Authors: Michio Kaku
Tags: #Mathematics, #Science, #Superstring theories, #Universe, #Supergravity, #gravity, #Cosmology, #Big bang theory, #Astrophysics & Space Science, #Quantum Theory, #Astronomy, #Physics
Each type of
civilization differs from the next lower type by a factor of 10 billion.
Hence, a type III civilization, harnessing the power of billions of star
systems, can use 10 billion times the energy output of a type II civilization,
which in turn harnesses 10 billion times the output of a type I civilization.
Although the gap separating these civilizations may seem astronomical, it is
possible to estimate the time it might take to achieve a type III civilization.
Assume that a civilization grows at a modest rate of 2 to 3 percent in its
energy output per year. (This is a plausible assumption, since economic growth,
which can be reasonably calculated, is directly related to energy consumption.
The larger the economy, the greater its energy demands. Since the growth of the
gross domestic product, or GDP, of many nations lies within 1 to 2 percent per
year, we can expect its energy consumption to grow at roughly the same rate.)
At this modest
rate, we can estimate that our current civilization is approximately 100 to 200
years from attaining type I status. It will take us roughly 1,000 to 5,000
years to achieve type II status, and perhaps 100,000 to 1,000,000 years to
achieve type III status. On such a scale, our civilization today may be
classified as a type 0 civilization, because we obtain our energy from dead
plants (oil and coal). Even controlling a hurricane, which can unleash the
power of hundreds of nuclear weapons, is beyond our technology.
To describe our
present-day civilization, astronomer Carl Sagan advocated creating finer
gradations between the civilization types. Type I, II, and III civilizations,
we have seen, generate a total energy output of roughly 10
16
, 10
26
,
and 10
36
watts, respectively. Sagan introduced a type I.i
civilization, for example, which generates 10
17
watts of power, a
type I.2 civilization, which generates 10
18
watts of power, and so
on. By dividing each type I into ten smaller subtypes, we can begin to classify
our own civilization. On this scale, our present civilization is more like a
type 0.7 civilization—within striking distance of being truly planetary. (A
type 0.7 civilization is still a thousand times smaller than a type I, in terms
of energy production.)
Although our civilization is still quite primitive, we
already see signs of a transition taking place. When I gaze at the headlines, I
constantly see reminders of this historic evolution. In fact, I feel privileged
to be alive to witness it:
*
The Internet is
an emerging type I telephone system. It has the capability of becoming the
basis of a universal planetary communication network.
*
The economy of
the type I society will be dominated not by nations but by large trading blocs
resembling the European Union, which itself was formed because of competition
from NAFTA (the countries of North America).
*
The language of
our type I society will probably be English, which is already the dominant
second language on Earth. In many third-world countries today, the upper
classes and college educated tend to speak both English and the local language.
The entire population of a type I civilization may be bilingual in this
fashion, speaking both a local language and a planetary language.
*
Nations,
although they will probably exist in some form for centuries to come, will
become less important, as trade barriers fall and as the world becomes more
economically interdependent. (Modern nations, in part, were originally carved
out by capitalists and those who wanted a uniform currency, borders, taxes,
and laws with which to conduct business. As business itself becomes more
international, national borders should become less relevant.) No single nation
is powerful enough to stop this march to a type I civilization.
*
Wars will
probably always be with us, but the nature of war will change with the
emergence of a planetary middle class more interested in tourism and the
accumulation of wealth and resources than in overpowering other peoples and controlling
markets or geographical regions.
*
Pollution will
increasingly be tackled on a planetary scale. Greenhouse gases, acid rain,
burning rain forests, and such respect no national boundaries, and there will
be pressure from neighboring nations for offending entities to clean up their
act. Global environmental problems will help to accelerate global solutions.
*
As resources
(such as fish harvests, grain harvests, water resources) gradually flatten out
due to overcultivation and over- consumption, there will be increased pressure
to manage our resources on a global scale or else face famine and collapse.
*
Information will
be almost free, encouraging society to be much more democratic, allowing the
disenfranchised to gain a new voice, and putting pressure on dictatorships.
These forces are
beyond the control of any single individual or nation. The Internet cannot be
outlawed. In fact, any such move would be met more with laughter than with
horror, because the Internet is the road to economic prosperity and science as
well as culture and entertainment.
But the
transition from type 0 to type I is also the most perilous, because we still
demonstrate the savagery that typified our rise from the forest. In some sense,
the advancement of our civilization is a race against time. On one hand, the
march toward a type I planetary civilization may promise us an era of
unparalleled peace and prosperity. On the other hand, the forces of entropy
(the greenhouse effect, pollution, nuclear war, fundamentalism, disease) may
yet tear us apart. Sir Martin Rees sees these threats, as well as those due to
terrorism, bioengineered germs, and other technological nightmares, as some of
the greatest challenges facing humanity. It is sobering that he gives us only a
fifty-fifty chance of successfully negotiating this challenge.
This may be one
of the reasons we don't see extraterrestrial civilizations in space. If they
indeed exist, perhaps they are so advanced that they see little interest in our
primitive type 0.7 society. Alternatively, perhaps they were devoured by war or
killed off by their own pollution, as they strived to reach type I status. (In
this sense, the generation now alive may be one of the most important
generations ever to walk the surface of Earth; it may well decide if we safely
make the transition to a type I civilization.)
But as Friedrich
Nietzsche once said, what does not kill us makes us stronger. Our painful
transition from type 0 to type I will surely be a trial by fire, with a number
of harrowing close calls. If we can emerge from this challenge successfully, we
will be stronger, in the same way that hammering molten steel serves to temper
it.
