Michio Kaku on Extraterrestrial Civilizations: "How Advanced Could They Possibly Be?"

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"Today, every few weeks brings news of a new Jupiter-sized extra-solar planet being discovered, the latest being about 15 light years away orbiting around the star Gliese 876. The most spectacular of these findings was photographed by the Hubble Space Telescope, which captured breathtaking photos of a planet 450 light years away being sling-shot into space by a double-star system.

"But the best is yet to come. Early in the next decade, scientists will launch a new kind of telescope, the interferometry space telescope, which uses the interference of light beams to enhance the resolving power of telescopes."

— Michio Kaku, Theoretical physicist and host of BBC series Visions of the Future.

In a brilliant essay, Michio Kaku observes that although conjecture about advanced civilizations a matter of sheer speculation, we can still use the laws of quantum field theory, general relativity, thermodynamics, to place upper and lower limits on these civilizations.

Although it is impossible to predict the precise features of such advanced civilizations, their broad outlines can be analyzed using the laws of physics. No matter how many millions of years separate us from them, they still must obey the iron laws of physics, which are now advanced enough to explain everything from sub-atomic particles to the large-scale structure of the universe, through a staggering 43 orders of magnitude.

Soon, humanity may face an existential shock as the current list of a dozen Jupiter-sized extra-solar planets swells to hundreds of earth-sized planets, almost identical twins of Earth. This may usher in a new era in our relationship with the universe: we will never see the night sky in the same way ever again, realizing that scientists may eventually compile an encyclopedia identifying the precise co-ordinates of perhaps hundreds of earth-like planets.

"The Space Interferometry Mission (SIM)," Kaku writes, "to be launched early in the next decade, consists of multiple telescopes placed along a 30 foot structure. With an unprecedented resolution approaching the physical limits of optics, the SIM is so sensitive that it almost defies belief: orbiting the earth, it can detect the motion of a lantern being waved by an astronaut on Mars!

"The SIM, in turn, will pave the way for the Terrestrial Planet Finder, to be launched late in the next decade, which should identify even more earth-like planets. It will scan the brightest 1,000 stars within 50 light years of the earth and will focus on the 50 to 100 brightest planetary systems.

"All this, in turn, will stimulate an active effort to determine if any of them harbor life, perhaps some with civilizations more advanced than ours."

Kaku cites Berkeley astronomer Don Goldsmith who reminds us that the earth receives about one billionth of the suns energy, and that humans utilize about one millionth of that, consuming about one million billionth of the suns total energy.

"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." Goldsmith syas, "We've come up in energy uses in 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 civilizations."

Physicist Freeman Dyson of the Institute for Advanced Study estimates that, within 200 years or so, we should attain Type I status -a truly planetary one, which has mastered most forms of planetary energy. Type 1 energy output may be on the order of thousands to millions of times our current planetary output.They also have enough energy to alter the course of earthquakes, volcanoes, and build cities on their oceans. In fact, growing at a modest rate of 1% per year, it would take only 3,200 years to reach Type II status, and 5,800 years to reach Type III status.

The three categories of civilizations in the universe were defined by Russian astrophysicist Nicolai Kardashev, who theorized that advanced civilizations must therefore be grouped according to three types: Type I, II, and III, which have mastered planetary, stellar and galactic forms of energy, respectively.

By definition, an advanced civilization must grow faster than the frequency of life-threatening catastrophes. Since large meteor and comet impacts take place once every few thousand years, a Type I civilization must master space travel to deflect space debris within that time frame, which should not be much of a problem. Ice ages may take place on a time scale of tens of thousands of years, so a Type I civilization must learn to modify the weather within that time frame.

Global pollution is only a mortal threat for an Earth-like Type 0 civilization; a Type I civilization has lived for several millennia as a planetary civilization, necessarily achieving ecological planetary balance. Internal problems like wars do pose a serious recurring threat, but they have thousands of years in which to solve racial, national, and sectarian conflicts.

Eventually, after several thousand years, a Type I civilization will exhaust the power of a planet, and will derive their energy by consuming the entire output of their suns energy, or roughly a billion trillion trillion ergs per second.

Kaku continues his brilliant tour concluding that Civilizations beyond Type III may have enough energy to escape our dying universe via holes in space. Lastly he point out that physicist Alan Guth of MIT, one of the originators of the inflationary universe theory, has even computed the energy necessary to create a baby universe in the laboratory (the temperature is 1,000 trillion degrees, which is within the range of these hypothetical civilizations).

Of course, until someone actually makes contact with an advanced civilization, all of this amounts to speculation tempered with the laws of physics, no more than a useful guide in our search for extra-terrestrial intelligence. But one day, many of us will gaze at the encyclopedia containing the coordinates of perhaps hundreds of earth-like planets in our sector of the galaxy. Then we will wonder, what a civilization a millions years ahead of ours will look like.

— Casey Kazan.