Katherine Johnson Counts the Stars

Katherine Johnson counted everything.

As a little girl in West Virginia she counted the steps to the road, the plates on the table, the stars she could see from the porch. She loved numbers the way some children love music.

She was so quick that she finished school years early. And when she grew up she went to work at NASA, where people were trying to do something nobody had ever done: send a person up past the sky, all the way around the Earth, and bring them back down safely.

To do that, you need arithmetic. Enormous, careful, exact arithmetic. Where will the Earth be in four hours? How fast must the capsule fall? Where in the whole wide ocean will it land?

Katherine worked it out with a pencil.

When the astronaut John Glenn was about to fly around the Earth, new electronic computers produced the numbers — but Glenn did not quite trust them. Get the girl to check them, he said. He meant Katherine. If she says they're good, I'll go.

She checked. They were good. He went. He came home safely.

So when you look up tonight and see something small and bright moving slowly across the sky, remember: somebody worked out exactly where it should be.

Goodnight, little mathematician.