Conceptual computer artwork of multiple universes: Some physicists believe that there are an infinite number of parallel universes, created for each possible quantum mechanical outcome. The collective name for these universes is the multiverse.
Credit: Mehau Kulyk/SPL
Ask the average scientist about the possibility of an encounter with an extra-terrestrial lifeform, and it's likely you'll find you've prompted 'the giggle factor'. After rolling their eyes, they remind you that the distances between stars are so vast, it's virtually impossible for any aliens to visit us.
But a potential flaw is assuming an extraterrestrial civilisation would be only a few hundred years ahead of us in technology. How about civilisations that may be a million years ahead of ours?
The late scientist and author Carl Sagan once asked: "What does it mean for a civilisation to be a million years old? We have had radio telescopes and spaceships for a few decades; our technical civilisation is a few hundred years old ... an advanced civilisation millions of years old is as much beyond us as we are beyond a bushbaby or a macaque."
This question is no longer just a matter of idle speculation. Soon, humanity may face an existential shock as we discover Earth-sized twins of our planet orbiting nearby solar systems. This may usher in a new era in our relationship with the universe, so that we will never see the night sky in the same way. Realising that scientists may eventually compile an encyclopaedia identifying the precise coordinates of perhaps hundreds of Earth-like planets, gazing at the night sky, we will forever after wonder if someone is gazing back at us.
Every few weeks, yet another planet about the size of Jupiter is discovered outside our solar system, adding to the list of several hundred extrasolar planets that have been discovered in the short period we've been searching. The problem is, most are too large to sustain the kind of complex life that, from our one example here on Earth, we know.
But over the next few years, new spaceborne telescopes will finally become powerful enough to identify twins of Earth. The Kepler telescope, to be launched in 2008, will probably be able to identify terrestrial planets – rocky worlds rather than gas giants like Jupiter and Saturn. Until 2012 it will scan as many as 100,000 Sun-like stars up to 2,000 light years away, and perhaps identify hundreds of Earth-like worlds by detecting the slight loss of light they cause as they pass in front of their mother star. Kepler will hopefully identify 185 such planets with less than 1.3 times the radius of Earth, and as many as 640 terrestrial planets less than 2.2 times.
Kepler will pave the way for the Terrestrial Planet Finder, expected to be launched in about 2014, which should identify an even greater number of Earth-like planets. It will scan the brightest 1,000 stars within 50 light years of our tiny home world, and focus on the 50 to 100 brightest planetary systems. Also, it will analyse the faint light reflected from these planets to determine if they can support the organic chemicals that make life possible.
All this, in turn, will stimulate an active effort to discover if any of them harbour life, perhaps some with civilisations more advanced than ours. Although it's impossible to predict exact features of such civilisations, their broad outlines can be analysed using the laws of physics. No matter how many aeons separate us from them, they still must obey the laws of physics – which we have determined to such an extent that we can explain the behaviour of the cosmos from the subatomic world to the large-scale structure of the universe, through a staggering 43 orders of magnitude (a factor of 10 million billion billion billion billion).
Civilisations may be ranked by their energy consumption, using the following principles:
• The four laws of thermodynamics describe transport of heat and work. Even an advanced civilisation is bound by the laws of thermodynamics, especially the First and Second, and can hence be ranked by the energy at its disposal. The first law states that "energy can be changed from one form to another, but cannot be created or destroyed". While, "in all energy exchanges, if no energy enters or leaves the system, the total amount of disorder always increases" is the second law.
• The laws of stable matter. Matter in the universe clumps into three large groupings: planets, stars and galaxies. This is a well-defined structural product of stellar and galactic evolution, thermonuclear fusion, and so on. Thus, the energy of a hyper-advanced civilisation will also be based on three distinct types, and this places upper limits on their rate of energy consumption.
• The laws of planetary evolution. Any advanced civilisation must grow in energy consumption faster than the frequency of life-threatening catastrophes, such as meteor impacts, ice ages, supernova explosions, and so on. If their growth rate stays any slower, they are doomed to extinction. Thus, this places mathematical lower limits on the growth rates of these civilisations.
In a seminal paper published in 1964 in the Journal of Soviet Astronomy, Russian astrophysicist Nicolai Kardashev theorised that advanced civilisations must thus be grouped according to three Types: I, II and III, signifying mastery of, respectively, planetary, stellar and galactic forms of energy usage. He calculated that the energy consumption of these three types of civilisations would be separated by a factor of about 10 billion.
Human civilisation has only recently begun to master planetary energies: fossil fuels, passive solar, wind, geothermal and nuclear fission, and may one day soon crack nuclear fusion. But how long will it take to reach Type II and III status? Less time than most realise.
Our entire planetary energy production is now about 10 billion billion ergs per second (an erg is a unit of measurement, equal to 10-7 joules). That sounds like a lot, but it's actually a small fraction of the energy we receive from the Sun. The Earth is bathed with about one billionth of its mother star's energy – we utilise about one millionth of that.
But our energy growth is rising exponentially, and we can calculate how long it will take to rise to Type II or III status. "Look how far we have come in energy uses once we figured out how to manipulate energy, how to get fossil fuels really going, and how to create electrical power from hydropower, and so forth," says Donald Goldsmith, a University of California at Berkeley astronomer and author. "We've come up in energy uses by a remarkable amount in just a couple of centuries compared to billions of years our planet has been here ... and this same sort of thing may apply to other civilisations."
Freeman Dyson, a physicist at the Institute for Advanced Study in Princeton, New Jersey, estimates that, within a century or two, we should attain Type I status. In fact, growing at a modest rate of 1 per cent per year, Kardashev estimated that it would take only 3,200 years to reach Type II status, and 5,800 years to reach Type III status.
