Earlier this month a team of researchers made headlines by not finding any signs of alien life in 100,000 galaxies. Their search was based on the theories put forward by physicist Freeman Dyson in 1960.
Freeman Dyson theorized that advanced technological cultures would be limited by an ever growing demand for energy. This is the same theory that led to the idea of a “Dyson sphere” which would encase and harvest all of the energy of a star.
Russian astronomer Nikolai Kardashev expanded the idea by classifying civilizations into three groups. A type 1 civilization used all of the energy available on its planet, a type 2 would use all of the energy of its star, a type 3 would use all of the energy in its galaxy with Dyson Spheres around all of their stars.
Basically the idea is that as a civilization advanced, its energy needs would become greater and greater and eventually the massive amount of heat generated by all of that energy would be visible in the mid-infrared spectrum from a great distance. So, the authors of the recent paper were looking for galaxies that were generating more heat than they should be.
They looked at 100,000 galaxies and, while they found a few things that they couldn’t immediately explain, they did not find the Dyson mid-infrared signatures they were looking for. This led to a great deal of disappointment and invocations of the Fermi paradox (‘where is everyone’)?
However, what does not seem to have been considered is the possibility that the researchers demonstrated that Dyson and Kardashev were probably wrong.
The idea of an ever expanding demand for energy was based largely on our own experience and specifically our own experience as it was viewed in the early 1960s. Since that time our own demand for energy has continued to increase due in part to the modernization of much of the developing world and an increase in population which has passed 7 billion and is growing daily.
Population growth and energy consumption have both been hot topics for us since roughly the time Dyson put forward his theories. During that time another thing that we’ve discovered about ourselves is that as education and income levels go up the rate of reproduction goes down.
The most primal reason for reproduction is a need to preserve the species and pass on our own DNA. Beyond that, people have large numbers of children because of lack of education or superstition about birth control and because of economic uncertainty. People who live in a society where infant mortality is high and children represent income security for older people tend to have large families. As education increases, infant mortality decreases and financial insecurity is reduced the birth rate goes down as well.
It may be that the decline in birth rates as education and economic prosperity increase is unique to our culture but, if we’re assuming that energy use increases then it would seem logical that they might hit some of the same resource scarcity and environmental issues that we have.
All of this means that it is possible that a highly advanced, highly technological, presumably highly educated civilization could shrink in population, or at least slow its population growth substantially and so keep its overall energy level at a fairly low level.
Additionally, we have to assume that the highly technologically advanced culture we are looking for, one that is capable of colonizing a galaxy, is at least as advanced as we are. So, lets take a look at a few emerging human technologies and how they might impact long term population growth.
On Earth robotics and automation are rapidly replacing jobs once done by people, so lets assume that our advanced aliens have no need for manual labor and in general do not need population growth to sustain a work force.
We are on the verge of breakthroughs that could extend life expectancy substantially, so lets assume that our aliens live for a very long time. Depending on how long our aliens live, the need to have many children could be substantially reduced.
We may, in the not too distant future, be able to use genetic engineering technology to eliminate genetic illnesses as well as genetic predispositions to things like addiction. We may eventually be able to enhance human abilities to levels currently only found in comic books. So, lets assume that when our alien civilization has children it is a considered and deliberate act and those children are fairly exceptional.
If life expectancies become long enough to verge on immortality and children are carefully designed and customized, over many of generations, even the biological urge to pass on our DNA could diminish.
We also have to assume that our extremely advanced alien civilization that could be visible in infrared from thousands of light years away is good at space travel. They, presumably, have hundreds even thousands of planets they could inhabit. However, that does automatically mean a substantial increase in population.
Having lots and lots of children simply to fill empty space has never been much of a motivator, at least for humans. I live in Canada, a country larger than the United States but with a population roughly equal to California’s. There is no huge drive here to have lots of children to fill the space. There doesn’t seem to be much of a drive in the US to fill the central midwest either.
Even the idea that the geographic size of a civilization has something to do with its ‘greatness’ seems to be one that we’re leaving behind. The last large geographic empires, the British Empire and the USSR did not last long or end well.
Dyson could be right, there could be alien civilizations who have build spheres to harness the power of every star in their galaxy. However, its also possible that they stayed on one planet and resolved its need for more energy by having a smaller population. It’s possible that they live on hundreds of planets with only a few million or a few hundred million residents each, leaving the advanced aliens with a massive surplus of power and no real environmental problems to worry about. In that case there would be no need for a Dyson sphere and the energy signature that we can read from here would be minimal.
I could be wrong about all of this, I’m not a physicist and am by no means on Dyson’s level. However, my unsubstantiated assumptions seem more likely to me than the idea that there are no highly advanced civilizations in 100,000 galaxies.
Scientists currently believe that there are 20 billion "Earth-like" planets in the milky way. The chances of a planet developing an advanced civilization may be incredibly small but it seems to me that if you bought 20 billion lottery tickets per week for 100,000 weeks you would probably win something.
Maybe the recent study of the mid-infrared radiation from distant galaxies doesn’t show that there is no life out there, maybe it simply shows that Dyson and Kardashev were wrong.
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