For One Earth, Ten Thousand Fell

ONE AND ONE HUNDRED THOUSAND EARTHS

A View from the Stars – Cixin Liu

Compared to other animals, human infants are remarkably fragile. A newborn foal can stand on its own within ten minutes of birth, while a human baby must remain in its cradle for a long time, utterly dependent on the care of others for survival. Left to their own devices, they could never survive. By their own strength alone, humans can never leave the cradle.

This phenomenon is a result of evolutionary necessity. The human brain is large; if it were allowed to fully develop before birth, childbirth would be impossible. Thus, humans are born prematurely—every human infant is, in fact, a premature baby.

If we view human civilization as a whole, it too is a premature infant. Civilization has progressed far faster than natural evolution. We have entered the modern era with the brains and bodies of our primitive ancestors. And this leads to a terrifying question: without external assistance, can human civilization, like a baby, ever leave its cradle?

As things now stand, perhaps not.

In the distant future, when people look back on the history from the mid-20th century to today, the grand events that once shook the world may seem pale and distant. Only two events—barely noticed today—will grow in importance over time: 1, Humanity took its first step out of the cradle. 2, Humanity then drew that foot back in.

No amount of emphasis can overstate the significance of these two moments. Gagarin’s flight into space in 1961 may one day be seen as more pivotal than the birth of Christ, the true start of human history. Conversely, the decline of space exploration after the Apollo landings may leave a wound deeper than humanity’s expulsion from Eden.

The years between the late 1950s and early 1970s will be remembered as a golden age. Just three years after the launch of the first satellite, a human entered space. Seven years later, humans set foot on the Moon. The world was swept up in ambition; it was widely believed that Mars would be reached within a decade, and that journeys to Jupiter’s moon Europa were on the near horizon. Long before that, the audacious Orion Project had been proposed: to power a spacecraft with a series of nuclear explosions, capable of sending dozens of astronauts to the outer planets.

But soon, the Apollo program was cut short by funding shortages, and the remaining missions were canceled. Thereafter, human space exploration followed the trajectory of a stone tossed in Earth’s gravity well—soaring for a moment, then falling fast. December 1972, with the flight of Apollo 17—the final Moon landing—marked a turning point. Although space stations and space shuttles followed, along with a flood of satellites and robotic probes bringing economic returns, the nature of humanity’s space endeavor had quietly changed: the gaze of exploration turned from the stars back to Earth.

Before Apollo 17, spaceflight was humanity’s effort to leave the cradle. Afterward, it became a way to live more comfortably inside the cradle. Space efforts were reoriented toward economic returns; investment had to yield profit. The spirit of exploration was replaced by the mindset of the merchant. The wings in humanity’s heart were clipped.

In truth, looking back, did humanity ever really want to leave the cradle? The space race of the mid-20th century was driven not by dreams of the cosmos, but by the Cold War—by fear and the desire to surpass rivals, by political posturing. Humanity never sincerely viewed space as a future home.

Now, the Moon is once again a barren world, untraveled and silent. Manned missions to the planets planned by Russia and the U.S. have vanished like smoke. Europe’s ambitious “Aurora Program” to explore the solar system has been shelved. After the retirement of the Space Shuttle, even the United States—once the proud trailblazer—lost the ability to send humans to low Earth orbit for quite some time.

Why did this happen? The reasons we usually cite are technological and economic.

From a technological standpoint, it’s true: humanity does not yet possess the capabilities for large-scale development of the solar system. In propulsion—the core of space travel—we are still in the chemical age. Nuclear propulsion is essential for interplanetary journeys, but such technologies remain within the realm of science fiction.

Economically, even with current technology, launching payloads to orbit costs as much as their weight in gold; sending them to the Moon or beyond multiplies the expense tenfold. Before space development becomes industrialized, returns are minimal. Apollo cost $26 billion—more than $100 billion today—yielding just over two tons of Moon rocks. (Of course, the technological spinoffs of Apollo have benefited civilian life enormously, but those benefits are hard to quantify and cannot serve as decisive factors in political decisions.)

From these points, it seems that space development is a colossal gamble—technologically, economically, and politically. Entrusting humanity’s future to such an uncertain venture seems unacceptable.

These arguments are compelling and seem unassailable, guiding current space policy and leading to the decline we now witness.

But let us examine another grand undertaking in which humanity is investing vast resources, one widely seen as our only hope for survival: environmental protection.

In public perception, environmentalism and spaceflight seem utterly different. The latter is dramatic, high-speed, high-tech; the former is green, peaceful, philanthropic. One is seen as the realm of the rocket scientist; the other, the volunteer.

