Towards a Kardashev Type II civilisation

When considering civilisation as an astronomical phenomenon the most convenient formulation to use relates to energy consumption. Energy is the bottom line for all activities and processes, and the ultimate observable on which to base physical insights.

(I would elaborate that the most conducive way to consider energy is in fact in terms of Information Theory, but that is the subject of a different occasional series of blog posts relating to the question "how real is real?". This series is concerned not with the universe in general, but with our place in it. Perhaps the two series will converge at some point since the Anthropic Principle is inevitably invoked in relation to both).

I have written previously in "Towards a Kardashev Type I civilisation" about how our civilisation's energy consumption is propelling it towards a crisis that will transform it. In particular, we will have to adopt a "circular" approach to economics in which non-renewable resources are indefinitely circulated through cycles of economic activity using renewable energy.

This has profound consequences for our concepts of value and the accumulation of wealth which will alter the whole basis on which our economies are conceived and function. We see this crisis manifested in terms of climate change, its impacts and our responses. This transformation is associated with our civilisation achieving Kardashev Type I status.

The Kardashev Scale describes the energy consumption of a civilisation in astronomical terms. Type I corresponds roughly to the consumption of all the energy available on a planet like the Earth; Type II civilisations consume all the energy from a star; Type III civilisations use galactic quantities of energy. A Google search on "Kardashev" quickly yields many hits providing detailed elaboration of these ideas.

The key things I want to talk about here are what is involved in progressing from Type I to Type II status and what is the possible signature that specifically a Type II civilisation might have, in astronomical terms, that would enable its detection by us.

Kardashev himself, a Soviet astronomer who worked on the search for extraterrestrial intelligence in the sixties, stopped at Type III, but the scale has been modified and extended by others since, and there has been speculation about what Types IV and above might imply, with the possibility being raised that Type V or VI civilisations may be able to manipulate and define the laws of physics themselves.

In general, a formulation based on a logarithm of energy consumption provides a useful way of relating the scale to physical observables, in the same way that the qualitative impressions about the brightness of a star can be expressed quantitatively in terms of stellar magnitude. According to this, Humanity currently has a score somewhere between 0.7 and 0.8, and some commentators speculate that it will achieve Type I status within a few centuries.

One thing that interests me about the Kardashev scale is the way it articulates the idea of intelligence (extraterrestrial or otherwise) as a physical process with quantifiable, measurable consequences; the idea of intelligence as an astronomical observable. Ultimately, it is my belief (or hunch) that valid descriptions of the universe, that is, physics, are intimately connected to the way information is processed.

I have begun to describe my intuitions about this in a previous article "how real is real (part 1)?" in relation to the way the universe is described. I will continue this in a future post (working title "how real is real (part 2)?").

There is an encoding of information that can only be implemented on an intrinsically distributed system, that is, one that can and must be embedded in and be part of the universe it is used to describe, and which cannot be simulated to an arbitrary degree of precision using only sequential processes. Structures are encoded such that correlational features of data at one level of nesting are distributional features at another. This means all observable phenomena can be encoded.

The encoding is consistent with the description of entropy in the previous article. It is tempting to speculate that the nature of these phenomena is a consequence of the way they can be encoded if one constrains the mechanism for the encoding to be embedded in or implemented using the thing that is encoded in a lossless and minimal manner. The Universe is the way it is, as we understand it, because there is no other way it could be without invoking some higher reality which then requires further explanation. Time is implicitly encoded: there is no system clock provided by some external deity to run a sequential process that simulates the way time is manifested.  

This really constitutes a statement of the Anthropic Principle: the universe is more than just intelligible. It is intelligibility itself. Whatever we understand about the universe is part of the universe. The encoding is intelligence. Perceptions are not recordings made by some sensory apparatus as though our brains were probes for some disembodied intelligence, some ghostly homunculus or avatar.  

(To be clear, this is not an atheist statement. Rather, it is nothing more that the observation that divinity will not be limited or constrained by the laziness with which we imagine or represent it)  

So if we are seeking extraterrestrial intelligence, we have already found it: all intelligence is extraterrestrial, in that it is a fundamental property of the universe. Our intelligence is extraterrestrial in the same way our substance is: it originated among the stars and was present at their formation. The progress of intelligence through the different stages of development described by the Kardashev Scale is a kind of homecoming. All our music is ultimately the song of an exile seeking to return to the vast silent ego-less monotony of space. This is the nostos of the human epic. With childlike fingers we trace the outline of gods among the constellated stars because of the intuition of what we must become.    

So what are the practical realities of our first stumbling childish steps?

