Where are They? - The Kardashev Scale explained.

Excerpt from Chapter 3. 

​Chapter 3
The Kardashev Scale
 
 
Chapter 2 had some things to say about “civilisations” and “advanced civilisations”. But what are those things? What do we mean by “an advanced civilisation”? The Kardashev Scale is there to answer that question.
 
Nikolai Kardashev is a Russian astrophysicist (he is still alive in 2017 at the age of 85). Born in Moscow in 1932, he graduated from Moscow State University at the age of twenty-two and began postgraduate studies in the University’s Sternberg Astronomical Institute, completing his PhD in Physical and Mathematical Sciences in 1962.
 
In 1963, Kardashev took part in the first Russian search for extraterrestrial intelligence. While examining quasar CTA-102, he developed his ideas about what form extraterrestrial civilisations might take. They could, he realised, be ahead of anything on Earth by millions, and perhaps billions, of years. He developed the Kardashev Scale to define levels of possible civilisation. The original Kardashev scale had three levels (later researchers have added more).
 
The most important thing to understand about the Kardashev Scale is that it is based on energy. As Kardashev sees it, the level a civilisation has reached can be measured by the amount of energy it consumes.
 
In addition to energy, Kardashev focused on communications technology. (Those later researchers have also included other factors). In his paper, Transmission of Information by Extraterrestrial Civilisation, Kardashev said that an advanced civilisation would be able to transmit radio signals over great distances in space. The levels of civilisation he defined were:

• Type 0 civilisations. This is not, in fact, one of Kardashev’s original three; it’s added here because this is where Earth is at present.
• Type I civilisations, or planetary civilisations, are able to use all of the energy available on their own planet. This includes all energy the planet is capable of producing, and all energy (such as solar energy) reaching it from space. This is the level Earth has currently almost reached, though the present view is that a genuine Type I civilisation should also have developed the ability to control things like volcanoes, weather, and earthquakes and would also be likely to be building cities in the oceans. Clearly, then, Earth has not yet quite reached the level of a Type 1 civilisation; Carl Sagan put Earth’s current level of development at seventy percent of Type I, so that Earth is, in reality, a Type 0 civilisation.
• Type 2 civilisations have reached the level at which they can make use of all of their star’s energy, and not just the solar energy that reaches their planet from the star. Stars, of course, transmit energy in every direction and planets orbiting them receive only a small fraction of the total. How, instead, a planet might collect all of the energy emitted is an interesting challenge. In 1960, Freeman Dyson put forward the idea of the Dyson Sphere, a structure that would enclose a star completely, capture all of the energy it emits, and transfer it to the home planet. There’s an interesting sidelight here: what would happen if two planets orbiting one star both had advanced civilisations, and one of them constructed a Dyson Sphere? That would dwarf the disputes over diverted water that we occasionally see on Earth. But the possibility of two advanced civilisations in one solar system is perhaps a little fanciful; a more interesting question is: what happens to the other planets when they suddenly lose access to solar energy because it has all been grabbed by the advanced civilisation in their midst? Presumably, any early forms of life on those planets would be wiped out. It’s possible to imagine a Type 2 civilisation with ethical standards so high that they would not feel able to do this. In fact, various Green political parties here on Earth would be very likely to oppose it. A cosmic rerun of construction delays while new homes are found for colonies of the Great Crested Newt. (And, if you think that’s funny, just remember that the “people” in a Type 2 civilisation may look a lot more like the Great Crested Newt than they resemble you).

Clearly, a Dyson Sphere would be enormous – Freeman Dyson himself suggested that it would cover an area 600 million times that of the Earth’s surface. And the hope is that that would make them easier to see, because one of the things that searchers for extra-terrestrial life look for is a Dyson Sphere in space. It isn’t something that is likely to have come about by accident. If we see one, we can be pretty certain that we are looking at something constructed by a very advanced alien civilisation.
How far are we earthlings from being able to become a Type 2 civilisation, capable of building a Dyson Sphere? Not, as these things go, very far at all; estimates are that we may be able to construct such a thing, and thereby make use of all the energy the Sun produces, between 1,000 and 2,000 years from now. 1,000 years ago, the Chinese were the first to use gunpowder in battle (and they had flamethrowers!). King Canute married his cousin Emma of Normandy, laying the seeds for the invasion of England by the Normans in 1066. Emperor Hadrian set up the first postal system and built a wall between England and Scotland. A thousand years isn’t very long at all. You won’t be here to see it, but it’s still very imaginable. It’s in the progression to a Type 3 civilisation that the number of years involved becomes monstrous.

• Type 3 civilisations, in fact, may be at least 100,000 years ahead of us and quite possibly more. A Type 1 civilisation is able to use all the energy its planet has. A Type 2 civilisation can use all the energy produced by its star. But a Type 3 civilisation can use all the energy produced by its own galaxy. And that is a huge step up. Every star in a galaxy is producing vast amounts of energy. A Type 3 civilisation must be able to capture and use all of it.  And how many stars is that? It’s a lot harder than you might imagine to count the number of stars in a galaxy. No one has ever yet found a way to count them individually, not least because no one has ever yet found a way to see them individually. If you were to Google the question, “How many stars are there in the Milky Way?”, you’d get a variety of answers covering quite a range – it might be 100 billion, it might be 400 billion, it might be quite different from either of those numbers – because the fact is that no one knows for certain. What astronomers actually do is measure the mass of a galaxy (in itself a far from exact science) and then make some assumptions in order to deduce the number of stars represented by that mass (bearing in mind that the bulk of the mass will actually be dark matter – another mystery).

Something we can be sure of, though, is that there aren’t any Type 3 civilisations in our galaxy. How can we be so certain? Because, if there were, they would have taken all the energy from every star in the Milky Way, and that includes our Sun. We would have no solar energy at all, and we’d all be dead. And what will happen to us if a civilisation elsewhere in our galaxy is so advanced that it is about to promote itself to Type 3? Then it’s goodnight from all of us. But, if there were any chance of that happening, there would have been a Type 2 civilisation in the Milky Way Galaxy (our galaxy) for at least a thousand centuries and we would have seen its Dyson Sphere. So no need to worry for a while yet.
By the time our earthly civilisation gets around to becoming Type 3, it’s likely that it won’t be a human civilisation at all. Humans will have disappeared, replaced by some kind of mechanised being. There will be more to say about that before this chapter ends, but before we go there, let’s take a look at what other theorists have suggested might be added to the Kardashev Scale.
 
Kardashev listed only the three types of civilisation described above. Others have proposed more.

• A Type 4 civilisation would harness the energy, not simply of a whole galaxy but of a whole universe.
• A Type 5 civilisation would find that very old hat and would be taking its power from a number of universes – a “multiverse.”
• A Type 6 civilisation would have moved on to take control of space and time. Among other things, it would be capable of creating new universes. And that might be a good thing, because the chances are that by the time Earth reaches the exalted heights of a Type 6 civilisation, so many millennia will have passed that all the stars in this universe will have burned out and be cold and dead. Earthlings’ descendants will need somewhere new to live.

 
As it happens, some scientists have decided to add a Type 7 civilisation to the Kardashev Scale. What capabilities would a Type 7 civilisation have? There’s no point in even thinking about it.
 
Step back to that Type 3 civilisation, and these words:
By the time our earthly civilisation gets around to becoming Type 3, it’s likely that it won’t be a human civilisation at all.
 
What can that possibly mean? We’ll be looking at this again in Chapter 9, but here are some of the ideas that are floating around.

Read more about The Kardashev Scale here.