Who Speaks for Earth
A transcript from the final program
in the Cosmos television series first shown during 1980
on the Public Broadcasting System in the United States. This
version differs from that in the published book of the same
The civilization now in jeopardy is all humanity. As the
ancient myth makers knew, we are children equally of the earth and
sky. In our tenure of this planet, we have accumulated dangerous,
evolutionary baggage -- propensities for aggression and ritual,
submission to leaders, hostility to outsiders, all of which puts our
survival in some doubt. We have also acquired compassion for others,
love for our children, a desire to learn from history and experience,
and a great, soaring passionate intelligence -- the clear tools for
our continued survival and prosperity.
Which aspects of our nature will prevail is uncertain, particularly
when our visions and prospects are bound to one small part of the
small planet earth. But, up and in the cosmos an inescapable
perspective awaits. National boundaries are not evidenced when we view
the earth from space. Fanatic ethnic or religious or national
identifications are a little difficult to support when we see our
planet as a fragile, blue crescent fading to become an inconspicuous
point of light against the bastion and citadel of the stars.
There are not yet obvious signs of extraterrestrial intelligence, and
this makes us wonder whether civilizations like ours rush inevitably
into self-destruction. I dream about it . . . and sometimes they are
In the vision of the dream I once imagined myself searching for other
civilizations in the cosmos. Among a hundred billion galaxies and a
billion trillion stars, life and intelligence should have arisen in
many worlds; some worlds are barren and desolate. On them life never
began or may have been extinguished in some cosmic catastrophe. There
may be worlds rich in life not yet evolved to intelligence and high
technology; there may be civilizations that achieved technology and
then promptly used it to destroy themselves; and, perhaps, there are
also beings who learn to live with their technology and themselves,
beings who endure and become citizens of the cosmos.
Immersed in these thoughts, I found myself approaching a world that
was clearly inhabited, a world I had visited before. I saw a planet
encompassed by light and recognized the signature of intelligence.
But, suddenly, darkness -- total and absolute.
In my dream, I could read the "Book of Worlds", a vast
encyclopedia of a billion planets within the Milky Way. What could the
galactic computer tell me about this now darkened world? They must
have survived some earlier catastrophe. Their biology was different
from ours. High technology. I wondered what those lights had been for;
there must have been signs they were in trouble. The possibility of
survival in a century -- less than one percent, not very good odds.
Communications interrupted. Their world society had failed; they had
made the ultimate mistake. I felt a longing to return to earth.
The television transmissions from earth rushed past me, expanding
away from our planet at the speed of light. Then suddenly -- silence,
total and absolute. But the dream was not yet done.
Had we destroyed our home? What had we done to the earth? There had
been many ways for life to perish at our hands; we had poisoned the
air and water; we had ravaged the land. Perhaps we had changed the
climate. Could it have been a plague or nuclear war? I remembered the
galactic computer. What would it say about the earth?
There was our region of the galaxy; there was our world. I had found
the entry for earth: HUMANITY: THIRD FROM THE SUN. They had heard our
television broadcasts and thought them an application for cosmic
citizenship. Our technology had been growing enormously (they got that
right). Two hundred nation states, about six global powers, the
potential to become one planet. Probability of survival over a century
-- here, also, less than one percent. So, it was nuclear war, a full
There would be no more big questions, no more answers. Never again a
love or a child; no descendents to remember us and be proud; no more
voyages to the stars, no more songs from the earth.
I saw east Africa and thought, "a few million years ago we
humans took our first steps there. Our brains grew and changed. The
old parts began to be guided by the new parts, and this made us human
-- with compassion and foresight and reason. But, instead, we listened
to that reptilian voice within us, counseling fear, territoriality and
aggression. We accepted the products of science; we rejected its
Maybe the reptiles will evolve intelligence once more. Perhaps, one
day, there will be civilizations again on earth. There will be life,
there will be intelligence; but there will be no more humans -- not
here, not in a billion worlds.
