Did the universe evolve?
I think the universe my have itself evolved. It sounds mad, but bear with me.
The universe kicks off with a bang, and it starts very simple. Just a soup of the simplest type of atom. Then stuff bumps into each other at random, and begins to clump together. Things keep bumping into each other at random for about 13.8 billion years, until you get clumps who are called Rob writing essays on computers that are all networked together.
Okay, not quite. Things bumped into each other at random at first, but then around 3.5–4 billion years ago, things bumped into each other randomly in the right way to create self-replicating organisms that then evolve. Then evolutionary pressures tend to create beings of ever greater complexity, until you get things called Rob writing essays.
Yet the universe seems to tend towards greater complexity over time from right the start. From a soup of the simplest atoms to stars, planets, oceans, and then bacteria, trees and sentience.
Inert objects tend to decay over time, becoming less complex. But over time the universe gets ever more complex. In that regard, it’s more like an egg than a rock. That’s the name of a Substack (and upcoming book) by Julian Gough, which proposes that the universe evolved and that the fact it evolved explains many things about the universe.
It’s a big claim. I’m not 100% sold on it, but I am highly intrigued. So I’d like to lay out the arguments for this point of view (most of which is just summarising Julian’s arguments), and offer my own thoughts.
The mechanism: Black holes
Before we get to the evidence for this position, first, it’s necessary to explain what is meant by the claim that the universe evolved. Evolved from what? — is the obvious next question.
The theory starts by suggesting that the universe exists inside a black hole.
We know the universe started from a point of singularity exploding outwards (the Big Bang). What else is a singularity? A black hole. A point of infinite density, inside of which the known laws of physics break down.
The idea that the universe is inside a black hole was first suggested by I J Good. He’s the chap who originally thought of the concept of an intelligence explosion, which is also known as ‘the singularity’. Nothing is ever a coincidence.
Intriguingly, the Hubble radius of the observable universe is potentially almost exactly the same as its Schwarzschild radius, which is the size a black hole would be if it had the mass of the universe. Some physicists think this is just a coincidence. Nothing is ever a coincidence.
According to this paper: “Using present-day estimates of the size and average density of the observable universe, its Schwarzschild radius is found to exceed its physical radius. This means that, if the observable universe is a representative part of a material universe included in a larger space, this material universe should be a black hole”.
This idea that the universe might exist inside a black hole is hard to prove, but it’s certainly possible.
So, if universes ‘birth’ more universes by creating black holes, then universes whose laws of physics lead to more black hole formation would have more offspring. If universes have similar laws of physics to their parent universe, but with some ‘mutations’ (some random changes in the laws of physics), then this would mean universes ‘evolve’ over time to have laws of physics more attuned to black hole formation. This theory was first proposed in 1992 by American theoretical physicist Lee Smolin.
In the Egg and the Rock, Julian Gough goes one step further than Smolin, and suggests that this process of cosmological natural selection ends up selecting for universes that create life, because sufficiently advanced intelligent life would create black holes.
Evidence for the theory
We’ve established our universe could be in a black hole, (its Schwarzschild radius exceeds its physical radius), but what would make us think that the universe is the result of some form of ‘cosmological natural selection’ that’s selecting for universes that produce more black holes?
There are at least three key arguments for why this would be the case:
Loads of natural laws are ‘just right’ for complexity and life
The universe starts forming complex structures faster than anticipated, e.g. Star formation kicks off really early. These structures optimise for the production of ever more mass-efficient black holes.
Life happens near the start of the timeline of the universe
Natural laws are ‘just right’
There are lots of fundamental laws or properties of the universe which are ‘just right’ for complex structures to form and to allow life to exist. This is known as the fine-tuned universe.
Now quoting from Wikipedia: Stephen Hawking observed that “The laws of science, as we know them at present, contain many fundamental numbers, like the size of the electric charge of the electron and the ratio of the masses of the proton and the electron. … The remarkable fact is that the values of these numbers seem to have been very finely adjusted to make possible the development of life”.
