It was 1958. Sputnik had launched only a year earlier, the first human-made object to circle the planet. But the spacecraft had no instruments to measure anything in space.

The study of what was up there was largely limited to what scientists could observe from the ground. It certainly looked like the vast expanses between planets were empty. And that is what most scientists believed.

But not Eugene Parker, then a 31-year-old, no-name professor at the University of Chicago. In a paper published in the Astrophysical Journal, Parker described how charged particles streamed continuously from the sun.

Almost no one believed him.

“The prevailing view among some people was that space was absolutely clean, nothing in it, total vacuum,” Parker recalled during an interview at his home.

Four years later, Parker was vindicated when Mariner 2, a NASA spacecraft en route to Venus, measured energetic particles streaming through interplanetary space — exactly what Parker had predicted. Scientists now call that stream of particles the solar wind.

Sixty years after Parker’s paper, NASA is about to launch a spacecraft that is to dive into outer wisps of the sun’s atmosphere and gather information about how our star generates that solar wind. It is the Parker Solar Probe, named after Parker, now 91 years old. It is the first time that NASA has named a mission for a living person.