Parallel Worlds (48 page)

A type II
civilization might colonize some of the planets in their solar system and even
embark upon a program to develop interstellar travel. Because of the vast
resources available to a type II civilization, they potentially might have
developed such exotic forms of propulsion as an antimatter/matter drive for
their starships, making possible travel near the speed of light. In principle,
this form of energy is i00 percent energy-efficient. It is also experimentally
possible but prohibitively expensive by type I standards (it takes an atom
smasher to create beams of antiprotons that can be used to create antiatoms).

We can only
speculate about how a type II society might function. However, it will have
millennia to sort out disputes over property, resources, and power. A type II
civilization could potentially be immortal. It is likely that nothing known to
science could destroy such a civilization, except perhaps the folly of the
inhabitants themselves. Comets and meteors could be deflected, ice ages could
be diverted by changing the weather patterns, even the threat posed by a
nearby supernova explosion could be avoided simply by abandoning the home
planet and transporting the civilization out of harm's way—or even potentially
by tampering with the thermonuclear engine of the dying star itself.

TYPE III CIVILIZATION

By the time a
society reaches the level of a type III civilization, it may begin to
contemplate the fantastic energies at which space and time become unstable. We
recall that the Planck energy is the energy at which quantum effects dominate,
and space-time becomes "foamy" with tiny bubbles and wormholes. The Planck
energy is well beyond our reach today, but that is only because we judge energy
from the point of view of a type 0.7 civilization. By the time a civilization
has reached type III status, it will have access (by definition) to energies
10 billion times 10 billion (or 10
²⁰
) those found on Earth today.

Astronomer Ian
Crawford of the University College in London, writes about type III
civilizations, "Assuming a typical colony spacing of 10 light-years, a
ship speed of 10 percent that of light, and a period of 400 years between the
foundation of a colony and its sending out colonies of its own, the
colonization wave front will expand at an average speed of 0.02 light-year a
year. As the galaxy is 100,000 light-years across, it takes no more than about 5
million years to colonize it completely. Though a long time in human terms,
this is only 0.05 percent of the age of the galaxy."

Scientists have
made serious attempts to detect radio emissions from a type III civilization
within our own galaxy. The giant Aricebo radio telescope in Puerto Rico has
scanned much of the galaxy for radio emissions at 1.42 gigahertz, near the
emission line of hydrogen gas. It has found no evidence of any radio emissions
in that band from any civilization radiating between 10
¹⁸
to 10
³⁰
watts of power (that is, from type I.2 to type II.4). However, this does not
rule out civilizations that are just beyond us in technology, from type 0.8 to
type I.i, or considerably ahead of us, such as type II.5 and beyond.

It also does not
rule out other forms of communication. An advanced civilization, for example,
might send signals by laser rather than radio. And if they use radio, they may
use frequencies other than 1.42 gigahertz. For example, they might spread their
signal out across many frequencies and then reassemble them at the receiving
end. This way, a passing star or cosmic storm would not interfere with the
entire message. Anyone listening in on this spread signal may hear only
gibberish. (Our own e-mails are broken up into many pieces, with each piece
sent through a different city, and then reassembled at the end for your PC.
Similarly, advanced civilizations may decide to use sophisticated methods to
break down a signal and reassemble it at the other end.)

If a type III
civilization exists in the universe, then one of their most pressing concerns
would be establishing a communication system connecting the galaxy. This, of
course, depends on whether they can somehow master faster-than-light
technology, such as via worm- holes. If we assume that they cannot, then their
growth will be stunted considerably. Physicist Freeman Dyson, quoting from the
work of Jean-Marc Levy-Leblond, speculates that such a society may live in a
"Carroll" universe, named after Lewis Carroll. In the past, Dyson
writes, human society was based on small tribes in which space was absolute but
time was relative. This meant that communication between scattered tribes was
impossible, and we could only venture a short distance from our birthplace
within a human lifetime. Each tribe was separated by the vastness of absolute
space. With the coming of the Industrial Revolution, we entered the Newtonian
universe, in which space and time became absolute, and we had ships and wheels
that linked the scattered tribes into nations. In the twentieth century, we
entered the Einsteinian universe, in which space and time were both relative,
and we developed the telegraph, telephone, radio, and TV, resulting in
instantaneous communication. A type III civilization may drift back to a
Carroll universe once again, with pockets of space colonies separated by vast
interstellar distances, unable to communicate because of the light barrier. To
prevent the fragmentation of such a Carroll universe, a type III civilization
might need to develop wormholes that allow for faster-than-light communication
at the subatomic level.

TYPE IV CIVILIZATION

Once I was
giving a talk at the London Planetarium, and a little boy of ten came up to me
and insisted that there must be a type IV civilization. When I reminded him
that there are only planets, stars, and galaxies, and that these are the only
platforms that allow for the germination of intelligent life, he claimed that a
type IV civilization could utilize the power of the continuum.

He was right, I
realized. If a type IV civilization could exist, its energy source might be
extragalactic, such as the dark energy we see around us, which makes up 73
percent of the matter/energy content of the universe. Although potentially an
enormous reservoir of energy—by far the largest in the universe—this
antigravity field is spread out over the vast empty reaches of the universe and
is hence extremely weak at any point in space.