Examples of laws of nature being seemingly fine-tuned for complexity and life include:
N, the ratio of the electromagnetic force to the gravitational force between a pair of protons, is approximately 1036. According to Rees, if it were significantly smaller, only a small and short-lived universe could exist. If it were large enough, they would repel them so violently that larger atoms would never be generated.
Epsilon (ε), a measure of the nuclear efficiency of fusion from hydrogen to helium, is 0.007: when four nucleons fuse into helium, 0.007 (0.7%) of their mass is converted to energy. The value of ε is in part determined by the strength of the strong nuclear force. If ε were 0.006, a proton could not bond to a neutron, and only hydrogen could exist, and complex chemistry would be impossible. According to Rees, if it were above 0.008, no hydrogen would exist, as all the hydrogen would have been fused shortly after the Big Bang.
Omega (Ω), commonly known as the density parameter, is the relative importance of gravity and expansion energy in the universe. It is the ratio of the mass density of the universe to the “critical density” and is approximately 1. If gravity were too strong compared with dark energy and the initial cosmic expansion rate, the universe would have collapsed before life could have evolved. If gravity were too weak, no stars would have formed.
Lambda (Λ), commonly known as the cosmological constant, describes the ratio of the density of dark energy to the critical energy density of the universe, given certain reasonable assumptions such as that dark energy density is a constant. In terms of Planck units, and as a natural dimensionless value, Λ is on the order of 10-¹²² (medium’s formatting screws up writing negative powers). This is so small that it has no significant effect on cosmic structures that are smaller than a billion light-years across. A slightly larger value of the cosmological constant would have caused space to expand rapidly enough that stars and other astronomical structures would not be able to form.
Q, the ratio of the gravitational energy required to pull a large galaxy apart to the energy equivalent of its mass, is around 10-⁵. If it is too small, no stars can form. If it is too large, no stars can survive because the universe is too violent.
The level of fine-tuning we see in the laws of physics is often given as evidence for some form of multiverse theory, whereby there must be multiple universes with different laws, and most won’t have life, but by randomly stumbling on the right set of laws of physics, some will.
The argument against this fine-tuning being evidence for cosmological natural selection is the anthropic principle or the observation selection effect, which points out that you can only think ‘huh, that’s weird, all those laws are just right’ if you’re around to think in the first place. If the universe didn’t have all those laws just right, there’d be no one to think ‘oh, that’s a shame’.
However, the anthropic principle does not explain why we don’t live in a universe with only some opportunities for life, and not the incredible vastness of opportunities for life that we see in our universe. The universe is estimated to contain one septillion stars — that’s a one followed by 24 zeros. We once thought planets might be quite rare, but we now estimate there’s probably at least one planet per star, and that one in five sun-like stars has an Earth-sized planet in the habitable zone. We also now know that liquid water oceans frequently exist beneath the surface of icy moons. There are six icy moons in the solar system with liquid water oceans, which could theoretically support life thanks to volcanism driven by gravitational friction. If that number is representative of the number of icy moons orbiting gas giants in other solar systems, that means septillions of worlds in the universe potentially able to support life.
If there were merely thousands or millions of worlds in the universe potentially able to support life, then perhaps we could write off how well-tuned the universe appears to support life as an artefact of the anthropic principle. But the anthropic principle can’t really explain why the universe creates so many billions upon billions upon billions of chances for life.
It’s very hard to get your head around quite how big a number a septillion is. Written out, it’s 1,000,000,000,000,000,000,000,000. Potential habitable worlds could be a trillion times less likely to form in the universe, and there would still be a trillion habitable worlds left for thinking beings to evolve on and invent the concept of an anthropic principle. Therefore, I think the anthropic principle does not adequately explain away the extent to which the universe is optimised for complexity and, ultimately, for life.
The universe starts forming complex structures faster than anticipated
If the universe did not evolve to produce complexity and life, then things are just bumping into each other at random and just happen to form ever more complex structures over time. That process takes a while, so you might expect complex structures to only appear later in the history of the universe, not not relatively near the start.
However, scientists’ model of how the universe gradually develops complexity (goes from a load of gas to stars, and planets and galaxies etc.) keeps getting shown to be wrong in the same direction — that direction being ever more complexity is found ever earlier on in the universe the more we’re able to look.