Every thinking person fears nuclear war, and every technological
nation plans for it. Everyone knows its madness, and every country has
an excuse. There is a dreary chain of causality. The Germans were
working on the bomb at the beginning of World War II, so the Americans
had to make one first. If the Americans had one, the Russians had to
have one. Then the British, the French, the Chinese, the Indians, the
Pakistanis. Many nations now collect nuclear weapons; they are easy to
make. You can steal fissionable material from nuclear reactors.
Nuclear weapons have almost become a home industry.
The conventional bombs of World War II were called "blockbusters",
filled with 20 tons of TNT they could destroy a city block. All the
bombs dropped on all the cities during World War II amounted to some 2
million tons of TNT -- two megatons. Coventry, Rotterdam, Dresden and
Tokyo -- all the death that rained from the skies between 1939 and
1945 -- a hundred thousand blockbusters, two megatons. Today, two
megatons is the equivalent of a single thermonuclear bomb -- one bomb
with the destructive force of the second world war. But there are tens
of thousands of nuclear weapons. The missile and bomber forces in the
Soviet Union and United States have warheads aimed at over 15,000
designated targets. No place on the planet is safe.
The energy contained in these weapons -- genies of death, patiently
awaiting the rubbing of the lamps -- totals far more than 10,000
megatons; but, with the destruction concentrated efficiently, not over
six years but over a few hours. A blockbuster for every family on the
planet; a World War II every second for the length of a lazy
The bomb dropped on Hiroshima killed 70,000 people. In a full nuclear
exchange, in the paroxysm of global death, the equivalent of a million
Hiroshimas would be dropped all over the world. And, in such an
exchange not everyone would be killed by the blast and the fire storm
and the immediate radiation. There would be other agonies. The loss of
loved ones; the legions of the burned and blinded and mutilated;
disease; plague; long-lived radiation poisoning the soil and the
water; the threat of stillbirths and malformed children; and, the
hopeless sense of a civilization destroyed for nothing. The knowledge
that we could have prevented it and did nothing.
The global balance of terror pioneered by the United States and the
Soviet Union holds hostage all the citizens of the earth. Each side
consistently probes the limits of the other's tolerance -- like the
Cuban missile crisis, the testing of anti-satellite weapons, the
Vietnam and Afghanistan wars. The hostile military establishments are
locked in some ghastly mutual embrace, each needs the other but the
balance of terror is a delicate balance with very little margin for
miscalculation. And the world impoverishes itself by spending half a
trillion dollars a year in preparations for war and by employing
perhaps half the scientists and high technologists on the planet in
How would we explain all this to a dispassionate, extraterrestrial
observer? What account would we give of our stewardship of the planet
We have heard the rationales offered by the superpowers. We know who
speaks for the nations; but who speaks for the human species? Who
speaks for earth?
From an extraterrestrial perspective, our global civilization is
clearly on the edge of failure and the most important task it faces is
preserving the lives and well-being of its citizens and the future
habitability of the planet. If we are willing to live with the growing
likelihood of nuclear war, shouldn't we also be willing to explore
vigorously every possible means to prevent nuclear war? Shouldn't we
consider in every nation major changes in the traditional ways of
doing things, a fundamental restructuring of economic, political,
social and religious institutions? We have reached a point where there
can be no more special interests or special cases. Nuclear arms
threaten every person on the earth.
Fundamental changes in society are sometimes labeled impractical or
contrary to human nature: as if nuclear war were practical or as if
there were only one human nature. But fundamental changes can clearly
be made. We are surrounded by them. In the last two centuries abject
slavery, which was with us for thousands of years, has almost entirely
been eliminated in a stirring world wide revolution. Women,
systematically mistreated for millennia, are gradually gaining the
political and economic power traditionally denied to them. And some
wars of aggression have recently been stopped or curtailed because of
a revulsion felt by the people in the aggressor nations. The old
appeals to racial, sexual and religious chauvinism and to rabid
nationalism are beginning not to work. A new consciousness is
developing which sees the earth as a single organism and recognizes
that an organism at war with itself is doomed. We are one planet.
