The sun got into the Halloween spirit a little early this year, producing active spots that look like a jack-o’-lantern leer on October 8. The active spots give off more light and energy than the rest of the sun’s surface.
This visualization shows the sun’s activity in two wavelengths of light, 171 Angstroms and 193 Angstroms. Both wavelengths are in the extreme ultraviolet portion of the electromagnetic spectrum, which is what NASA normally studies.
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.