One of the most burning questions we are faced with when we marvel at the grandness of the universe and the diversity of life on Earth, is: Why the hell can’t we find any aliens?
I’m not talking about bacteria or frozen spores on some asteroid or moon, but intelligent species — interstellar civilizations we can recognize and communicate with. After all, according to the Kardashev scale and given the age of the universe, there should be at least a type II civilization in our own galaxy, and possibly several (or many!) type IIIs throughout the universe. And we ought to be able to observe them with the technology we currently have, as the radiation output of their massive energy conversion would be measurable.
But we’ve found nothing. Nada. Zilch.
Why are they so hard to find? Are we actually alone out here? Or are we, maybe, the first ones to speak up into the void? Or the last? *shudders*
“Why is the galaxy not crawling with self designing mechanical or biological life forms? Why hasn’t the Earth been visited, and even colonised?” ~Stephen Hawking
Maybe the problem lies elsewhere. Maybe we’re expecting the wrong results.
As you probably imagine (or know), many brilliant scientists and inquisitive minds have bent over backwards trying to answer these questions, giving birth to some of the most exciting solutions to the Fermi paradox (high probability of alien life in the universe, apparently no traces of it).
Let’s draw a broad sketch of the issue.
Nicolai Kardashev postulated that as an intelligent species evolves, it will eventually be able to harness and use the entire energy output of its home planet (type I) > then its home star system (by building a Dyson sphere around the star, for example)(type II) > then its home galaxy (type III).
This requires that such a species evolves in an expansionist manner, colonizing its entire galaxy and consuming its entire energy output.
Evidently, such a tremendous evolutionary step requires a phenomenal use of technology on a mind-boggling scale. Enveloping an entire galaxy in an artificial construction, or every single star within it, and using that energy to sustain an enormous, expansionist civilization, will inevitably be detectable. Even if our observational technology is measly by comparison, we’d still be able to detect something by the sheer immensity of its effect on the surrounding universe. By its shadow, so to speak. Or its gargantuan footsteps.
But we’ve found no such civilization out there.
SETI’s G-HAT survey (in which they studied over 100.000 galaxies looking for traces of a type III civilization) has returned a pretty grim result, namely zero. No such thing as a Kardashev type III civilization out there. A real bummer.
Of course, this result says nothing about type Is, for example, which would be far harder to detect. But it still begs a very important question: Was Kardashev wrong?
Why can’t we find any advanced alien civilizations out there?
Let’s go down the rabbit hole and look for possible answers.
Keith Cooper, a freelance science journalist, recently speculated on this topic over at Centaury Dreams. He proposed three possible explanations why civilizations might fall of the Kardashev scale at some point, seemingly never reaching a type III level.
1. They fail to colonize the stars
A strong argument in favor of this explanation is Geoffrey Landis’ percolation theory.
Landis assumes that interstellar travel is short distance only, as travel to far destinations would require hundreds of years and thus be unfeasible. So an interstellar civilizations will expand gradually, in bursts, colonizing the neighboring systems one by one.
Not all of these systems will be colonizable (or warrant the effort), and thus some will become dead ends. Similarly, some systems will be so far away from their next neighbors, they too will become dead ends. Thus, an expanding interstellar civilization will grow outward like the roots (or branches) of a tree, until all its ramifications will meet dead ends and expansion will stop. No type III.
2. Their energy requirements are low
Another theory is that civilizations, as they evolve and become more efficient, will have lower energy demands, not higher. Such civilizations are driven by optimization and specialization, not expansion and comsumption. An optimized society will also not increase in numbers significantly, and thus not need to colonize new worlds to sustain its growth.
Such a civilization will very likely travel to other systems, but to explore and gain knowledge, not to seize and consume. They might very well be galactic, and even inter-galactic, but they wouldn’t occupy a place on the Kardashev scale.
3. Black holes are more interesting
This is the most beautiful puppy theory of all.
If we assume that an evolving civilization will become more efficient and also require more energy, what’s the likeliest target of their interest? Black holes. Infinite energy, condensed into the tiniest possible space. There’s a good reason why all scientists get giddy when one mentions black holes: they’re fascinating and terrifying at the same time (er, the black holes, not the scientists).
Several people have developed theories around the possibility of harnessing energy from black holes, and the results are mind-blowing.
