Why does Earth appear to glow from space?
Today’s Video of the Day from NASA Goddard describes why the Earth is surrounded by bright shades of red, yellow, green, and purple light when the planet is viewed from around 300 miles above its surface.
This phenomenon is known as airglow, which occurs when atoms and molecules in the upper atmosphere produce light to release excess energy. Airglow can also happen when atoms and molecules that have been ionized by sunlight capture a free electron. In either case, a particle of light known as a photon is emitted.
The event is similar to an aurora, except auroras are driven by high-energy particles originating from solar wind, while airglow is driven by everyday solar radiation.
Video Credit: NASA Goddard