Illustration by Tianhua Mao
Perhaps Arthur C. Clarke was being uncharacteristically unambitious. He once pointed out that any sufficiently advanced technology is going to be indistinguishable from magic. If you dropped in on a bunch of Paleolithic farmers with your iPhone and a pair of sneakers, you’d undoubtedly seem pretty magical. But the contrast is only middling: The farmers would still recognize you as basically like them, and before long they’d be taking selfies. But what if life has moved so far on that it doesn’t just appear magical, but appears like physics?
After all, if the cosmos holds other life, and if some of that life has evolved beyond our own waypoints of complexity and technology, we should be considering some very extreme possibilities. Today’s futurists and believers in a machine “singularity” predict that life and its technological baggage might end up so beyond our ken that we wouldn’t even realize we were staring at it. That’s quite a claim, yet it would neatly explain why we have yet to see advanced intelligence in the cosmos around us, despite the sheer number of planets it could have arisen on—the so-called Fermi Paradox.
For example, if machines continue to grow exponentially in speed and sophistication, they will one day be able to decode the staggering complexity of the living world, from its atoms and molecules all the way up to entire planetary biomes. Presumably life doesn’t have to be made of atoms and molecules, but could be assembled from any set of building blocks with the requisite complexity. If so, a civilization could then transcribe itself and its entire physical realm into new forms. Indeed, perhaps our universe is one of the new forms into which some other civilization transcribed its world.
These possibilities might seem wholly untestable, because part of the conceit is that sufficiently advanced life will not just be unrecognizable as such, but will blend completely into the fabric of what we’ve thought of as nature. But viewed through the warped bottom of a beer glass, we can pick out a few cosmic phenomena that—at crazy as it sounds—might fit the requirements.
For example, only about 5 percent of the mass-energy of the universe consists of ordinary matter: the protons, neutrons, and electrons that we’re composed of. A much larger 27 percent is thought to be unseen, still mysterious stuff. Astronomical evidence for this dark, gravitating matter is convincing, albeit still not without question. Vast halos of dark matter seem to lurk around galaxies, providing mass that helps hold things together via gravity. On even larger scales, the web-like topography traced by luminous gas and stars also hints at unseen mass.
Cosmologists usually assume that dark matter has no microstructure. They think it consists of subatomic particles that interact only via gravity and the weak nuclear force and therefore slump into tenuous, featureless swathes. They have arguments to support this point of view, but of course we don’t really know for sure. Some astronomers, noting subtle mismatches between observations and models, have suggested that dark matter has a richer inner life. At least some component may comprise particles that interact with one another via long-range forces. It may seem dark to us, but have its own version of light that our eyes cannot see.
In that case, dark matter could contain real complexity, and perhaps it is where all technologically advanced life ends up or where most life has always been. What better way to escape the nasty vagaries of supernova and gamma-ray bursts than to adopt a form that is immune to electromagnetic radiation? Upload your world to the huge amount of real estate on the dark side and be done with it.
If you’re a civilization that has learned how to encode living systems in different substrates, all you need to do is build a normal-matter-to-dark-matter data-transfer system: a dark-matter 3D printer. Perhaps the mismatch of astronomical models and observations is evidence not just of self-interacting dark matter, but of dark matter that is being artificially manipulated.
Or to take this a step further, perhaps the behavior of normal cosmic matter that we attribute to dark matter is brought on by something else altogether: a living state that manipulates luminous matter for its own purposes. Consider that at present we have neither identified the dark-matter particles nor come up with a compelling alternative to our laws of physics that would account for the behavior of galaxies and clusters of galaxies. Would an explanation in terms of life be any less plausible than a failure of established laws?
Part of the fabric of the universe is a product of intelligence.
The universe does other funky and unexpected stuff. Notably, it began to expand at an accelerated rate about 5 billion years ago. This acceleration is conventionally chalked up to dark energy. But cosmologists don’t know why the cosmic acceleration began when it did. In fact, one explanation with a modicum of traction is that the timing has to do with life—an anthropic argument. The dark energy didn’t become significant until enough time had gone by for life to take hold on Earth. For many cosmologists, that means our universe must be part of a vast multiverse where the strength of dark energy varies from place to place. We live in one of the places suitable for life like us. Elsewhere, dark energy is stronger and blows the universe apart too quickly for cosmic structures to form and life to take root.
