podcast/item/from-cells-to-cities)

------
cardigan
Hmm, but what if the living creature had a density of neural circuitry similar
to ours, and mainly interacted with things inside itself, and had slow
propagation of knowledge? Not sure I understand this except under the hidden
assumption of having a similar number of neural circuit elements

------
FrozenVoid
The comparison about surface areas is wrong. A creature could drastically
increase its surface area by having many tendril-like appendages (i.e. hairy
surface) and limiting the core body to consist of thin shapes. A fractal web
of tendrils would dissipate energy far more effectively.

~~~
DonHopkins
[https://en.wikipedia.org/wiki/Elder_Thing](https://en.wikipedia.org/wiki/Elder_Thing)

------
rcthompson
If anyone is interested in a sci-fi novel series that explores these kinds of
themes for intelligent life, I highly recommend Ancillary Justice by Ann
Leckie. (I've left the statement above intentionally vague to avoid excessive
spoilers.)

------
nils-m-holm
Why only as big as a galaxy? Why not the entire universe?

[http://www.geoffreylandis.com/infinite.htp](http://www.geoffreylandis.com/infinite.htp)

(Geoffrey Landis, the Melancholy of Infinite Space)

------
asah
re heat dissipation - the author assumes a mostly-convex form, but if the life
form as concave spaces (e.g. tentrils) then the surface-area-to-volume ratio
can be arbitrary.

------
sebastianconcpt
Aren't creature body sizes a function of some combination of food size and
quantity? If so, what this hypothetical creature would eat?

------
brunomarx1
What if the galaxxy itself were a living being, but we are so small to grasp
this form of life

------
swarup182
may be galaxy on itself is a living creature, and we are just like neurons in
it. or cells.

------
jfoutz
So this requires a few things,

First off, single organisms can have pretty advanced local processing of
control. An octopus has a nerve cluster for each tentacle that can operate
independently of the main brain [1]. So in at least one case, biological
brains delegate work out to another region of the body. An argonaut octopus
actually detaches part of it body, which as far as i can tell, keeps living
for a while. it's kind of creepy. The only thing i can't find an example of,
is remote control. A detachable body part, with a nerve cluster, that responds
to light or sound seems like what would be needed for the base creature.
Evolution hasn't stumbled on that trifecta here on earth. But it sure seems
like something that could have come about.

The latency argument isn't compelling. If i can send one message, i can send
another hundred billion messages along with it. So, sure only a few thousand
round trips, but a fabulous amount of information transferred. There's no
actual biological equivalent to a semi autonomous drone, so i'm not sure what
that would look like before the creature took to the stars.

There's also no real obvious way for this lone detatched tentacle to consume
the resources of a planet. But whatever. I think one entity with those three
features might have a chance.

Also, is the creature smart? Does it get to genetically engineer itself? do
cyborgs count? That greatly simplifies things as well. The detachable parts
could have detachable parts, and recurse down to whatever arbitrary degree is
useful.

Alternatively if you admit superorganisms, then everything is much easier.

So anyway, you don't really need to send many messages when the message is
"here are the latest designs for industrial architecture to dismantle a solar
system and send the resources back" It's up to the billions of lone tenticles
and their machines to execute the will of the super brain.

On the other hand, yeah, there's not going to be a galaxy sized amoeba or
panther or anything like that. maybe an incredibly fine mist of fungus or
mold, but i think it'd be too hard to keep a system like that from collapsing
in on itself from too much mass. a galaxy sized ring of spider silk orbiting a
black hole sounds like great science fiction. but i can't imagine that
working.

[1]
[https://en.wikipedia.org/wiki/Octopus#Nervous_system_and_sen...](https://en.wikipedia.org/wiki/Octopus#Nervous_system_and_senses)
[2]
[https://en.wikipedia.org/wiki/Argonaut_(animal)#Sexual_dimor...](https://en.wikipedia.org/wiki/Argonaut_\(animal\)#Sexual_dimorphism_and_reproduction)
[3]
[https://en.wikipedia.org/wiki/Superorganism](https://en.wikipedia.org/wiki/Superorganism)

------
baron816
Challenge accepted

------
mcappleton
Look, the vast majority of a galaxy is empty space. A living creature is
obviously not empty space, so all that space would have to be filled with the
creature's matter. Well, if you put that much matter so close together, it
will all collapse on itself and create a black hole.

So no, you could not have a living creature as big as a galaxy.

~~~
philovivero
Uh. The vast majority of what constitutes YOU is empty space.

Sometime go look up the amount of space between the protons, neutrons, and
electron cloud in an atom.

~~~
mcappleton
The center of every galaxy is a black hole. Lol so the center of this creature
would be a black hole?? Some weird creature

------
devoply
This article does not take into account quantum phenomenon. It's possible that
instead of being limited by the speed of light transmissions, such a system
uses quantum phenomenon for communication. Which then would make the whole
argument that this article makes invalid. It's based on the premise that life
would be based on the same sort of physics as life on Earth... which does not
make sense as such life if it exists would evolve using a different set of
rules which would include things such as limits on speed of light transmission
in such large systems... so it would've learned to exploit quantum phenomenon
for transmission.

edit:

Superluminal, or faster than light, communication is said not to work because
it allows information to be sent into the past. There is however non-locality
which is not the same thing. Sorry not an expert on this, but this seems to
apply to the exact discussion.

[https://en.wikipedia.org/wiki/Bell%27s_theorem#Importance_of...](https://en.wikipedia.org/wiki/Bell%27s_theorem#Importance_of_the_theorem)

~~~
danharaj
There are no quantum effects that allow superluminal communication of
information.

~~~
Cozumel
Sure there is. You've just not seen it on HN yet.

