By Maro · Egypt Planners · Last updated: June 2026 · Eclipse data: NASA
What Is the Solar Corona?
The corona is the Sun's outermost atmospheric layer -- an ethereal halo of superheated plasma extending millions of kilometers into space. Normally invisible against the Sun's brilliant surface, it reveals itself during total solar eclipses as a pearly white glow surrounding the black disk of the Moon.
Despite being farther from the Sun's core, the corona is paradoxically much hotter than the solar surface -- reaching temperatures of 1-3 million degrees Celsius compared to the surface's 5,500°C. This "coronal heating problem" remains one of solar physics' greatest unsolved mysteries.