Friday, April 7, 2017

Plane contrail and sun halo - NATURAL PHENOMENA


What happened to the sky? Several common features of the daytime sky are interacting in a uncommon ways. First, well behind the silhouetted hills, is the typically bright sun. In front of the sun are thin clouds, possibly the home to a layer of hexagonal ice crystals that together are creating the 22 degree halo of light surrounding the sun.

The unusual bent line that crosses the image is a contrail - a type of cloud created by passing airplane. Much of the contrail must actually be further away than the thin cloud because it casts a shadow onto the cloud, giving an unusual three-dimensional quality to the featured image. The featured image was taken in late January in the city of Patras in West Greece.


Image and info via APOD
https://apod.nasa.gov/apod/astropix.html

Image credit & copyright: Alexandros Maragos

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