In the berserk frenzy of thinking about situational very nuanced solutions to the Fermi Paradox
that I’ve been doing of late, here’s yet another one to contemplate.
One of the more intriguing, and compelling, newer solutions to the Fermi Paradox that
have come to the forefront in recent years is known as the phosphorus problem.
In a nutshell, the element phosphorus for several reasons seems to be rather scarce
in the universe and further it’s distributed in the galaxy in a rather spotty manner.
I prefer to refer to it as the phosphorus question however, the reason being that phosphorus
actually has several problems in several different ways including issues of water pollution and
a high dependence in agriculture that isn’t very renewable, but in the the framework of
the Fermi Paradox phosphorus is the one element, a chink in the armor of life, that if not
enough of it is present in a star system there doesn’t seem to be any way our brand of
life to get started and sustain.
Of course there may be other forms of biochemistry in the universe not dependent on this, just
our brand of life is.
For those looking for a deeper dive into the phosphorus problem itself I’ve linked to
a video I did that gives an overview, though now a little dated as I made it five years
ago, and a much deeper more recent dive done by my esteemed colleague Isaac Arthur.
But in thinking about the phosphorus problem and watching the developments in understanding
abiogenesis that have come out over the last two years, a realization hit me.
The phosphorus problem solution to the Fermi Paradox is actually much, much worse than
it’s normally been envisioned.
The phosphorus problem starts with supernovae.
When we look at supernovae remnants, not all of them are rich in phosphorus.
That would suggest that not all supernovae, even those seemingly in the same classes,
produce significant amounts of phosphorus, which in turn means that not all star systems
are going to be heavily seeded with this element enough for life to get going.
But here’s the problem, simply getting your star system seeded with phosphorus by a nearby
supernova isn’t the only step involved in getting it in a position for abiogenesis to
have enough of the element to be able to get going.
Our solar system got lucky, it has ample phosphorus or we wouldn’t be here, though levels do
seem to vary around the solar system and Earth’s levels are unusually high, even for the solar
system.
But it’s not unique to earth, phosphorus is found in meteorites, but also was recently
identified in the plumes of Enceladus, an encouraging sign for its liquid water subsurface
ocean to have the nutrients needed for life.
But a planet like earth merely having phosphorus in its crust is actually not enough for abiogenesis
so far as scientists can tell, but also once life gets going it’s possible at some point
to actually have too high of a concentration of nutrients, though that’s really more
of a problem for complex life and its relation to oxygen, a process known as eutrophication,
a very serious and growing problem in our world today and one way of how waterways get
polluted and messed up.
So the current thinking is that there must have been some other method of phosphorus
delivery to the planet that supplied a consistent, constant supply of bioavailable phosphorus
for life to use to get going.
The problem is, up until very recently, as in last month, there didn’t seem to be a
ready way for this to happen.
The natural suspect would have been the influx of meteorite and meteoroid material arriving
at the surface of the earth 3.7 billion years ago, which would have been significantly higher
than what it gets today.
Trouble is, the amounts of that possible at the time are not sufficient to have coated
the earth in enough phosphorus, so the meteoroid hypothesis never gained much traction until
recently.
Another long shot option is volcanism, more on that in a bit.
The recent work in question hypothesizes that there is one way to concentrate meteoritic
phosphorus on a planet’s surface and get it into a body of water, one option are highly
mineralized lakes, and the other is glaciers.
Glaciers, such as those in Antarctica, function at a certain level like a conveyor belt.
Indeed meteorite hunting scientists in Antarctica use this effect because as meteorites fall
on the ice, they get trapped, and transported across the continent to melt out at the edges
of the glaciers and deposit in convenient concentrated areas to be picked up.
As an aside, weirdly, there is a former mystery in this process only recently solved.
The scientists collecting meteorites in Antarctica noted long ago that they very rarely ever
find iron meteorites in the deposits.
The distribution is far below what we find on regular land.
So where are the antarctic iron meteorites?
Turns out that when they fall on the ice and are then subject to the unrelenting sun during
the 6 months Antarctica is in permanent daylight, the iron heats up and the meteorites sink
into the ice below the conveyor belt layer and then just sit there.
There are now plans for researchers to go down there with metal detecting equipment
and ground/ice penetrating radar to look for Antarctica’s iron meteorites and dig them
out.
But back to the phosphorus question.
The phosphorus in meteorites is specifically interesting because it comes relatively abundantly
in the form of the mineral Schreibersite.
This is interesting, because unlike most of earth’s phosphorus compounds, this one actually
will readily react with organic chemistry.
But you need to concentrate it somehow.
So to concentrate the phosphorus from the meteoroids, the idea is that you need a melt
pond at the terminator of a glacier collecting it up in addition to sufficient phosphorus
in your star system.
That’s two problems.
But there’s more, and here’s where it gets much worse.
You also need other factors to come into play.
I should note here that the abiogenesis hypothesis I’m following here works under the assumption
that it happened on land, which is the current favored scenario, but another solid scenario
is that it happened around an oceanic vent.
This cannot be discounted because these vents have been shown to also be a true geologic
source for phosphorus.
Trouble is, most of the rest of the ocean doesn’t have enough phosphorus, yet the
earliest evidence of life on earth is ocean related.
So if the process happened around those vents in the ocean, then this scenario goes out
the window.
So I have to caveat here, and leave that option open.
We just don’t know.
