Friday, 25 May, 2012

The Skogafoss is one of the biggest waterfalls in Iceland, and is especially beautiful in this stunning image under the aurora borealis. The Northern Lights are shining against a great sea of stars, including the constellation Ursa major, or Great Bear, home to the asterism — a recognizable cluster of stars — the Big Dipper. [...]

The colors of the sunset result from a phenomenon called scattering, says Steven Ackerman, professor of meteorology at UW-Madison. Molecules and small particles in the atmosphere change the direction of light rays, causing them to scatter. Scattering affects the color of light coming from the sky, but the details are determined by the wavelength of [...]