On the name.

My hometown is on China's southeastern coast, where every summer and autumn the typhoons arrive on schedule. In those years my study was a wooden shed built on the rooftop of a three-story building in an old residential compound. I read there, slept there, ate there — it was the whole of my childhood world. Then, in 1992, a typhoon tore its roof off and brought the whole hut crashing down. The image has never left me.

I couldn't understand it then: with all our technology, why were we helpless against a typhoon? It took me years to see the answer. However fast human capability grows, it has not yet touched nature's scale. We can raise towers; we cannot stop one storm. And that gap in force is precisely the greatest obstacle between humanity and becoming a multi-planetary species. Could human power keep climbing at this pace? Could it ever reach nature's scale — even the scale of planets? The question has circled in my mind ever since.

In college, I read about the butterfly effect in a magazine: a butterfly flapping its wings in the Amazon, it said, could set off a typhoon in Asia. My first reaction was not awe at the beauty of chaos. It was an almost instinctive thought: if we could catch that precise butterfly, couldn't we smother — before it was ever born — the very typhoon that would one day flatten my study?

Of course, in Earth's chaotic atmosphere, no one can catch that butterfly. But it left me with a decisive insight: humanity's advantage was never raw force. It is thinking, analysis, and strategy — the art of winning a lopsided game through positioning. The characters that stayed with me from Liu Cixin's Three-Body trilogy are exactly these: Zhang Beihai, who concealed his true plan for decades, and Luo Ji, the Swordholder who held an entire civilization at bay with a single strategic idea.

Over the past decade, Mars settlement and the multi-planetary question became the focus of my work. Yet the deeper I studied, the more I felt a clear-eyed helplessness — especially after reading A City on Mars: measured against what truly settling another planet requires, humanity's present technical inventory leaves a gulf that is hard to overstate. The feeling was familiar. It was the child's fantasy of standing up to the typhoon head-on.

If the typhoon cannot be fought head-on, return to the butterfly — catch it earlier, and dissolve the typhoon before it forms. And this time, space deals us favorable terms. In Earth's atmosphere, billions of variables tangle together and no one can trace the butterfly. In space, celestial bodies obey deterministic mechanics — incomparably more computable than the path from a wing-flap to a typhoon. And computation happens to be the human capability growing fastest of all, on the curve of Moore's law. An advantage like that should not be overlooked.

So who is the butterfly of the universe? Put differently: where is the entry point through which humanity becomes a multi-planetary species?

When I went deep into the world of asteroids, I knew I had found the answer. Asteroids are that cosmic butterfly: small enough to sit within the reach of present human capability, large enough — through the accumulation of time — to reshape the fate of planets. Impacts wrote this world's habitability: an ancient giant impact made the Moon; a single asteroid ended the age of dinosaurs. Planetary-scale energy already lies stored in the orbital dynamics of small bodies. Our task is only to intervene at the right moment — to catch these butterflies, and turn a force that was once purely destructive to human use.

From that moment on, I have been devoted to one thing: how asteroids can become the cosmic butterflies that serve humankind.

Perhaps, beyond the laws of physics, the evolution of ideas obeys a butterfly effect of its own. As I set these words down, a butterfly of the mind flapped her wings, once. Given time, she may help push humanity off this planet — and truly into the deep solar system.

— Kailong Cai