Bisesa hadn’t entered hers until 2050, eight years after the storm.

“I can talk you through the medical advances since your immersion,” Thales said. “For example it now appears that your cells’

propensity for hydrogen sulphide is a relic of a very early stage in the evolution of life on Earth, when aerobic cells still shared the world with methanogens.”

“That sounds oddly poetic.”

Thales said gently, “There is the motivational aspect as well.”

She felt uncomfortable. “What motivational aspect?…”

She had had reasons to flee into the tanks. Myra, her twenty-one-year-old daughter, had married against Bisesa’s advice, and pledged herself to a life off the Earth entirely. And Bisesa had wanted to escape the conspiracy-theory notoriety that had accrued about her because of her peculiar role in the sunstorm crisis, even though much of what had gone on in those days, even the true cause of the sunstorm, was supposed to have been classified.

“Anyhow,” she said, “going into a Hibernaculum was a public service. So I was told when I signed over my money. My trust fund went to advance the understanding of techniques that will one day be used in everything from transplant organ preservation to crew-ing centuries-long starship flights. And in a world struggling to recover after the storm, I had a much lower economic footprint frozen in a tank—”

“Bisesa, there is a growing body of opinion that Hibernaculum sleeping is in fact a sort of sublimated suicide.”

That took her aback. Aristotle would have been more subtle, she thought. “Thales,” she said firmly. “When I need to speak to someone about this, it will be my daughter.”

“Of course, Bisesa. Is there anything else you need?”

She hesitated. “How old am I?”

“Ah. Good question. You are a curiosity, Bisesa.”