But perhaps there is another reason for the timing coincidence: that dark energy is related to the activities of living things. After all, any very early life in the universe would have already experienced 8 billion years of evolutionary time by the time expansion began to accelerate. It’s a stretch, but maybe there’s something about life itself that affects the cosmos, or maybe those well-evolved denizens decided to tinker with the expansion.
There are even possible motivations for that action. Life absorbs low-entropy energy (such as visible light from the sun), does useful work with that energy, and dumps higher-entropy energy back into the universe as waste heat. But if the surrounding universe ever got too warm—too filled with thermal refuse—things would stagnate. Luckily we live in an expanding and constantly cooling cosmos. What better long-term investment by some hypothetical life 5 billion years ago than to get the universe to cool even faster? To be sure, it may come to rue its decision: Hundreds of billions of years later the accelerating expansion would dilute matter so quickly that civilizations would run out of fresh sources of energy. Also, an accelerating universe does not cool forever, but eventually approaches a floor in temperature.
One idea for the mechanism of an accelerating cosmic expansion is called quintessence, a relative of the Higgs field that permeates the cosmos. Perhaps some clever life 5 billion years ago figured out how to activate that field. How? Beats me, but it’s a thought-provoking idea, and it echoes some of the thinking of cosmologist Freeman Dyson’s famous 1979 paper “Time Without End,” where he looked at life’s ability in the far, far future to act on an astrophysical scale.
Once we start proposing that life could be part of the solution to cosmic mysteries, there’s no end to the fun possibilities. Although dark-matter life is a pretty exotic idea, it’s still conceivable that we might recognize what it is, even capturing it in our labs one day (or being captured by it). We can take a tumble down a different rabbit hole by considering that we don’t recognize advanced life because it forms an integral and unsuspicious part of what we’ve considered to be the natural world.
Life’s desire to avoid trouble points to some options. If it has a choice, life always looks for ways to lower its existential risk. You don’t build your nest on the weakest branch or produce trillions of single-celled clones unless you build in some variation and backup.
Maybe there’s something about life itself that affects the cosmos.
A species can mitigate risk by spreading, decentralizing, and seeding as much real estate as possible. In this context, hyper-advanced life is going to look for ways to get rid of physical locality and to maximize redundancy and flexibility. The quantum realm offers good options. The cosmos is already packed with electromagnetic energy. Today, at any instant, about 400 photons of cosmic microwave radiation are streaming through any cubic centimeter of free space. They collectively have less energy than ordinary particles such as protons and electrons, but vastly outnumber them. That’s a lot of potential data carriers. Furthermore, we could imagine that these photons are cleverly quantum-mechanically entangled to help with error control.
By storing its essential data in photons, life could give itself a distributed backup system. And it could go further, manipulating new photons emitted by stars to dictate how they interact with matter. Fronts of electromagnetic radiation could be reaching across the cosmos to set in motion chains of interstellar or planetary chemistry with exquisite timing, exploiting wave interference and excitation energies in atoms and molecules. The science-fiction writer Stanisław Lem put forward a similar idea, involving neutrinos rather than photons, in the novel His Master’s Voice.
That’s one way that life could disappear into ordinary physics. But even these ideas skirt the most disquieting extrapolations.
Toward the end of Carl Sagan’s 1985 science-fiction novel Contact, the protagonist follows the suggestion of an extraterrestrial to study transcendental numbers. After computing to 1020 places, she finds a clearly artificial message embedded in the digits of this fundamental number. In other words, part of the fabric of the universe is a product of intelligence or is perhaps even life itself.
It’s a great mind-bending twist for a book. Perhaps hyper-advanced life isn’t just external. Perhaps it’s already all around. It is embedded in what we perceive to be physics itself, from the root behavior of particles and fields to the phenomena of complexity and emergence.
In other words, life might not just be in the equations. It might be the equations.
Caleb Scharf is an astrophysicist, the Director of Astrobiology at Columbia University in New York, and a founder of yhousenyc.org, an institute that studies human and machine consciousness. His latest book is The Copernicus Complex: Our Cosmic Significance in a Universe of Planets and Probabilities.