Now thats a cool explanation: The sun radiates all visible colors, which is why sunlight appears white. The spectrum of visible light associated with the aurora is much more restricted. The aurora is caused by charged particles in the solar wind colliding with atmospheric atoms and ions. The collisions cause the electrons of the atmospheric atoms to become excited. As the electrons return to their original energy levels, these atoms emit visible light of distinct wavelengths, to create the colors of the display we see. The color of the aurora depends on the wavelength of the light emitted. This is determined by the specific atmospheric gas and its electrical state, and the energy of the particle that hits the atmospheric gas. The atmosphere consists mainly of nitrogen and oxygen, which emit the characteristic colors of their respective line spectra. Atomic oxygen is responsible for the two main colors of green and red. Nitrogen causes blue and deep red hues.
Posted on: Tue, 23 Sep 2014 21:38:56 +0000