Write your abstract here.PART II - Michio Kaku''s Civilizations of the Cosmos. By
definition, Kaku proposes that
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 to million
years, a Type I civilization must master space travel to deflect space
debris within that time, which should not be much of a problem. Ice
ages may take place on a time scale of tens of thousands of years, and
so a Type I civilization must learn to modify the weather within that
period.
Artificial and internal catastrophes must also be negotiated. Global
pollution is a mortal threat for a Type 0 civilization, but not a Type
I civilization, which has lived for several millennia as a global force
and necessarily achieved ecological balance with its home planet.
Internal problems such as wars do present a serious recurring threat,
but emerging civilizations have thousands of years in which to solve
their racial, national, and sectarian conflicts. Since it would take
centuries or even millennia for a Type I civilization to terraform
nearby planets, its peoples will have plenty of time to work out their
internal differences on the same planet before they finally leave the
mother planet in any significant numbers.
The only serious threat to a Type II civilization would be a nearby
supernova explosion, whose sudden eruption could scorch their planet in
a withering blast of life-destroying gamma-rays. The most potentially
interesting civilization is a Type III civilization, "for it is truly
immortal. It has exhausted the power of a single star, and has reached
out to other star systems. No natural catastrophe known to science has
the capacity to destroy a Type III civilization."
Faced with an exploding supernova, a Type 111 would have several
alternatives, for example altering the evolution of a dying red giant
star which is about to explode, or leaving this particular star system
and terraforming a nearby planetary system. Kaka continues:
However, there are roadblocks to an emerging Type III
civilization. Eventually, it bumps into Einstein''s theory of
relativity. Nothing can travel faster than light, which is about
300,000km a second (for a possible loophole, see the end of this
article). Since the universe is so vast and space is so empty, this
absolute speed limit tends to hold back a civilization''s successful
expansion. Dyson estimates that this roadblock may delay the transition
from a Type II to a Type III civilization by perhaps a million years or
more.
So what is the most efficient way of exploring the hundreds of billions of stars in the galaxy?
Kaku writes that the solution is to to send fleets of ''von Neumann
probes'' throughout the galaxy (named after John von Neumann, the
Hungarian-born mathematician who defined the mathematical laws of
self-replicating systems).
A von Neumann probe is a robot designed to reach distant star
systems and create factories that will reproduce copies of themselves
by the thousands. For von Neumann probes, a planet is a less ideal
destination than a dead moon; these have no atmosphere and no erosion,
which means the probes can easily land and take off and can ''live off
the land'', using naturally occurring deposits of iron, nickel and other
minerals to build replicants for dispersal in search for other star
systems.
Arizona State University physicist Paul Davies, has even raised the
possibility that a von Neumann probe could be resting on our own Moon,
left over from a previous visitation in our system aeons ago -the plot
foundation of the film, 2001: A Space Odyssey. Originally, apparently,
Stanley Kubrick began the film with a series of scientists explaining
how von Neumann-like probes would be the most efficient method of
exploring space. Unfortunately, at the last minute, Kubopening segment from his film, and the famous monoliths – von Neumann
probes – became mystical entities that triggered human evolution.
The
irony of a search for a Type III civilization is that they probably
wouldn''t resemble anything we''d be able to recognise immediately.
Kaku concludes that that "one day, many of us could gaze at the
encyclopadia that contains the coordinates of perhaps hundreds of
Earth-like planets in our sector of the galaxy. Then we will ponder
with wonder, as Sagan did, what an intelligent civilization a millions
years ahead of ours will look like."