When a
civilization reaches type I status, it is unlikely to immediately reach for
the stars; it is more likely to stay on the home planet for centuries, long
enough to resolve the remaining nationalistic, fundamentalist, racial, and
sectarian passions of its past. Science fiction writers frequently
underestimate the difficulty of space travel and space colonization. Today, it
costs $10,000 to $40,000 per pound to put anything into near-Earth orbit.
(Imagine John Glenn made out of solid gold, and you begin to appreciate the
steep cost of space travel.) Each space shuttle mission costs upward of $800
million (if we take the total cost for the space shuttle program and divide
by the number of missions). It is likely that the cost of space travel will go
down, but only by a factor of i0 in the next several decades, with the arrival
of reusable launch vehicles (RLVs) which can be reused immediately after a
mission is complete. Through most of the twenty-first century, space travel
will remain a prohibitively expensive proposition except for the wealthiest
individuals and nations.
(There is one
possible exception to this: the development of "space elevators."
Recent advances in nanotechnology make possible the production of threads made
of superstrong and superlightweight carbon nanotubes. In principle, it is
possible that these threads of carbon atoms could prove strong enough to
connect Earth with a geosynchronous satellite orbiting more than 20,000 miles
above Earth. Like Jack and the Beanstalk, one might be able to ascend this
carbon nanotube to reach outer space for a fraction of the usual cost.
Historically, space scientists dismissed space elevators because the tension on
the string would be enough to break any known fiber.
However, carbon
nanotube technology may change this. NASA is funding preliminary studies on
this technology, and the situation will be closely analyzed over the years. But
should such a technology prove possible, a space elevator could at best only
take us into orbit around Earth, not to the other planets.)
The dream of
space colonies must be tempered by the fact that the cost of manned missions to
the Moon and the planets is many times the cost of near-Earth missions. Unlike
the Earth-bound voyages of Columbus and the early Spanish explorers centuries
ago, where the cost of a ship was a tiny fraction of the gross domestic product
of Spain and where the potential economic rewards were huge, the establishment
of colonies on the Moon and Mars would bankrupt most nations, while conferring
almost no direct economic benefits. A simple manned mission to Mars could cost
anywhere from $100 billion to $500 billion, with little to show for it
financially in return.
Similarly, one
also has to consider the danger to the human passengers. After half a century
of experience with liquid-fueled rockets, the chances of a catastrophic
failure involving rocket missions are about one in seventy. (In fact, the two
tragic losses of the space shuttle fall within this ratio.) Space travel, we often
forget, is different from tourism. With so much volatile fuel and so many
hostile threats to human life, space travel will continue to be a risky proposition
for decades to come.
On a scale of
several centuries, however, the situation may gradually change. As the cost of
space travel continues its slow decline, a few space colonies may gradually
take hold on Mars. On this time scale, some scientists have even proposed
ingenious mechanisms to terraform Mars, such as deflecting a comet and letting
it vaporize in the atmosphere, thereby adding water vapor to the atmosphere.
Others have advocated injecting methane gas into the atmosphere to create an
artificial greenhouse effect on the red planet, raising temperatures and
gradually melting the permafrost under the surface of Mars, thereby filling its
lakes and streams for the first time in billions of years. Some have proposed
more extreme, dangerous measures, such as detonating an underground nuclear
warhead beneath the ice caps to melt the ice (which could pose a health hazard
for space colonists of the future). But these suggestions are still wildly
speculative.
More likely, a
type I civilization will find space colonies a distant priority in the next few
centuries. But for long-distance interplanetary missions, where time is not so
pressing, the development of a solar/ion engine may offer a new form of
propulsion between the stars. Such slow-moving engines would generate little
thrust, but they can maintain that thrust for years at a time. These engines
concentrate solar energy from the sun, heat up a gas like cesium, and then
hurl the gas out the exhaust, giving a mild thrust that can be maintained
almost indefinitely. Vehicles powered by such engines might be ideal for
creating an interplanetary "interstate highway system" connecting the
planets.
Eventually, type
I civilizations might send a few experimental probes to nearby stars. Since the
speed of chemical rockets is ultimately limited by the maximum speed of the
gases in the rocket exhaust, physicists will have to find more exotic forms of
propulsion if they hope to reach distances that are hundreds of light-years
away. One possible design would be to create a fusion ramjet, a rocket that
scoops hydrogen from interstellar space and fuses it, releasing unlimited
amounts of energy in the process. However, proton-proton fusion is quite
difficult to attain even on Earth, let alone in outer space in a starship. Such
technology is at best another century in the future.
A type II
civilization able to harness the power of an entire star might resemble a
version of the Federation of Planets in the
Star Trek
series, without the warp drive. They have colonized a tiny
fraction of the Milky Way galaxy and can ignite stars, and hence they qualify
for an emerging type II status.
To fully utilize
the output of the Sun, physicist Freeman Dyson has speculated that a type II
civilization might build a gigantic sphere around the Sun to absorb its rays.
This civilization might, for example, be able to deconstruct a planet the size
of Jupiter and distribute the mass in a sphere around the Sun. Because of the
second law of thermodynamics, the sphere would eventually heat up, giving off a
characteristic infrared radiation that could be seen from outer space. Jun
Jugaku of the Research Institute of Civilization in Japan and his colleagues
have searched the heavens out to 80 light-years to try to locate other such
civilizations and have found no evidence of these infrared emissions (although
remember that our galaxy is 100,000 light-years across).