Scientists uncover what drives coronal rain on the Sun

Coronal rain on the Sun (Image: NASA's Goddard Space Flight Center)

Astronomers have figured out what causes solar coronal rain. It turns out that fast shifts in the amounts of elements like iron, silicon and magnesium cause the plasma in the Sun's corona to cool off and bunch up, forming streams of coronal rain.

Who Figured Out the Solar Rain Mystery?

Scientists at the University of Hawai‘i’s Institute for Astronomy have revealed what causes the Sun’s coronal rain. This plasma falling from the corona has confused astronomers for years. The team's work explains how shifts in elements causes this amazing sight.

When Was This Found?

This research is a recent discovery, based on years of observing the Sun. Past ideas assumed the corona always had the same elements, which didn’t explain the activity seen in coronal rain.

Where Does Solar Rain Happen?

Coronal rain forms high up in the Sun's corona, which is its outer atmosphere, and falls down along magnetic field lines. Special telescopes that see extreme ultraviolet light can spot these events.

What Makes It Rain?

The team learned that fast changes in elements, like iron, silicon and magnesium, affect how energy is lost as radiation. When these elements change, plasma cools and clumps, making droplets that rain along magnetic loops. This goes against old ideas that the corona is the same all over.

Main Point of This Discovery

The simulations showed that changing elements cause clumping, which makes the plasma streams we see as coronal rain. This lets scientists guess when and where these events might happen.

This find shows that the Sun is complicated and always changing. It gives us a clearer picture of how shifts in elements affect the Sun and how energy is spread. It also opens up new ways to study space weather.