“Paul Davies in his book The Eerie Silence suggests that a spinning black hole could power our present human levels of energy consumption for at least a trillion trillion years, long after the stars have gone out.” ~Keith Cooper, SETI: The Black Hole Alternative
So it makes perfect sense that a sufficiently evolved civilization won’t seek to spend energy painstakingly colonizing an entire galaxy, only to harness the output of volatile stars, if it can focus on harnessing the power of black holes.
They could build Dyson sphere variants around black holes; tap into the blasting energy output of their accretion disks or jets; or use the rotational energy of spinning black holes. There’s also a surprising number of x-ray binaries (black hole plus star) even in our own galaxy, inviting the speculative notion that evolved civilizations create their own black holes in their (or the neighboring) systems to use as an energy source.
But the fascination with black holes as an alternative focus to expansion goes well beyond their energy potential. Black holes could make the most powerful computers imaginable. They could also be gateways to other universes or existential dimmensions, where super-advanced civilizations go to be among their peers, leaving us barbaric beasts behind to crawl across normal space-time at our glacial tempo.
The Transcension Hypothesis speculates on exactly this alternative: that sufficiently advanced civilizations may invariably leave our universe.
The evolution of life on Earth points toward specialization and ever decreasing scales of manipulative dexterity. Extrapolating that to alien civilizations, we’d invariably conclude that they’d much more likely develop toward the micro-, nano-, and subatomic scale, and head inward, into the infinite density and energy of black holes, as opposed to dedicating themselves to greater and larger constructions, hugely growing energy demands and unsustainable scales.
“Evolutionary development guides intelligent life increasingly into inner space and what is referred to as STEM, small scales of space, time, energy and matter.” ~Owen Nicholas, The Transcension Hypothesis
There are some compelling reasons why black holes are attractive to civilizations focused on achieving great STEM density. Miniaturizing civilizations, who re-engineer themselves with femtotechnology (structures at sub-atomic scales) will undoubtedly be intrigued by the challenge of entering and harvesting a black hole without losing structural integrity. All the while, the proximity to black holes essentially fast-forwards them through time, as the rest of the galaxy and universe would speed through its processes in the blink of a subjective eye.
Also, such civilizations—due to their crossing of the computational threshold between noisy, inefficient technologies, and highly specialized, efficient ones—would undoubtedly exist in a sort of “radio silence,” as they would have near zero untargeted, unintentional emissions. So we’d be unable to spot them by their noise.
Just imagine. If you’re a civilization that has created a super dense, super efficient and super fast computational capacity (called ‘computronium’) by relocating to and using black holes, you may increasingly find the rest of the universe slow and boring by comparison. And you’d not be interested in communicating with it or listening to its primitive noise, as such investment on your part would yield no new benefits.
Black holes would be the ultimate tool to exponentially increase your knowledge and power, to essentially blow up the evolutionary scale. Certain classes of accretion discs around super-massive black holes are such monstrously efficient energy harvesters (in some cases 50 times more efficient than stellar nuclear fusion), it begs for speculations about such formations bearing proof that advanced civilizations are at work, rather than coincidental natural phenomena.
And to color our little speculative neuronal explosions even more, such civilizations will invariably evolve non-biological intelligences, which in turn will escape natural evolution and transcend ‘life’ via intentional development. The phenomenal computational capacities facilitated by the manipulation of black holes will invariably yield non-biological organisms that far out-perform and surpas biological life-forms in their development and use of natural resources (such as black holes).
Essentially, we might just as well assume that any civilization that evolves to use black holes will transcend the biological, and
“The hallmark of developmental processes is convergence and unification. A planet of postbiological life forms, if subject to universal development, may increasingly look like one integrated organism, and if so, its entities will be vastly more responsible, regulated, and self-restrained than human beings. If developmental immunity exists, planetary transitions from life to intelligent life, and from intelligent life to postbiological life should be increasingly high-probability.” ~Gregory Stock (biophysicist), The Transcension Hypothesis
It all makes for awesome speculative ideas, doesn’t it?
So to end on a high note, still tasting of wonderful speculation and multi-faceted story material:
The lack of proof of expansionist, consumeristic alien civilizations doesn’t mean we’re alone in the universe. It may just as well mean we have some evolutionary — no, developmental — stages to look forward to that will see us transcend all we currently know to be ‘life,’ and enter a realm of supreme efficiency, computational capacity, and self-realizing potential.
How’s that for science-fiction story material.