Out here the reactor's whole output is spent on arithmetic, and the only thing you can see of the thinking is the heat.
An artistic imagining, rendered procedurally as a three block woodcut, of a listening array on an Oort cloud body that spends its entire power budget on arithmetic: one small reactor feeds a branching cable to fifty dishes, and everything they hear is folded together in the long bank on the right, whose only visible product is heat. The load is real even if the hardware is not: correlating an N element radio array means computing N(N-1)/2 baseline products continuously, so the processing and its cooling scale with the square of the array and are among the largest electrical loads at a working radio observatory, and at roughly 10,000 AU sunlight is about a hundred million times weaker than at Earth, so an outpost that far out has to carry its own reactor.Image: poweringspace.com. Artistic imagining.