But this is just an illusion. The reality is that achieving our current environmental goals requires technologies even more difficult than large-scale spaceflight.

From a scientific standpoint, understanding Earth’s environment is daunting. The planet’s ecosystem is a complex system beyond current comprehension. Although we’ve made great strides in understanding its components, we still lack a grasp of the global picture. Weather patterns, biome interactions, large-scale ecological change—our knowledge is deeply limited.

Take global warming, for instance. Contrary to the overwhelming political and media narrative, scientists have yet to conclusively answer two critical questions: Is the Earth truly warming? And if so, is human activity the cause? The debate is ongoing. One could even argue: we know more about the Moon than we do about Earth. And soon, we may know more about Mars, too.

On the implementation side, the environmental challenges are equally formidable. From switching to renewable energy to managing waste, from preserving biodiversity to restoring forests—each task requires intricate technologies, many just as hard as interplanetary travel.

But the greatest obstacle to environmentalism is not technical.

In our era of peace and unprecedented growth—especially in the developing world—nations are racing to catch up with the West. This goal no longer seems unreachable. If trends continue, much of the developing world—China, Brazil, and others—could economically match the West within a few decades.

Yet few consider this sobering truth: if everyone on Earth lived like Americans or Europeans, we would need four and a half Earths’ worth of resources.

Thus, the true goal of environmentalism—preserving Earth’s ecosystems, halting the extinction of species at rates faster than the Cretaceous mass extinction—cannot be achieved by restraint alone. Even if all the goals of the Copenhagen Accord were met, Earth’s fate would remain like that of the Titanic—sinking slowly beneath the ice.

The only real solution would be to stop development altogether. But that is impossible. It’s morally unjust and politically unfeasible to ask one half of the world to live in modern comfort while the other remains in poverty.

Let us consider another possibility: environmental catastrophe caused by non-human factors. Earth’s climate has always fluctuated, though human history is too short to grasp it. Past fluctuations have brought radical changes. A return of the last Ice Age, which ended only 10,000 years ago, would cover continents in snow and collapse modern agriculture—an existential crisis for humanity. Such changes are inevitable in the long run, and may not be far off. In the face of them, today’s environmental methods are hopelessly inadequate.

To survive such upheaval—whether natural or manmade—humanity must go beyond passive protection. We must actively reshape Earth’s environment.

For instance, to counter global warming, ideas have been proposed like installing massive solar evaporation stations on oceans to boost cloud cover, or constructing a 3-million-square-kilometer sunshade at a Lagrange point between Earth and the Sun.

These are not just grand ideas—they are divine in scale, demanding technologies as fantastic as any in science fiction. They are harder than planetary travel.

From an economic standpoint, environmental protection shares much with space development: both require massive funding, with little short-term return. Yet the world spends disproportionately more on the former than the latter.

Take China: in its 12th Five-Year Plan, over 3 trillion yuan was allocated to environmental protection, compared to only 30 billion for space exploration. Other countries follow similar patterns.

And yet, the solar system is bursting with resources. From water to metals to fusion fuel—everything human civilization needs is out there. Earth could one day support 100 billion people, but the entire solar system could support the population of one hundred thousand Earths.

And so, we see this ironic truth: Humanity has abandoned the hundred thousand Earths of space to bet everything on one Earth—investing in environmental protection, an endeavor just as hard, just as risky, as space development.

Like environmentalism, space exploration stimulates technological advancement. Apollo’s success came not from pre-existing technology, but from innovation born of challenge. Nuclear propulsion is feasible with today’s science. Controlled fusion, though still elusive, is theoretically achievable.

Let us not forget: the navigation computer onboard the Apollo spacecraft had only one-thousandth the power of an iPhone 4.

The age of space exploration is not unlike the Age of Discovery, when brave ships crossed unknown oceans in search of new worlds. That era began with Columbus, supported by Queen Isabella of Castile—who, legend says, pawned her jewels to fund his voyage. That small investment became one of the wisest in history. Some say history itself began in 1500, when humanity first understood the world’s full scope.

Now, we stand on the eve of a second Age of Discovery. But unlike Columbus, we can see the new world above us—bright and clear. All we lack is someone to fund the voyage.

Perhaps human civilization, like a human infant, truly cannot leave its cradle without the help of parents.

But from the universe’s perspective, Earth has no parents. Humanity is an orphan.

And we must learn to stand on our own.

---

INTRO: WIKIPEDIA – A View from the Stars

中文版: 一个和十万个地球