But recent discoveries on the land side of things paint a rather complicated picture
in that they show that certain aspects of abiogenesis were easier than we thought, but
the environment in which they can happen on land is actually very restrictive, almost
as bad as the ocean.
The first involves cell walls.
Work by Deamer and Damer, a link to an Event Horizon interview I did with Dr. Deamer in
the description below, showed that lipid proto cell walls can form in an environment where
you have volcanic hot springs periodically drying out or partly drying out, and then
rehydrating.
Dr. Deamer did experiments in the very volcanic Kamchatka Peninsula in Russia and found this
effect.
The other work involved here is another recent discovery by Stephen Benner involving just
how RNA comes to be, another link to his interview below as well.
This was a huge question in abiogenesis, one of the greatest ones, that spawned numerous
hypotheses about just how you get an RNA molecule to happen in nature.
Some of these even involved ideas like radioactive beaches, and all sorts of interesting ideas,
but in the end the answer seemingly was far simpler.
Randomly assembled RNA comes out when you percolate nutrient rich water through basaltic
volcanic glasses.
So put these three things together.
Glaciers, hot springs, and volcanic glasses and the picture starts to resemble a volcanic
mountain.
And, it has to be said, could enough phosphorus be produced by volcanic activity for the magic
to happen without meteoroids?
The problem that faces is that most of the phosphorus compounds thought to be around
at the time produced by volcanic activity were water insoluble and not available to
life.
There are three places where this kind of environment is known to have occurred, though
Venus remains up in the air on this count.
Obviously earth had it, and it still occurs, sometimes catastrophically.
One of the worst aspects of a volcanic eruption where glaciers are present are lahars, as
those glaciers melt during a major eruption as what happened at Mt.
Saint Helens in Washington state in 1980, huge amounts of water and wet volcanic ash
came rushing down the river systems around the mountain to devastating effect.
We also see this environment with Mars, which has enormous volcanoes that very likely once
hosted glaciers as well.
And we know from the Martian meteorites that it has plenty of basaltic glasses, and very
likely had hot springs when it had surface liquid water meaning that Mars remains a very
good candidate for once hosting the conditions for abiogenesis, and perhaps that might have
happened.
We just don’t know.
The third candidate is Io, which remains volcanic, but early in its history it’s thought to
have had as much water as Europa and the other Galilean moons, thus it too at one point in
its history seems to have had the ability for abiogenesis to occur in principle, but
you also have to account for Jupiter’s massive radiation torus which might have not allowed
for the process at least on the surface.
So not only do you need phosphorus, but you also need either a volcano with the right
glacier, resulting melt lake, volcanic rock and hot springs in proximity and contact with
that lake, or you need the right conditions which are still very murky, pun intended,
around an oceanic hydrothermal vent.
All of those factors together could constitute a rare enough of a situational environment
as to constitute a solution to the Fermi Paradox above and beyond just the phosphorus problem
alone, in that the chemical soup and conditions needed for abiogenesis to occur is somewhat
rare to begin with.
In fairness, we don’t fully understand the process of abiogenesis yet, but the environment
alone and the phosphorus delivery and concentration issue might be a major factor that precludes
it from happening very often.
Adding another dimension to this is the Miller-Urey experiment.
There, the nutrients were added in a glass container, which was then subject to electricity.
Out came sugars, and all sorts of compounds life uses.
But that experiment relied on using an electric arc specifically to simulate lightning, so
you might also need to factor that into our volcanic lake scenario.
It might have had to be struck by lightning regularly enough to provide even more of the
constituents of life, but that’s not really a big problem because volcanic ash clouds
can produce lightning, and so can weather.
A potential problem for this rather situational and convoluted solution built on top of the
phosphorus question is that we don’t actually know if Earth 3.7 billion years ago even had
any glaciers.
This is going to be difficult to establish because almost nothing geologically is preserved
from that time period on that level.
We’ll need to try to learn more through atmospheric science and attempts to reconstruct
the conditions back then to infer the existence of glaciers that early.
And it has to be noted again, that this scenario doesn’t really apply to the oceanic vent
hypothesis, which is still in the running.
There the phosphorus problem seems to simply stop at the supernova question.
If a planet gets seeded with phosphorus, that phosphorus comes back out at the geothermal
vents.
But only if you have enough phosphorus in your geology to begin with.
Lightning, volcanos, glaciers, oh my.
And the right kind of rocks.
All with a supernova close enough, and of the right type, to provide the phosphorus.
And that’s just to get to the conditions needed for life to arise, there doesn’t
seem to be any clear guarantee though under those conditions that it will happen every
time.
If those conditions for example don’t persist long enough, which for all we know might be
centuries or more, or might be overnight, then it may not happen.
Or it might happen every time those conditions present themselves, we don’t know.
But even if it does, then there is a further problem.
And that is the litany of other solutions to the Fermi Paradox that come into the picture
once life arises, such as the prokaryotic to eukaryotic leap, the development of photosynthesis
or lack of that ever happening, and so on that may further limit what life can do.
When you put all of that together though, and I hate to say it, but the great silence
isn’t so deafening any longer, and starts looking like an expected outcome and status
quo for the universe at its current age.
Thanks for listening!
I am futurist and science fiction author John Michael Godier currently apologizing to the
volcanic hydrothermal vents.
As much as we can study the potential for abiogenesis to occur on land, there are always
those vents and if you think about it, it opens up a question.
What if there are actually two ways for abiogenesis to happen?
One on land, the other at the vents.
If that’s the case, then it very much changes the game and the paradox comes back in full
force 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.