Here’s Julian (Egg and the Rock) summarising the prevailing model of how galaxies formed (prior to James Webb’s recent finding) :
The old assumption was that highly structured spiral galaxies came about slowly and late, through bottom-up structure formation. Bottom-up structure formation essentially means order arising very, very slowly from a lot of randomness, as early solitary stars clump (under the influence of gravity) to form star clusters, which clump to form dwarf galaxies, which merge to form small, irregularly-shaped galaxies, which merge to form larger also peculiarly-shaped galaxies, some of which eventually settle down and find a spiral structure. But the assumption was that you simply couldn’t get large numbers of spiral galaxies in the first few billion years of the universe’s existence, as, even if they had somehow managed to form, they would be disrupted by all that clumping and merging.
The James Webb space telescope can peer further back into the history of the early universe than we ever could before. It’s found star formation earlier than had been predicted, as early as 100 million years after the Big Bang. Star formation is important for cosmological natural selection, because large stars collapse to form black holes. Universes that evolve to produce lots of star formation produce more black holes.
It also found galaxy formation far earlier than predicted. A new paper published in January 2025 shows that super-massive black holes form far earlier than predicted, within the first 100 million years after the Big Bang.
All these previous errors in cosmology are all wrong in the same direction — they’re all predicting complex structures taking longer to develop than we later find out to be the case. Meanwhile Julian, who isn’t a scientist by background, keeps making predictions about what James Webb will uncover that later are shown to be correct, like early galaxy formation and the early formation of ‘direct collapse’ black holes. He’s making these predictions on the basis of his model of the universe having evolved to optimise for black hole formation, and what the model predicts keeps turning out to be the case.
In his model, the first black holes are supermassive black holes that form very early through the direct collapse of the uniform gas in the early universe. These supermassive black holes spur star formation by stirring up the gas of the early universe. Stars eventually collapse to form smaller black holes, thus creating far more black holes from a given amount of matter than direct collapse supermassive black holes. Then life evolves on planets, and this leads to intelligence and technological civilisations, which create artificial black holes, which are far smaller than stellar-mass black holes.
The sweet spot for the mass of an artificial black hole is about the mass of Mount Everest because a black hole of that size throws off a huge amount of power without evaporating too quickly to be useful. With the mass of a star big enough to form a black hole (3.978¹⁰³⁰kg) you could create almost five trillion (4,911,111,100,000,000) Everest mass black holes. Far more efficient! But these black holes can’t form naturally, they need intelligent beings to make them. Therefore, universes that happen to be able to support intelligent life (the more, the better) have more offspring (via artificial black holes).
Why would advanced civilizations build black holes? Because the laws of physics are such that they are by far the best way to produce energy. Nuclear fission can only convert roughly 0.1% of its fuel into energy, while nuclear fusion, at its most efficient, converts roughly 0.7%. Black holes can convert 42% of any mass thrown into them into energy. The laws of physics make black holes so useful that any sufficiently advanced technological civilisation would be bound to develop them.
Life starts very early in the history of the universe
The universe is 13.7 billion years old. Sounds quite old, but we exist very early in its potential lifespan. Star formation will cease in around 100 trillion years, after which point the universe will be mostly dark, with drastically fewer opportunities for life to emerge. Life didn’t emerge yesterday; it’s over 3.5 billion years old. Possibly as old as 4.4 billion years old, meaning life on Earth emerged after just 9–10 billion years. Life elsewhere in the universe could have emerged even earlier, although we have no way of knowing as of yet.
Our universe’s current age is only 0.013% of the way through the era of its existence when complex life is likely to be possible. That’s very early.
If the universe’s life from birth to the end of the stellar era (when star formation stops) was scaled down to 100 years, then we’d be on day three. Still practically a newborn!
If you used a random number generator to generate numbers between 1 and 100, most of the numbers generated would not be near either end. 80% would be over 10 and under 90, and 98% would be over 1 and under 100. Yet here we are, not even on one, but on 0.013, right slap bang at the start. That needs some explanation. Why does the universe generate conditions suitable for life to emerge so quickly?
