Atomic rockets, space colonies, and x-ray binaries

There are at least three award-winning science fiction writers who do or did research in astrophysics. Gregory Benford studies space plasma at the department of physics and astronomy at the University of California, Irvine. David Brin earned a PhD in physics at the University of California, San Diego; Hannes Alfvén was his thesis adviser. Alastair Reynolds was, until 2004, an x-ray astronomer at the European Space Research and Technology Centre in Noordwijk, the Netherlands.

It seems natural for literary physicists to write speculative fiction. The laws of nature that they study and elucidate describe not only what does happen but also what could happen. Cheap, near limitless energy from nuclear fusion is not obviously ruled out by known physics, nor are humanoid robots that could pass a Turing test or memory sticks that could plug into our brains to upload or download information. Physicists also know how physical laws might be plausibly bent, or plausibly extended, to account for uncanny phenomena and astounding technologies.

Other physicists, motivated less by literature, exercise their knowledge and imaginations to write what might be called speculative fact. To illustrate what I mean, consider the late nuclear physicist Leslie Shepherd .

Born in South Wales in 1918, Shepherd led the team that developed Britain’s high-temperature gas-cooled nuclear reactor in the 1950s and 1960s. Throughout his long career, he maintained an interest in the topic that had captured his imagination as a young boy: space travel. In two papers, “The atomic rocket” (1949, written with Rolls Royce engineer A. V. Cleaver) and “Interstellar flight” (1952), Shepherd worked out the physics of practical space travel. Achieving near light-speed travel, he proposed, would require engines powered by the annihilation of matter and antimatter.

Another writer of speculative fact was Gerard O’Neill. Nine years younger than Shepherd, O’Neill was born in Brooklyn. In 1956 he wrote a paper that outlined the storage ring, a device that traps a beam of high-energy particles from an accelerator and holds it until it can be released to smash into a second beam.

Besides particle physics, O’Neill’s other calling was the colonization of space, which was the title of an article he wrote for the September 1974 issue of Physics Today. Raw materials from the Moon and asteroids could be mined and processed to build vast cylindrical habitats whose rotation would mimic gravity. Colonists would live on the inner surfaces.

Most physicists do not devise future technologies, fictional or not. However, many of the most successful physicists have been led by their imaginations, ambitions, or both to new discoveries. In 1928 Paul Dirac incorporated special relativity into the quantum mechanics of the electron. His equations predicted negative energy states that could not be brushed under a theoretical carpet, even though the states would be manifest in two weird phenomena that had not been observed: Either electrons spontaneously switch charge from negative to positive or positively charged electrons exist.

Dirac did not ignore the problem of negative states. Three years later he published a paper in which he took the bold step of predicting the existence of antimatter. Here’s a quote from the introduction:

When I look back on my own, pre- Physics Today career as an astrophysicist, I note with regret that my most imaginative paper was the first one, written while I was still a graduate student. Its subject, Hercules X-1, is binary system that consists of an x-ray-emitting neutron star and a normal star. In “Observations of three high-state eclipse egresses of Hercules X-1,” my coauthors and I sought to explain why the atmosphere on one side of the normal star was puffed up. The combination of radiation pressure from the x rays and the Coriolis force arising from the stars’ orbit was my answer.

So whatever stage you’ve reached in your career, I urge you to emulate the likes of Brin, Shepherd, and Dirac and let your imagination wander. You might not win a Hugo Award for science fiction or a Nobel Prize for physics, but you could create something original that you’re proud of.