This is a hard science fiction novella published by Tor.com on April 16, 2019. It runs 216 pages. Egan is an Australian mathematician and programmer who has won multiple awards, including the John W. Campbell Memorial Award, the Hugo Award, and the Locus Award. This review contains spoilers.

Matt is the designer and operator of a self-sustaining aquaculture rig called the Mandjet. When the twin back hole Taraxippus passes the solar system, it pulls the Earth into a different orbit, increasing summer heat in the Southern hemisphere to life-threatening levels. Matt tries to get his family in Australia to join him on the rig, but they refuse. As the perihelion summer arrives, refugee populations migrate north and south, looking for livable temperatures. Matt finds Mandjet has become part of a flotilla aiming to settle in Antarctica. Meanwhile conditions are deteriorating in Australia. Can Matt rescue his family? Fight off pirates to get them to safety?

In case you’re wondering, Taraxippus is an ancient demon that frightens horses, and the black hole’s passing is a novel approach to climate change. The presentation here skips along in a shorthand version of what I’m sure could have been a lengthy novel. Egan spends some time on the black hole and how its passing might affect the solar system. He’s also clearly interested in the details of the aquaculture rig. After the climate change effects are clear, he turns to how this might affect his characters. People react in different ways, some clinging to their old concerns, with others realizing that life has changed forever. In classic hard SF methodology, Egan hits us with an emotional wallop at the end.

On the not so positive side, this was intellectually interesting, but didn’t quite click for me. There was a reasonable plot, but not much of an action line to develop it. The characters didn’t seem deep, and Egan seriously soft-pedals the kind of violence I’d expect from the sudden pressure on half the Earth’s population. There doesn’t seem to be much response from either local or world government to address the crisis—no intervention from the Northern hemisphere, for example, that would have come out of this disaster in reasonable condition, and nothing about the politics it should generate. Plus, this would have been way more enjoyable if Egan had scattered the kind of emotion we get at the end throughout the piece.

Three and a half stars.