One potential answer is that it evolved to do so. If black holes create universes, then most universes are in branches of the universe family tree that are more likely to produce lots of black hole ‘offspring’. The most mass-efficient way to produce black holes is via the application of intelligence, so universes might evolve to be able to support life.
My additional thought
Now for some idle speculation for me. So we know black holes are singularities, and we think they might create big bangs with nested universes. What else do we know about black holes? We know that they evaporate.
What would it be like to be in a universe inside a black hole that was evaporating? Well, I don’t know. But as the black hole starts to rapidly get smaller and therefore evaporate faster, it might look something like this:
All the matter of the universe, from stars and galaxies to atoms and subatomic particles, and even spacetime itself, is progressively torn apart by the expansion of the universe at a certain time in the future, until distances between particles will infinitely increase.
That’s the summary of the ‘Big Rip’, which is lifted directly from Wikipedia and is one of the potential ways the universe will end. If the universe exists inside a black hole, and said black hole is evaporating, it would get smaller over time, and therefore, the rate of evaporation would increase. In the final stages, when it’s gotten very small, the rate of evaporation would increase rapidly and you’d get the ‘big rip’ as it evaporates entirely.
Now to quote Katie Mack, a theoretical cosmologist at the Perimeter Institute for Theoretical Physics in Waterloo, Canada:
“So the Big Rip is an idea that comes back to this question of dark energy. We don’t know what it is that’s making the universe expand faster. We call it “dark” energy because we don’t know what it is. But there’s something that’s accelerating the expansion of the universe. Now, if it’s just a cosmological constant, if it’s just a property of the cosmos, then we know how that goes. You know, it leads us to heat death, where all the galaxies are maximally isolated, and then they fade away.
There are other hypothetical possibilities for dark energy. There are some where instead of being just a constant background in the cosmos, it’s something that is dynamical. It’s something that could change over time. And specifically, you can write down equations for something where it gets more powerful over time. Where whatever this is that’s the kind of stretchiness built into the cosmos, it’s a dynamical field, an energy field, and it gets more powerful over time. And so that it starts stretching the universe faster and faster. Not just causing acceleration but building up within objects.”
Now a quote from Adam Brown, theoretical physicist at Stanford:
“There was then a learned debate for many years about, you know, the universe is expanding, but is it expanding sufficiently slowly that it’ll then recollapse in a big crunch, like a time reverse of the Big Bang, and that’ll be super bad for us? Or is it going to keep expanding forever, but just sort of ever more slowly as gravity pulls it back, but it’s fast enough that it keeps expanding?
And there was a big debate around this question, and it turns out the answer to that question is neither. Neither of them is correct. In possibly the worst day in human history, sometime in the 1990s, we discovered that in fact, not only is the universe expanding, it’s expanding faster and faster and faster.
It’s what we call dark energy, or the cosmological constant. This is just a word for uncertainty. What is making the universe expand at an ever faster rate, accelerated expansion as the universe grows?”
The rate at which the universe is expanding is speeding up exponentially from a very low base. Remeber, the cosmological constant is tiny — that’s one of the values that appear to be fine tuned to life.
Recap: Λ (the cosmological constant) is on the order of 10-¹²² This is so small that it has no significant effect on cosmic structures that are smaller than a billion light-years across. A slightly larger value of the cosmological constant would have caused space to expand rapidly enough that stars and other astronomical structures would not be able to form.
Black holes evaporate exponentially (actually technically super-exponentially). Big black holes evaporate very slowly, small black holes evaporate very quickly. If the universe was inside a black hole, it would evaporate very slowly for a very long time, with the rate of evaporation speeding up as it shrank. So if the universe were inside a black hole you’d expect the cosmological constant to be very small for most of its lifespan, which it is, and growing over time, which it is.
So maybe– just maybe– the mysterious force making the universe expand faster (that we call dark energy because we don’t know what it is) is related to the universe we’re in being inside a black hole that’s evaporating? I’m not a physicist, so I’ve no idea how you could go about probing that question, but hey, it’s an interesting question to ask.
Lots of things about this idea don’t exactly add up, but I thought it’s interesting to throw out there for further thought, in case it prompts other related ideas.