Sometimes the sun's warm face turns sinister.
This visualization shows the sun's activity in two wavelengths of light, 171 Angstroms and 193 Angstroms.
But wait. Is this benign, or something more disturbing?
Extreme ultraviolet light isn't visible to the naked eye, but it can nevertheless affect human life. When the sun is particularly active, the high-energy photons of extreme UV light can heat the Earth's atmosphere, creating additional drag on mankind's orbiting satellites. Or the photons can break apart atoms and molecules in the atmosphere, creating ions that disrupt radio signals. Luckily for life on Earth, the atmosphere blocks most extreme ultraviolet light from reaching the planet.
That's the sun's skull beneath the face, grinning with the promise of destruction to come.