The Spheres of Heaven is hard science fiction that’s easy to read. Sheffield doesn’t feel the need to club us over the head with how smart he is or how much he knows.
The story is set in the same multiverse as The Mind Pool. We’re well into the future. Space travel is routine, and we’d even made it to the stars and met some cool aliens: The Stellar Group. Interstellar travel is accomplished through Links – essentially instantaneous travel through constructed gates linking two points. Humanity gets teased with trips to the stars, meets three new species, and then gets cut off from the Interstellar Link system.
It turns out that the Stellar Group has decided humans are violent and has imposed a Quarantine on our solar system. Limited travel in and out by anyone but us. We’re stuck. Then a new Link point is discovered in a nebula called the Geyser Swirl. This Link is not Quarantined, and the Stellar Group needs our help because: 1) They didn’t build it and 2) They’ve sent three expeditions and none have come back.
I enjoyed the story. The ending surprised me and made me say, “ooohhh, that’s brilliant.” Some of the relationships between characters were a little stereotypical, but they worked. The aliens Sheffield created were unique and interesting.
On the Feral Scale, the story came in at a strong 8, and the science came in at a 9. I’m not going to pick nits with a guy with degrees in mathematics and physics who consulted with NASA and served as Chief Scientist for the Earth Satellite Corporation. My biggest gripe was that I wanted more of Sheffield’s thoughts and explanations on how some of his proposed tech would work, and he left a few minor storylines dangling.
I learned some stuff along the way. Lots of info about heavy water and deuterium that ends up being critical to the story in a very ingenious way. I also learned that I need to read more of Sheffield’s work.
Sadly, Sheffield passed away shortly after The Spheres of Heaven was published. It didn’t need a sequel, but I’d certainly have bought one.