One of the great revelations of the age of space exploration is the
image of the earth, finite and lonely, somehow vulnerable, bearing the
entire human species through the oceans of space and time. But this is
an ancient perception . . . history is full of people who, out of fear
or ignorance or the lust for power, have destroyed treasures of
immeasurable value which truly belong to all of us. We must not let it
We have considered the destruction of worlds and the end of
civilizations, but there is another perspective by which to measure
human endeavors. Let me tell you a story -- about the beginning.
Some fifteen billion years ago our universe began with the mightiest
explosion of all time. The universe expanded, cooled and darkened.
Energy condensed into matter, mostly hydrogen atoms, and these atoms
accumulated into vast clouds; rushing away from each other they would
one day become the galaxies. Within these galaxies the first
generation of stars was borne, kindling the energy hidden in matter,
flooding the cosmos with light. Hydrogen atoms that made suns and
starlight. There were in those times no planets to receive the light,
no living creatures to admire the radiance of the heavens. But deep in
the stellar furnaces nuclear fusion was creating the heavier atoms --
carbon and oxygen, silicon and iron. These elements, the ash left by
hydrogen, were the raw materials from which planets and life later
At first, the heavier elements were trapped in the hearts of the
stars, but massive stars soon exhausted their fuel and in their death
throes returned most of their substance back into space. Interstellar
gas became enriched with heavy elements.
In the Milky Way galaxy the matter of the cosmos was recycled into
new generations of stars now rich in heavy atoms, a legacy from their
stellar ancestors. And in the cold of. interstellar space great
turbulent clouds were gathered. by gravity and stirred by starlight.
In the depths the heavy atoms condensed into grains of rocky dust and
ice, complex carbon-based molecules. In accordance with the laws of
physics and chemistry, hydrogen atoms had brought forth the stuff of
life. In other clouds more massive aggregates of gas and dust formed
later generations of stars. As new stars were formed, tiny
condensations of matter accreted near them, inconspicuous moats of
rock and material ice and gas that would become the planets And on
these worlds, as in interstellar clouds, organic molecules formed made
of atoms that had been cooked inside the stars. In the tide pools and
oceans of many worlds molecules were destroyed by sunlight and
assembled by chemistry. One day, in these natural experiments, a
molecule arose that quite by accident was able to make crude copies of
As time passed self-replication became more accurate as molecules
that copied better produced more copies. Natural selection was under
way. Elaborate molecular machines had evolved slowly, imperceptibly --
life had begun. Collectives of organic molecules evolved into
one-celled organisms. These produced multi-celled colonies. Various
parts became specialized organs. Some colonies attached themselves to
the sea floor; others swam freely. Eyes evolved and now the cosmos
could see. Living things moved on to colonize the land. Reptiles held
sway for a time and gave way to small, warm blooded creatures with
bigger brains who developed dexterity and curiosity about their
environment. They learned to use tools and fire and language -- star
stuff, the ash of stellar alchemy had emerged into consciousness.
We are a way for the cosmos to know itself. We are creatures of the
cosmos and always hunger to know our origins, to understand our
connection with the universe. How did everything come to be? Every
culture on the planet has devised its own response to the riddle posed
by the universe. Every culture celebrates the cycles of life and
nature. There are many different ways of being human.
But, an extraterrestrial visitor examining the differences among
human societies would find those differences trivial compared to the
similarities. We are one species. We are star stuff harvesting star
light. Our lives, our past and our future are tied to the sun, the
moon and the stars. Our ancestors knew that their survival depended on
understanding the heavens. They built observatories and computers to
predict the changing of the seasons by the motions in the skies. We
are all of us descended from astronomers.
