skyeye
A Triangular Shadow of a Large Volcano

Why does the shadow of this volcano look like a triangle? The Mount Teide
volcano itself does not have the strictly pyramidal shape that its geometric
shadow might suggest. The triangle shadow phenomena is not unique to the
Mt. Teide, though, and is commonly seen from the tops of other large mountains
and volcanoes. A key reason for the strange dark shape is that the observer is
looking down the long corridor of a sunset (or sunrise) shadow that extends to
the horizon. Even if the huge volcano was a perfect cube and the resulting shadow
was a long rectangular box, that box would appear to taper off at its top as its
shadow extended far into the distance, just as parallel train tracks do. The above
spectacular image shows Pico Viejo crater in the foreground, located on Tenerife
in the Canary Islands of Spain. The nearly full moon is seen nearby shortly after
its total lunar eclipse last month.