Nikola Tesla,
the genius of electricity and rival to Thomas Edison, wrote extensively about
harvesting the energy of the vacuum. He believed that the vacuum hid untold
reservoirs of energy. If we could somehow tap into this source, it would
revolutionize all of human society, he thought. However, extracting this
fabulous energy would be extremely difficult. Think of searching for gold in
the oceans. There is probably more gold dispersed in the oceans than all the
gold at Fort Knox and the other treasuries of the world. However, the expense
of extracting this gold over such a large area is prohibitive. Hence, the gold
lying in the oceans has never been harvested.

Likewise, the
energy hidden within dark energy exceeds the entire energy content of the
stars and galaxies. However, it is spread out over billions of light-years and
would be difficult to concentrate. But by the laws of physics, it is still
conceivable that an advanced type III civilization, having exhausted the power
of the stars in the galaxy, may somehow try to tap into this energy to make the
transition to type IV.

INFORMATION CLASSIFICATION

Further
refinements to the classification of civilizations can be made based on new
technologies. Kardashev wrote down the original classification in the i960s,
before the explosion in computer miniaturization, advances in nanotechnology,
and awareness of the problems of environmental degradation. In light of these
developments, an advanced civilization might progress in a slightly different
fashion, taking full advantage of the information revolution we are witnessing
today.

As an advanced
civilization develops exponentially, the copious production of waste heat could
dangerously raise the temperature of the atmosphere of the planet and pose
climactic problems. Colonies of bacteria grow exponentially in a petri dish
until they exhaust the food supply and literally drown in their own waste.
Similarly, because space travel will remain prohibitively expensive for
centuries, and terraforming nearby planets, if possible, will be such an economic
and scientific challenge, an evolving type I civilization could potentially
suffocate in its own waste heat, or it could miniaturize and streamline its
information production.

To see the
effectiveness of such miniaturization, consider the human brain, which contains
about 100 billion neurons (as many as there are galaxies in the visible
universe) yet produces almost no heat. By rights, if a computer engineer today
were to design an electronic computer capable of computing quadrillions of
bytes per second, as the brain can apparently do effortlessly, it would
probably be several square blocks in size and would require a reservoir of
water to cool it down. Yet our brains can contemplate the most sublime thoughts
without working up a sweat.

The brain
accomplishes this because of its molecular and cellular architecture. First of
all, it is not a computer at all (in the sense of being a standard Turing
machine, with input tape, output tape, and central processor). The brain has no
operating system, no Windows, no CPU, no Pentium chip that we commonly
associate with computers. Instead, it is a highly efficient neural network, a
learning machine, where memory and thought patterns are distributed throughout
the brain rather than concentrated in a central processing unit. The brain does
not even compute very quickly, because the electrical messages sent down
neurons are chemical in nature. But it more than makes up for this slowness
because it can execute parallel processing and can learn new tasks at astronomically
fast speeds.

To improve on
the crude efficiency of electronic computers, scientists are trying to use
novel ideas, many taken from nature, to create the next generation of
miniaturized computers. Already, scientists at Princeton have been able to
compute on DNA molecules (treating DNA as a piece of computer tape based not on
binary os and is, but on the four nucleic acids A, T, C, G); their DNA computer
solved the traveling salesman problem for several cities (that is, calculate
the shortest route connecting
N
cities). Similarly, molecular transistors have been created in the laboratory,
and even the first primitive quantum computers (which can compute on individual
atoms) have been constructed.

Given the
advances in nanotechnology, it is conceivable that an advanced civilization
will find much more efficient ways to develop rather than to create copious
quantities of waste heat that threaten their existence.

TYPES A TO Z

Sagan introduced
yet another way of ranking advanced civilizations according to their
information content, which would be essential to any civilization contemplating
leaving the universe. A type A civilization, for example, is one that
processes io
⁶
bits of information. This would correspond to a
primitive civilization without a written language but with a spoken language.
To understand how much information is contained within a type A civilization,
Sagan used the example of the game twenty questions, where you are supposed to
identify a mysterious object by asking no more than twenty questions that can
be answered by a yes or a no. One strategy is to ask questions that divide the
world into two large pieces, such as, "Is it living?" After asking
twenty such questions, we have divided the world into 2
²⁰
pieces, or
10
⁶
pieces, which is the total information content of a type A
civilization.

Once a written
language is discovered, the total information content rapidly explodes.
Physicist Phillip Morrison of MIT estimates that the total written heritage
that survived from ancient Greece is about 10
⁹
bits, or a type C
civilization by Sagan's ranking.

Sagan estimated
our present-day information content. By estimating the number of books
contained in all the libraries of the world (measured in the tens of millions)
and the number of pages there are on each book, he came up with about 10
¹³
bits of information. If we include photographs, this might rise to 10
¹⁵
bits. This would place us as a type H civilization. Given our low energy and information
output, we can be classified as a type 0.7 H civilization.

He estimated
that our first contact with an extraterrestrial civilization would involve a
civilization of a least type 1.5 J or 1.8 K because they have already mastered
the dynamics of interstellar travel. At the minimum, such a civilization would
be several centuries to millennia more advanced than ours. Similarly, a
galactic type III civilization may be typified by the information content of
each planet multiplied by the number of planets in the galaxy capable of
supporting life. Sagan estimated that such a type III civilization would be
type Q. An advanced civilization that can harness the information content of a
billion galaxies, representing a large portion of the visible universe, would
qualify the civilization as type Z, he estimated.