Five Hundred Light Years

Camila let Polly stand on the back of her chair. The control room was dark. It was lit only by red lamps to keep eyes ready for darkness.

The target was a star called HD 189733. It is 63 light years from Earth. It has one planet that we know about. The planet is the size of Jupiter. It is very close to the star.

Tonight, the planet was going to pass in front of the star. The telescope would measure the light through the planet's atmosphere. This is called transmission spectroscopy.

The light from the star is normal light. After it passes through the planet's atmosphere, parts of it are missing. The missing parts tell us what the atmosphere is made of.

Camila and her team had already found water and sodium in this atmosphere. Tonight, they were looking for carbon monoxide.

"Why does it matter?" Polly asked.

"This planet is too hot for life," Camila said. "It is 1,500 degrees. But learning about its atmosphere helps us learn about cooler planets where life might be."

A small green line on her screen began to drop. The transit had started.

"There," Camila said. "The planet is in front of the star."

The light from the star had taken 63 years to get here. 63 years ago, humans had not yet landed on the Moon.