Well written, but it does
Well written, but it does make the wild assumption of a linear growth in energy usage which is illogical. In the short run we'll learn to live within the parameters of our ecosystem or suffer the collapse that's inevitable for any species that doesn't. In the long run, we have no more clue as to the form an advanced civilization will take than that hill of ants. Will there be any outward sign of energy usage, communication or any other technology that we or our toys could recognize ? I doubt it.
Re: Well written...
Statistics of our energy consumption up to now agree with your assertion that future growth will not be linear. In fact, if compressed over time, our energy use has grown almost exponentially (non-linear). This continual growth in energy use will not change except to say that the sources will, as will the consequences of that usage. One can imagine that if left unrestrained, our energy consumption may be the motivation for the people of our planet to jump to these next phases of development, but these arguments are somewhat linear in and of themselves. There are many things that could impede our growth as a planetary civilisation, i.e., a super solar flare, an errant asteroid, diseases, uncontrolled aggression (wars), global warming at an un-predicted scale, famine, etc. So from an optimists point of view, if all of these things are avoidable then what? What would become of us? To speculate is grand, but also worthy of our consideration.
Very nice piece; reminds me
Very nice piece; reminds me a lot of the Issac Asminov book "The Last Question"
I'll wonder if we're not a little closer to the "Making an universe" as suggested. What happens if we technology comes sooner than expected: say we develop hypergate capability in a couple of hundred years.
There is even suggestion that Moore's Law may see us reach a singularity of informational processing power: a few hundred years we could have power to catalogue every particle in the universe!
Also; couldn't the nanoscale Von Neuman probes be better known to us as virii? They could either produce biogensis in uninhabited planets by seeding thier DNA, or if inhabited already by a rival Type II civilization even become the source of virulent diseases! Perhaps our location on the edge of the galaxy has spared us from too much crossfire? :)
Von Nueman
Is it narrow minded to think there is a possibility that our DNA may have been the result of a Von Neuman style endeavor? I have little doubt that there is itellegent life elswhere. The issue we face is one that should clearly humble all humans and that is the possibility that we are just in the infancy of that experiment. Many civilisations will rise and fall and many billions of lives will be expended in the seemingly futile excercise of supporting societal methodologies that are destined to fail if for no other reason than we need to find 1,000 ways that don't work. (Thanks, Edison)
One of the hardest things to swallow is that we feel that our social advancement has made us beleive that we are approacing the panacea of long fruitful lives made possible by the state. The reality of it may very well be that while we are the most advanced society we know of, we may very well have discovered the best way to do things as far as our intellegence will allow. The globalization of economies is certainly inevitable, but the persons at the top of any social food chain are only going to be as good as the evolutionary ladder allows. Unfortunately for us, at this stage of our evolution, Incorruptability does not really exist. A very significant increase in the average intellectual capacity must occur before we as a species will be able to even consider infection the rest of the galaxy. At that point we will be smart enough,(just barely) to realize how completely clueless we really are. With the type of power conversion at the behest of even a fledgling class II civilisation, even the best intellects of our planet would lack, by a hundred generations, the ability to divine it's proper usage. I am sorry if this seems to be a gloomy outlook, but it really is not. I beleive in this species ability to break into the galaxy and colonize to protect the logevity of the species, I just really can't find any individual that I would trust on this planet with the kind of power, and even worse, put it up to a vote. The populous is far too malliable to have at the helm of any real power.
Concluding this train of thought, we have come a pretty good long ways since the discovery of fire, but we still burn ourselves with it. Just because we have discovered fire, does not mean we control it effectively. You don't need to look much past California to tell that. No, when we can't solve situations like the abject poverty that stranded thousands at the superdome, The prayers that I say at night are "please do not, under any circumstances allow power of that magnitude to be wielded by anyone on this planet."
Why do you use ergs to
Why do you use ergs to discuss planetary energy budgets? Isn't MKS the preferred system for macro scale stuff. You wouldn't have to provide a scale factor to Joules and the non technical will more easily intuit the magnitudes involved once you tell them a Joule/second is a Watt. Think big communicate clearly.
Probes
So for all we know...we could be the offspring of those nano-probes the civilisation III dudes sent ages ago, reproducing ourselves and evolving from single-cell organisms that were contained in those nano probes, until we will have the means to communicate with dear old mom and dad...Ok lame comment (and probably getting close to some new-age religion or something).
Anyway, loved the article. Really makes you wonder about what might be out there.
thought corrupts all
why speculate? all you can do is wait and watch it unravel
also visitor referring to probes is probably right- it's all scientology.
be well
In order to keep the pace in
In order to keep the pace in energy consumption and human evolution, we as a whole must focus to solve internal problems, that as individuals we see as priority, but lack the agreement as a world society.
Poverty, crime injustice,war being our aquiles-foot and a bi-product of the way we now work, will be solved when we choose to, as one.
We already have enough food for everyone, we already have enough of everything for everyone.
A spiritual revolution is in order for us to expand the limits
of imagination.
Btw, english is my second language.
Von Neumann probes
It has been speculated that life on Earth was "seeded", perhaps from cometary debris. Are we Von Neumann probes?
Machines
Any hyper-advanced civilization would be the descendants of machines and not direct biological descendants of earlier civilizations. Biological evolution is very slow and would certainly be replaced by more rapid technological evolution. It will not be that long before we may have created machines which surpass us in all abilities including thinking, imagination, and reason. I would not expect much of anything to be retained from the biological ancestors of any hyper-advanced civilization. There would be no "probes" because there would be no need for probes. Members of the "civilization" itself would certainly have acquired capabilities exceeding any probes that could be sent out by organisms like ourselves.