The discovery that there is order in the universe, that there are
laws of nature, is the foundation on which science is built on today.
Our conception of the cosmos -- all of modern science and technology
--is traced back to questions raised by the stars. Yet, even 400 years
ago we had still no idea of our place in the universe. The long
journey to that understanding required both an unflinching respect for
the facts and a delight in the natural world.
Johannes Kepler wrote: "We do not ask for what useful purpose
the birds do sing, for song is their pleasure since they were created
for singing. Similarly, we ought not to ask why the human mind
troubles to fathom the secrets of the heavens. The diversity of the
phenomena of nature is so great and the treasures hidden in the
heavens so rich precisely in order that the human mind shall never be
lacking in fresh enrichment."
It is the birthright of every child to encounter the cosmos anew in
every culture in every age. When this happens to us, we experience a
deep sense of wonder. The most fortunate among us are guided by
teachers who channel this exhilaration. We are born to delight in the
world; we are taught to distinguish our preconceptions from the truth.
Then, new worlds are discovered as we decipher the mysteries of the
Science is a collective enterprise which embraces many cultures and
spans the generations in every age and sometimes in the most unlikely
places there are those who wish with a great deal of passion to
understand the world. There is no way of knowing where the next
discovery will come from. What dream of the mind's eye will remake the
world. These dreams begin as impossibilities. Once, even to see a
planet through a telescope was an astonishment; but we studied these
worlds, figured out how they moved in their orbits, and soon we were
planning voyages of discovery beyond the earth and sending robot
explorers to the planets and the stars.
We humans long to be connected with our origins so we create rituals.
Science is another way to experience this longing. It also connects us
with our origins, and it too has its rituals and its commandments. Its
only sacred truth is that there are no sacred truths. All assumptions
must be critically examined. Arguments from authority are worthless.
Whatever is inconsistent with the facts -- no matter how fond of it we
are -- must be discarded or revised. Science is not perfect. It is
often misused. It is only a tool, but it is the best tool we have --
self-correcting, ever changing, applicable to everything. With this
tool we vanquish the impossible; with the methods of science we have
begun to explore the cosmos. For the first time scientific discoveries
are widely accessible. Our machines -- the products of our science --
are now beyond the orbit of Saturn. A preliminary spacecraft
reconnaissance has been made of 20 new worlds. We have learned to
value careful observation, to respect the facts even when they are
disquieting, when they seem to contradict "conventional wisdom".
WWe depend upon free inquiry and free access to knowledge. We humans
have seen the atoms which constitute all of nature and the forces that
sculpted this work and others. We have found that the molecules of
life are easily formed under conditions throughout the cosmos. We have
mapped the molecular machines of the heart of life. We have discovered
a microcosm in a drop of water; we have peered into the bloodstream
and down on the stormy planet to see the earth as a single organism.
We have found volcanoes on other worlds and explosions on the sun,
studied comets from the depths of space and traced their origins and
destinies; listened to pulsars and searched for other civilizations.
We humans have set foot on another world in a place called the Sea of
Tranquility, an astonishing achievement for creatures such as we,
whose earliest footsteps three and one-half million years old are
preserved in the volcanic ash of east Africa. We have walked far.
These are some of the things that hydrogen atoms do given fifteen
billion years of cosmic evolution. It has the sound of epic myth, but
it is simply a description of the evolution of the cosmos as revealed
by science in our time. And we, we who embody the local eyes and ears
and thoughts and feelings of the cosmos, we have begun at least to
wonder about our origins -- star stuff contemplating the stars,
organized collections of ten billion billion billion atoms,
contemplating the evolution of nature, tracing that long path by which
it arrived at consciousness here on the planet earth, and perhaps
throughout the cosmos.
Our loyalties are to the species and to the planet. We speak for
earth. Our obligation to survive and flourish is owed not just to
ourselves but also to that cosmos ancient and vast from which we