View Full Version : How Advanced Can a Civilization Become?

2005-Sep-08, 03:24 AM
SUMMARY: Dr. Michio Kaku, the author of Hyperspace and Einstein's Cosmos speaks with Astrobiology Magazine about the limits of civilization in the Universe. Even limited by what we know about the laws of physics, civilizations could eventually control the entire energy output of their planet, star, and even galaxy. Not only that, but there are ways astronomers could search the skies for evidence of these civilizations.

View full article (http://www.universetoday.com/am/publish/advanced_civilization_become.html)
What do you think about this story? post your comments below.

2005-Sep-08, 12:56 PM
Kaku is my kind of guy with my kind of optimism. I have been trying to get us started in his direction with my interstellar transportation system described in inputs to other threads.

2005-Sep-08, 02:02 PM
Kaku is one of my heroes; but I think the road to becoming an advanced civilisation will be rockier than he suggests.

For instance the Earth is currently a Kardashev class 0 type civilisation; but it is not really true to say that we only use a millionth of the energy that falls incident on the Earth. In fact we 'use' about a third; it takes that much energy to maintain our biosphere.

In order to become a type I civilisation we would need to use all that incident energy for the purposes of civilisation; the only way I can imagine doing that would be to build a giant circular solar power collector with the same diameter as Earth directly between the Earth and the Sun; if you then tried to supprt the population of our planet using the power collected from this disc you would find that it would take a lot more energy than a millionth fraction.

Actually the energy could be used for various purposes before it reaches the Earth, and this could allow our planet to be heated by the waste heat of these processes. At this moment in time we can only speculate as to what an advanced civilisation would do with all that power; but rest assured it would produce a lot of waste heat at the end of the day.

In fact this model of a Kardashev Class I civilisation is unlikely; our civilisation is more likely to be spread out among many worlds and habitats in the Solar system when it passes the energy requirements for this class, which thankfully will allow the Earth to remain a little more recognisable in the process.

If we then consider the development of a Kardashev type II civilisation; in order to utilise all of the energy of a single star the construction of a Dyson shell is mandatory. This would require the dismantling of most, if not all of the planets. As you can imagine this process would not happen over night; in fact, with the best will in the world, it would occur exponentially, so that the first few thousand years would entail a very slow growth in the construction of solar energy collectors, and an almost imperceptible decrease in the diameter of the inner planets. The, suddenly, toward the end of the process, the dismantling of worlds and the construction of the Dyson shell would rapidly accelerate.

Once again this is not a very realistic scenario, and a civilisation will probably be spread out among several- or even innumerable- stars before that civilisation reaches an energy use equivalent to one single star's output.
Additionally, the local stars are not the only source of energy; other possibilities include fission, fusion, and direct conversion of matter to energy (perhaps using a captive mini-black-hole.

A Kardashev II class civilisation is unlikely to develop within a single system, in other words; and as Kaku suggests, a type III would be millions of years in the making, if it were feasible at all.