The probe named for Eugene Parker (in 1977) is about to get an up close portrait of the sun. “That says you are dealing with a gas-a hydrodynamic flow of gas.” In other words, the sun was emitting not just electromagnetic radiation but low-density gales of particles.

There is some slight motion, but it is not flowing at any noticeable rate.” But when you study this radiation much farther out, “it is busy blowing the comet tails away,” he says. Parker, now 90, says that during his research he discovered that “the corona is mostly static near the sun. He read some of the papers on solar particles and started connecting the dots. In the early 1950s, Eugene Parker, an astrophysicist at the University of Chicago, wanted to study why the sun’s atmosphere is so hot. Not until the 20th century did astronomers propose that along with light, the sun emits a steady stream of particles, which pushes a comet’s tail around. Perhaps one day, he speculated with grand vision, voyagers could use this solar power as propulsion on trips across the stars: “Provide ships or sails adapted to the heavenly breezes, and there will be some who will brave even that void.” German astronomer Johannes Kepler was among its many observers, and he wrote to Galileo Galilei wondering whether it was sunlight that caused the comet’s tail to smear across the sky. In 1607, an apparition appeared at night: a comet that would eventually be named after Edmond Halley, the astronomer who predicted its 75-year orbit. The Parker Solar Probe will sample this layer of the sun directly, and for the first time we will be able to retrieve information about the realm that connects Earth and our star.Ĭomet tails were the first evidence that the sun was more than a static ball in the sky. From Earth, we can’t see the corona, unless we watch during a total solar eclipse. Solar wind from the corona drifts outward, crossing 93 million miles of space to create the aurora in Earth’s magnetosphere. We know that the sun’s atmosphere is much hotter than its outer plasma layer, a fact that seems to defy thermodynamics. What happens here, in the sun’s atmosphere stretching out millions of miles, affects this planet and every other place in our neighborhood, but its dynamics remain mysterious. Instead, the probe will fly directly into the only region of the solar system so far unexplored by spacecraft: the corona. That would be too dangerous-and impossible, because the sun is a roiling furnace of plasma, a state of matter unable to form what could be considered a surface.

It will ultimately settle into an elliptical orbit that, at perihelion, comes within 3.9 million miles of the sun’s visible surface, more than seven times closer than any spacecraft has dared venture. At its top speed, the spacecraft will scream through space at 430,000 mph, fast enough to travel from New York to Los Angeles in 25 seconds.ĭuring seven years of carefully choreographed swoops, it will draw closer to the sun, like a matador dancing inward toward a glowering bull. A Delta IV Heavy rocket with an added upper stage will boost NASA’s Parker Solar Probe away from Earth and, whipped by Venus’ gravity, it will soon become the fastest spacecraft ever flown. In July, humanity will dispatch its first emissary to our star.

Sun corona facts