Tubby had taught high school math and physics until her inheritance could no longer cover the property tax on the Banqiao house, and she had not learned very much English at the home, so it was rare that she truly understood the talks that she attended in Puda's math department. But every so often the speaker would walk through a proof whose notation was just precise enough for Tubby to follow, and for a few moments she felt clear-headed and young again.

She enjoyed the astrophysics talks as well—more for the visuals than the physics; astronomers were disagreeably loose with notation. Lately, though, the astrophysics talk series had been invaded by astrobiology. These talks usually sent Tubby to the basement of the Puda art museum, whose East Asian collection was excellent.

But there was one that she sat all the way through. The title slide was decorated with the logo of Taisheng's company, which caught Tubby's eye, and she understood enough of the introduction to learn that the speaker, a Dr. Aurélie Ahearn, was filling in for a Dr. Vikas Ramachandran, whose name rang a bell.

She showed images of Jupiter and its moons, of a vast ice plain with vast ice mountains on the horizon, of a spidery construct that seemed to be all drill arms and solar panels. She used words that Tubby remembered having once made Taisheng explain: Telomere extension. Anti-inflammatory. Apoptosis. She showed bright abstract figures measuring quantities Tubby knew she had no hope of understanding.

The questions lasted an hour and a half, long after the department administrators had asked the crowd to clear the room. Tubby stayed for every one, hoping she might hear something more about Dr. Ramachandran. She hustled to the Puda station just in time to watch the train pull away, not to return until she was long overdue for Bio-E.