LEESBURG, Va. — Coronal rain may have a finer grain.
A search for plasma precipitation in the sun’s atmosphere reveals that the rain turns up in unexpected places. That discovery might mean the rain can fall as a fine mist as well as a shower, new data suggest. Ultimately, tracing the movement of this plasma could help solve the mystery of why the solar atmosphere, or corona, is so hot.
The sun has rainfall similar to Earth’s, but with plasma instead of water. When hot plasma moves into a cooler part of the corona, it condenses and falls back toward the solar surface, just as hot air condenses into clouds that form water droplets that rain down on Earth. “The physics is literally the same,” says solar physicist Emily Mason of the Catholic University of America in Washington, D.C., who presented the new observations of coronal rain at the Triennial Earth-Sun Summit on May 22.