Colorful Noctilucent Clouds in the Sky STS131
After the space shuttle Discovery lauched out of Kennedy Space Center this morning, the clouds left behind by the orbiter began reflecting extremely beautiful colors. In fact, if you look at the rocks in the immediate foreground, you will see they are illuminated by the very light coming from the clouds above. This was absolutely spectacular... may have to make a large print of this one!
UPDATE: Noctilucent cloud
A cloud of unknown composition which occurs at great heights and high altitudes; photometric measurements have located such clouds between 45 and 54 miles (75 and 90 kilometers); they resemble thin cirrus, but usually with a bluish or silverish color, although sometimes orange to red, standing out against a dark night sky.