googleb1fd7cd7ef71feda.html

Πέμπτη 23 Μαΐου 2019

Astronomy Picture of the Day: A Circumhorizontal Arc Over Ohio

See Explanation.  Clicking on the picture will download
 the highest resolution version available.
Why would clouds appear to be different colors? The reason here is that ice crystals in distant cirrus clouds are acting like little floating prisms. Sometimes known as a fire rainbow for its flame-like appearance, a circumhorizon arc lies parallel to the horizon. For a circumhorizontal arc to be visible, the Sunmust be at least 58 degrees high in a sky where cirrus clouds are present. Furthermore, the numerous, flat, hexagonal ice-crystals that compose the cirrus cloud must be aligned horizontally to properly refract sunlight in a collectively similar manner. Therefore, circumhorizontal arcs are quite unusual to see. This circumhorizon display was photographed through a polarized lens above DublinOhio in 2009.
https://apod.nasa.gov/apod/

Δεν υπάρχουν σχόλια: