Alchemy. The link between the immemorial magic arts and modern science. Humankind’s first systematic effort to unlock the secrets of matter by reproducible experiment.

As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didn’t make a turning point of it, we were assigned to the humanities, to poetry, philosophy, painting—the nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.

At the origin, the [space travel] pioneers of the greatest adventure of all times were motivated by the drive to explore, by the pure spirit of conquest, by the lofty desire to open up new fields to human genius. … From their exceptional journeys, they all came back with the revelation of beauty. Beauty of the black sky, beauty and variety of our planet, beauty of the Earth seen from the Moon, girdled by a scintillating belt of equatorial thunderstorms. They all emphasize that our planet is one, that borderlines are artificial, that humankind is one single community on board spaceship Earth. They all insist that this fragile gem is at our mercy and that we must all endeavor to protect it.

Before I flew I was already aware of how small and vulnerable our planet is; but only when I saw it from space, in all its ineffable beauty and fragility, did I realize that humankind’s most urgent task is to cherish and preserve it for future generations.

Engineering is the professional art of applying science to the optimum conversion of the resources of nature to the uses of humankind.

Few people doubt that the Apollo missions to the Moon as well as the precursory Mercury and Gemini missions not only had a valuable role for the United States in its Cold War with the Soviet Union but also lifted the spirits of humankind. In addition, the returned samples of lunar surface material fueled important scientific discoveries.

For me and many scientists, the understanding of nature is based upon scientific investigations that add to humankind’s ever increasing fund of knowledge. The fund is ever changing as new generations of scientists add to, debate, and reinterpret the data.

I see the whole of humankind becoming a single, integrated organism. … I look upon each of us as I would an individual cell in the organism, each of us playing his or her respective role.

The efforts of most human-beings are consumed in the struggle for their daily bread, but most of those who are, either through fortune or some special gift, relieved of this struggle are largely absorbed in further improving their worldly lot. Beneath the effort directed toward the accumulation of worldly goods lies all too frequently the illusion that this is the most substantial and desirable end to be achieved; but there is, fortunately, a minority composed of those who recognize early in their lives that the most beautiful and satisfying experiences open to humankind are not derived from the outside, but are bound up with the development of the individual's own feeling, thinking and acting. The genuine artists, investigators and thinkers have always been persons of this kind. However inconspicuously the life of these individuals runs its course, none the less the fruits of their endeavors are the most valuable contributions which one generation can make to its successors.

The equation of evolution with progress represents our strongest cultural impediment to a proper understanding of this greatest biological revolution in the history of human thought.

The famous set of pictures taken from the moon, [celebrate] the birth of a global consciousness that will help build a peaceful future for humankind. That future is in the hands of those who dedicate their lives to explore Teilhard de Chardin’s three infinities: the infinitely big, the infinitely small, and the infinitely complex. And from all the beauty they discover while crossing perpetually receding frontiers, they develop for nature and for humankind an infinite love.

The idea that the Earth is alive may be as old as humankind. The ancient Greeks gave her the powerful name Gaia and looked on her as a goddess.

We should have positive expectations of what is in the universe, not fears and dreads. We are made with the realization that we’re not Earthbound, and that our acceptance of the universe offers us room to explore and extend outward. It’s like being in a dark room and imagining all sorts of terrors. But when we turn on the light – technology - suddenly it’s just a room where we can stretch out and explore. If the resources here on Earth are limited, they are not limited in the universe. We are not constrained by the limitations of our planet. As children have to leave the security of family and home life to insure growth into mature adults, so also must humankind leave the security and familiarity of Earth to reach maturity and obtain the highest attainment possible for the human race.

We urgently need [the landmark National Ocean Policy] initiative, as we use our oceans heavily: Cargo ships crisscross the sea, carrying goods between continents. Commercial and recreational fishing boats chase fish just offshore. Cruise ships cruise. Oil and gas drilling continues, but hopefully we will add renewable energy projects as well. Without planning, however, these various industrial activities amount to what we call “ocean sprawl,” steamrolling the resources we rely upon for our livelihoods, food, fun, and even the air we breathe. While humankind relies on many of these industries, we also need to keep the natural riches that support them healthy and thriving. As an explorer, I know firsthand there are many places in the ocean so full of life that they should be protected.

Whatever terrain the environmental historian chooses to investigate, he has to address the age-old predicament of how humankind can feed itself without degrading the primal source of life. Today as ever, that problem is the fundamental challenge in human ecology, and meeting it will require knowing the earth well—knowing its history and knowing its limits.