I have written in my recent review of 2015, "14 hours and counting" of a developments which may not have attracted as much media attention as their significance warrants. One key development which I believe is more significant even than the Moon Landings of the Apollo Space Programme is the development of truly re-usable space vehicles. In 2015 various companies successfully landed the primary stage of their rocket systems after launch, making it available for re-use. This means space flight can now be an activity that satisfies the requirements of the circular economy of a Kardashev Type I civilisation. Progress towards Type II status would not be possible otherwise.  

In the same article I speculated about a number that characterises any space-faring Type I civilisation, which I called "intrinsic countdown" (a clumsy term: I would be delighted for someone to propose an alternative). This is the "integration" time required for a renewable energy system to accumulate the energy necessary to propel material into orbit, expressed in terms of one kilogram of material per square metre of the planet's surface. This number represents a physical limit that constrains a Type I civilisation and which must be overcome to progress to Type II status. Space flight which is undertaken on the basis of circular economics must observe this constraint in a Type I civilisation. Type II status requires space flight that is not thus constrained.

(N.B. the figure of 14 hours in the article was the result of a calculation so rough it did not require all of the back of the envelope on which it was made. Please feel free to do the calculation properly!)
 
There is a range of possible values for this time. On the one hand the orbit of a planet on which a Type I civilisation develops must be within the "habitable zone". This limits the renewable energy resource per square metre available to be accumulated and indicates a lower limit on the time. The planet must also be massive enough to retain an atmosphere capable of supporting a suitably diverse biosphere. This also means there is a lower limit. An upper limit arises from stellar evolution and the window of opportunity this present to any developing civilisation.

Progress towards Type II status requires us to overcome the constraint imposed by this minimum countdown to lift-off. It requires a process of modification of our civilisation through technological innovation so that we can extend the zone that is "habitable" for it beyond biological constraints to include regions within the orbit of Mercury, where the energy resource per square metre is much more abundant. It is a physical process, mediated by intelligence, that relates renewable energy available from the Sun, and subject to geometric attenuation with distance from the Sun, to the gravitational potential energy of objects here on Earth. It is the process by which the physical observable, intelligence, diffuses and becomes manifested over a region of space associated with a star rather than a planet. Perhaps the term above should be "intelligence diffusion constant" or something like that?  

If there is a Kardashev Type II civilisation somewhere already, what does it look like to us?

The search for extraterrestrial intelligence has focussed on two kinds of emission from distant star systems. We might be receiving a signal that has been deliberately contrived to communicate an intelligent origin. Alternatively, we might be able to detect "light pollution", that is,  inadvertent emissions corresponding to waste heat from industrial processes with a particular signature in terms of emission lines. So far these approaches have not met with success. However, there is another characteristic we should consider.

A Type II civilisation that has developed along the lines I describe above will correspond to a system in which the energy from its star is transmitted throughout a larger volume to enable the various activities and processes of this civilisation. Therefore, as this energy is used and inevitably lost as waste heat, the volume from which the radiation we observe is emitted will be larger than the volume of the star. We will observe the same luminosity, but it will originate from an object with a larger apparent size than the star to which it corresponds. To be clear, all the energy from the star must be radiated at some point, and the presence of intelligence, in the form of a Kardashev Type II civilisation, means the volume of the object radiating it will be larger than the star.

Again we see intelligence as a physical phenomenon, in this instance one that causes a change in the spectrum of a star. If the energy from the star is radiated after it is used, as it must, then the star will appear to be shifted from the main sequence on a Hertzsprung-Russell diagram. It has the same luminosity, but a different apparent temperature. We should look for Kardashev Type II civilisations among outliers on the main sequence.

There is a scenario where this will not be the case. One can imagine that the transmission of energy between locations within the volume of space occupied by the Type II civilisation could be achieved using narrow energy beams that are not subject to geometric attenuation. Indeed, this may be the only way that it is possible for the civilisation to occupy a volume larger than the narrow orbit dictated by its initial progress from Type I to Type II as described above.

It is possible that, as it moves towards Type III status, interstellar travel is made possible using these narrow energy beams. It may be the case that all of the energy from the star becomes directed along these narrow corridors. Perhaps once Type III status is achieved the galaxy becomes criss-crossed by an intersecting network of energy corridors between stars that are otherwise completely dark. Perhaps we are already surrounded by a Type III civilisation without knowing it. We would only be able to observe a star involved in this civilisation if the Earth happened to cross one of the energy corridors, and it is entirely possible that the chances against this happening may be literally astronomical.

Perhaps intelligence is dark matter, and the stars that we can observe are those that still share our savagery, left there for us to superimpose our childish pictures on by a galactic Type III society. Perhaps the observable universe can only ever be a nursery by definition.