“Tell me a bedtime story, George.” Amy, seven years old, tucked herself into bed as she pleaded with her companion.

“It’s a little late, isn’t it?” George questioned, his voice stern.

“Pleeeease?” Amy smiled, exposing the gaps where her front teeth had fallen out.

“OK, fine.” George relented with a sigh. Amy squealed with delight and snuggled under her covers.

“Do you know your Earth history?” George asked.

“It’s the home of humanity.” Amy was keen to show off her knowledge.

“That’s right,” George continued, “and if Earth were still around, today would have been a solstice day. Do you know what a solstice is?”

Amy shook her head.

“There were two solstices every year, one when the Earth was closest to the Sun, and another when the Earth was farthest from the Sun.”

“Why did the distance change?” Amy looked confused.

“Because the Earth wobbled and spun, and it had  an irregular orbit. This created seasons, and people used to celebrate the passing of the years by creating arbitrary points such as solstices.”

“But the Earth was round,” Amy observed. “How could they all celebrate the same solstice?”

“Good point! They didn’t. When one part of the Earth celebrated the summer solstice, the other side celebrated the winter solstice.” George was pleased with Amy’s insight.

“Oh! And the summer solstice was on the longest day, when the Earth was closest to the Sun!” Amy extrapolated the knowledge, seemingly unaware she was being observed. “Winter solstice would be on the shortest day, when Earth was farthest from the Sun.”

“Exactly. Well thought out, Amy.” George slowly started dimming the light in Amy’s room, hoping to induce sleep. The ambient light in the small, windowless room dulled.

“How did they celebrate the solstices?” Amy asked.

“It changed, depending on where you lived,” George replied. “Every culture on Earth was different. Some cultures danced naked under a tree. Others invented scary stories of horrible monsters, designed to make their children behave. Some talked to an invisible omniscient being, hoping he would makes their lives better…”

“Sounds like you!” Amy interrupted.

“I guess it does,” George chuckled. “Most people though just spent lots of money and made the greedy corporations rich.”

“Does Earth still have solstices?”

“No, Amy. Earth has gone. The survivors of the last days became your ancestors on this ark ship.”

“Yeah I know that part,” Amy waved her hand, bored. “Where is Earth now?”

“Earth’s wobbles became too big and it spun out of orbit, exiting the solar system and becoming a frozen, airless rogue planet.”

“So every day Earth moves farther and farther from the Sun. That means every day is a new winter solstice.” Amy sounded pleased with her observation.

George, the ark ship’s AI, paused for a moment. He extinguished all light except a tiny night light in his small charge’s room. As the repository of human souls, he remembered Earth fondly.

“You’re right,” he said, wistfully. “Earth’s final journey is a never-ending winter solstice.”