- The photosphere lie the tenuous chromosphere and the corona (crown), which make up the thin solar atmosphere. This is where we see features such as sunspots and solar flares.
- Visible light from these top regions is usually too weak to be seen against the brighter photosphere, but during total solar eclipses, when the moon covers the photosphere, the chromosphere looks like a red rim around the sun, while the corona forms a beautiful white crown with plasma streamers narrowing outward, forming shapes that look like flower petals.
- Strangely, the temperature in the sun's atmosphere increases with altitude, reaching as high as 3.5 million degrees Fahrenheit (2 million degrees Celsius). The source of coronal heating has been a scientific mystery for more than 50 years.