The Three-Body Problem

“And then three flying stars froze simultaneously. The people of Civilization 191 stood on the ground, gazing up helplessly at the three frozen flying stars, at the three suns falling directly toward their world. A few days later, one of the suns moved to a distance where its outer gaseous layer became visible. In the middle of a tranquil night, the star suddenly turned into a blazing sun. Separated by intervals of thirty hours or so, the other two suns also appeared in quick succession. This was not a normal kind of tri-solar day. By the time the last flying star turned into a sun, the first sun had already swept past the planet at extremely close range. Right after that, the other two suns swept past Trisolaris at even closer ranges, well within the planet’s Roche limit31, such that the tidal forces imposed on Trisolaris by the three suns exceeded the force of the planet’s gravitational self-attraction. The first sun shook the deepest geological structure of the planet; the second sun tore open a great rift in the planet that went straight to the core; and the third sun ripped the planet into two pieces.”

The secretary general pointed at the giant moon overhead. “That’s the smaller piece. There are still ruins from Civilization 191 on it, but it’s a lifeless world. It was the most terrible disaster in the entire history of Trisolaris. After the planet was torn apart, the two irregularly shaped pieces each returned to spherical form under self-gravitation. The dense, searing planetary core material gushed to the surface, and the oceans boiled over the lava. The continents drifted over the magma like icebergs. As they collided, the ground became as soft as the ocean. Massive mountain ranges tens of thousands of meters high rose in an hour and disappeared just as quickly.

“For a while, the two ripped-apart pieces were still connected by streams of molten lava that coalesced into a space-spanning river. Then the lava cooled and turned into rings around the planets, but because of perturbations from the planets, the rings were unstable. The rocks that formed them fell back to the surface in a rain of giant stones that lasted several centuries.… Can you imagine what kind of hell that was? The ecological destruction caused by this catastrophe was the most severe in all of history. All life on the companion planet went extinct, and the mother planet almost became a lifeless waste as well. But in the end, the seeds of life managed to germinate here, and as the geology of the mother planet settled down, evolution began its tottering steps in new oceans and on new continents, until civilization reappeared for the one hundred and ninety-second time. The entire process took ninety million years.

“Trisolaris’s place in the universe is even more grim than we had imagined. What will happen the next time frozen flying stars occur? Very likely, our planet will not just skim past the edge of the sun, but will plunge into the fiery sea of the sun itself. Given enough time, this possibility will become certainty.

“This was originally just a frightening speculation, but a recent astronomical discovery has caused us to lose all hope for the fate of Trisolaris. The researchers had intended to recover the history of the formation of the stars and the planets based on signs in this stellar system. Instead, they discovered that, in the distant past, the Trisolaran stellar system had twelve planets. Yet, now only this one remains.

“There is only one explanation: The other eleven planets have all been consumed by the three suns! Our world is nothing more than the sole survivor of a Great Hunt. The fact that civilization has been reincarnated a hundred and ninety-two times is only a kind of luck. Also, after further study, we discovered the phenomenon of ‘breathing’ by the three stars.”

“The stars breathe?”

“It’s only a metaphor. You discovered the gaseous outer layer of the suns, but you didn’t know that this gaseous layer expands and contracts over cycles lasting eons, like breathing. When the gaseous layer expands, its thickness can grow by more than a dozen times. This greatly increases the diameter of the sun, like a giant mitt that can catch planets more easily. When a planet passes by a sun at close range, it will enter the sun’s gaseous layer. Friction will cause it to lose speed, and finally, like a meteor, it will fall into the blazing sea of the sun, dragging a long, fiery tail.

“The study results show that in the long history of the Trisolaran stellar system, every time the suns’ gaseous layers expanded, one or two planets were consumed. The other eleven planets all fell into a fiery sea during times when the gaseous layers were at their greatest. Right now, the gaseous layers of the three suns are in a contracted stage—otherwise our planet would have already fallen into one of them the last time they skimmed past. But scholars predict that the next expansion will occur in one thousand years.”