I carried the envelope home and showed my mother, and she insisted we wait until Mr. Okonkwo was well. Two weeks later, he was walking again, with a cane, and he invited us to his house for tea. He sat us down in the front room and asked me to open it. Inside was a letter, a photograph of a night sky, and a certificate with a gold seal.

The letter explained that Mr. Okonkwo had been an astronomer for forty years. In 1987, he had discovered a small comet, which an international committee had agreed to name after its discoverer. But he had asked them to keep the name in reserve, because he had never found the right person. He wanted to name it for someone who looked after others without being asked. The certificate was an official registration, and I read the name on it three times.

It said, “Comet Santos.” I did not understand at first. My mother covered her mouth. Mr. Okonkwo smiled and said that the comet would return to the sky in the year 2060, when I would be forty-six years old. He said he would not be there, but he hoped I would stand outside with my own children and look up. He also gave me his old brass telescope, which weighs more than my little sister.

I still deliver newspapers every morning, and I still check on Mr. Okonkwo at number nine. He is ninety now, and on clear Saturday nights, he teaches me the constellations from his porch. Mari asks to hold the telescope, and I always let her. The certificate hangs above my bed. Sometimes before I sleep, I look at it and think about something small that turned out to be big, like a key under a frog.