The smart fields of the High Archon and the senator darkened. “Do you find this work distressing?” asked the fleet commander.

“Another species gone, like dew in the sun.”

“Think of the Battle of the Second Arm, Your Excellency—more than two thousand supernovas detonated, one hundred and twenty thousand planets with life vaporized. We do not have the luxury to be sentimental.”

The senator ignored the fleet commander. He addressed the High Archon directly. “Random planetary spot checks are unreliable. There may be signs of civilization elsewhere on a planet’s surface. We should implement area scans, as well.”

The High Archon said, “I have discussed that possibility with the Senate. We must destroy hundreds of millions of stars in the isolation belt. We estimate the belt contains ten million planetary systems and fifty million planets. Our time is limited; we will not be able to conduct a full area scan on each planet. All we can feasibly do is widen the detection beam to scan larger random samples … and pray the civilizations that might exist here have spread uniformly across their planets’ surfaces.”

*

“Next, we’ll learn Newton’s second law.”

He spoke as quickly as he could, to teach the children as much as possible in the short time he had left.

“An object’s acceleration is directly proportional to the force acting on it, and inversely proportional to its mass. To understand that, you need to know what acceleration is. Acceleration is the rate at which an object’s speed changes over time. It’s different from speed—an object that’s moving fast isn’t necessarily accelerating rapidly, and a quickly accelerating object may not be moving fast. For example, say there’s an object moving at 110 meters per second. Two seconds later, it is moving at 120 meters per second. Its acceleration is 120 minus 110, divided by two … that’s five meters per second—no, five meters per second squared. Another object is moving at ten meters per second, but two seconds later, it’s moving at thirty meters per second. Its acceleration is thirty minus ten, divided by two—ten meters per second squared. The second object may not be as fast as the first, but its acceleration is greater! I mentioned squares—a square is just a number multiplied by itself …”

He was surprised that his thinking was suddenly so clear. He knew what this meant: If life is a candle, his had burned to its base, and its wick had fallen and ignited the last bit of wax there, with a flame ten times brighter than before. His pain was gone and his body no longer felt heavy; in fact, he was barely aware of his body at all. The life he had left seemed to be in his brain, which worked furiously to convey all its knowledge to the children gathered around him. Language was a bottleneck—he knew he didn’t have enough time. He fantasized that the knowledge he had spent his life accumulating—not much, but dear to him—was lodged in his brain like small pearls, and that as he spoke, a crystal ax chopped the pearls out of his brain onto the floor, where the children scrambled to gather them like sweets at New Year’s. It was a happy fantasy.