Corona (Solar)
Definition
The Sun's outer atmosphere — a halo of million-degree plasma and the birthplace of the solar wind.
In plain language
Visible to the naked eye only during total eclipses, the corona is mysteriously hundreds of times hotter than the Sun's surface. It is so hot that it constantly boils off into space as the solar wind.
The science
The corona is a magnetically structured plasma at 1–3 million K whose heating mechanism remains an active research question. Coronal magnetic topology — streamers, loops, holes — organizes solar wind sources and CME release.
Why it matters for aurora viewing
The corona's structure this week shapes the solar wind at Earth next week — coronal holes and eruptions here are the origin of your forecast.
See this in action on tonight's data.