When Chris Moseley, an instructor at the U.S. Military Academy at West Point, decided to teach a "special topics" course on general relativity, he opted for an unusual supplementary textbook: Larry Niven's 1973 novel *Protector*, which vividly depicts a battle between spaceships moving at relativistic speeds.

Moseley writes in a paper that he had expected that at most one or two cadets would want to study general relativity; he assumed there would be little interest in the subject since it didn't have any obvious relevance to an Army career and because it had a reputation for being so difficult. But most of the cadets had advanced placement in mathematics by the time they arrived at West Point, and the course turned out to be far more popular than Moseley had expected

Eager to find a challenging, innovative problem for the cadets to solve, Moseley hit upon the idea of using Niven's book, *Protector *— which, during the second half, focuses on a relativistic space "dogfight" that takes place over years (and is often cited as one of the most realistic depictions of a space battle in science fiction literature).

As Moseley notes, at one point the battle involves a close approach to a neutron star as part of a gravitational perturbation maneuver:

Since the neutron star in the story is described as slowly rotating, the environment near the star could be modeled with a Schwarzschild metric. For their group project, the cadets were required to extend their knowledge of special and general relativity to compute the acceleration, deceleration and orbital elements required to execute the perturbation maneuver while remaining consistent with Mr. Niven's story.

The cadets' analysis was so good that Moseley emailed a copy to Niven who replied:

"Never underestimate students' interests," Moseley concluded, "regardless of their intended career path."