– Christiaan Huygens, New Conjectures Concerning the Planetary Worlds, Their Inhabitants and Productions, c. 1690
‘To the entire world,’ added our Father the Sun, ‘I give my light and my radiance; I give men warmth when they are cold; I cause their fields to fructify and their cattle to multiply; each day that passes I go around the world to secure a better knowledge of men’s needs and to satisfy those needs. Follow my example.’
– An Inca myth recorded in ‘The Royal Commentaries’ of Garcilaso de la Vega, 1556
We look back through countless millions of years and see the great will to live struggling out of the intertidal slime, struggling from shape to shape and from power to power, crawling and then walking confidently upon the land, struggling generation after generation to master the air, creeping down into the darkness of the deep; we see it turn upon itself in rage and hunger and reshape itself anew, we watch it draw nearer and more akin to us, expanding, elaborating itself, pursuing its relentless inconceivable purpose, until at last it reaches us and its being beats through our brains and arteries . . . It is possible to believe that all the past is but the beginning of a beginning, and that all that is and has been is but the twilight of the dawn. It is possible to believe that all that the human mind has ever accomplished is but the dream before the awakening . . . Out of our . . . lineage, minds will spring, that will reach back to us in our littleness to know us better than we know ourselves. A day will come, one day in the unending succession of days, when beings, beings who are now latent in our thoughts and hidden in our loins, shall stand upon this earth as one stands upon a footstool, and shall laugh and reach out their hands amidst the stars.
– H. G. Wells, ‘The Discovery of the Future,’ Nature 65, 326 (1902)
The Cosmos was discovered only yesterday. For a million years it was clear to everyone that there were no other places than the Earth. Then in the last tenth of a percent of the lifetime of our species, in the instant between Aristarchus and ourselves, we reluctantly noticed that we were not the center and purpose of the Universe, but rather lived on a tiny and fragile world lost in immensity and eternity, drifting in a great cosmic ocean dotted here and there with a hundred billion galaxies and a billion trillion stars. We have bravely tested the waters and have found the ocean to our liking, resonant with our nature. Something in us recognizes the Cosmos as home. We are made of stellar ash. Our origin and evolution have been tied to distant cosmic events. The exploration of the Cosmos is a voyage of self-discovery.
As the ancient mythmakers knew, we are the children equally of the sky and the Earth. In our tenure on this planet we have accumulated dangerous evolutionary baggage, hereditary propensities for aggression and ritual, submission to leaders and hostility to outsiders, which place our survival in some question. But we have also acquired compassion for others, love for our children and our children’s children, a desire to learn from history, 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 vision and understanding and prospects are bound exclusively to the Earth – or, worse, to one small part of it. But up there in the immensity of the Cosmos, an inescapable perspective awaits us. There are not yet any obvious signs of extraterrestrial intelligence and this makes us wonder whether civilizations like ours always rush implacably, headlong, toward self-destruction. National boundaries are not evident when we view the Earth from space. Fanatical ethnic or religious or national chauvinisms are a little difficult to maintain 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. Travel is broadening.
There are worlds on which life has never arisen. There are worlds that have been charred and ruined by cosmic catastrophes. We are fortunate: we are alive; we are powerful; the welfare of our civilization and our species is in our hands. If we do not speak for Earth, who will? If we are not committed to our own survival, who will be?
The human species is now undertaking a great venture that if successful will be as important as the colonization of the land or the descent from the trees. We are haltingly, tentatively breaking the shackles of Earth – metaphorically, in confronting and taming the admonitions of those more primitive brains within us; physically, in voyaging to the planets and listening for the messages from the stars. These two enterprises are linked indissolubly. Each, I believe, is a necessary condition for the other. But our energies are directed far more toward war. Hypnotized by mutual mistrust, almost never concerned for the species or the planet, the nations prepare for death. And because what we are doing is so horrifying, we tend not to think of it much. But what we do not consider we are unlikely to put right.
Every thinking person fears nuclear war, and every technological state plans for it. Everyone knows it is madness, and every nation 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 Soviets had to have one, and then the British, the French, the Chinese, the Indians, the Pakistanis. . . By the end of the twentieth century many nations had collected nuclear weapons. They were easy to devise. Fissionable material could be stolen from nuclear reactors. Nuclear weapons became almost a home handicraft industry.
The conventional bombs of World War II were called blockbusters. Filled with twenty tons of TNT, they could destroy a city block. All the bombs dropped on all the cities in World War II amounted to some two million tons, two megatons, of TNT – Coventry and Rotterdam, Dresden and Tokyo, all the death that rained from the skies between 1939 and 1945: a hundred thousand blockbusters, two megatons. By the late twentieth century, two megatons was the energy released in the explosion of a single more or less humdrum thermonuclear bomb: one bomb with the destructive force of the Second World War. But there are tens of thousands of nuclear weapons. By the ninth decade of the twentieth century the strategic missile and bomber forces of the Soviet Union and the United States were aiming warheads at over 15,000 designated targets. No place on the planet was safe. The energy contained in these weapons, genies of death patiently awaiting the rubbing of the lamps, was 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 afternoon.
The immediate causes of death from nuclear attack are the blast wave, which can flatten heavily reinforced buildings many kilometers away, the firestorm, the gamma rays and the neutrons, which effectively fry the insides of passersby. A school girl who survived the American nuclear attack on Hiroshima, the event that ended the Second World War, wrote this first-hand account:
Through a darkness like the bottom of hell, I could hear the voices of the other students calling for their mothers. And at the base of the bridge, inside a big cistern that had been dug out there, was a mother weeping, holding above her head a naked baby that was burned red all over its body. And another mother was crying and sobbing as she gave her burned breast to her baby. In the cistern the students stood with only their heads above the water, and their two hands, which they clasped as they imploringly cried and screamed, calling for their parents. But every single person who passed was wounded, all of them, and there was no one, there was no one to turn to for help. And the singed hair on the heads of the people was frizzled and whitish and covered with dust. They did not appear to be human, not creatures of this world.
The Hiroshima explosion, unlike the subsequent Nagasaki explosion, was an air burst high above the surface, so the fallout was insignificant. But on March 1, 1954, a thermonuclear weapons test at Bikini in the Marshall Islands detonated at higher yield than expected. A great radioactive cloud was deposited on the tiny atoll of Rongalap, 150 kilometers away, where the inhabitants likened the explosion to the Sun rising in the West. A few hours later, radioactive ash fell on Rongalap like snow. The average dose received was only about 175 rads, a little less than half the dose needed to kill an average person. Being far from the explosion, not many people died. Of course, the radioactive strontium they ate was concentrated in their bones, and the radioactive iodine was concentrated in their thyroids. Two-thirds of the children and one-third of the adults later developed thyroid abnormalities, growth retardation or malignant tumors. In compensation, the Marshall Islanders received expert medical care.