The Philippine Sea and the thin blue envelope of the atmosphere

Astronauts from the Expedition 48 on the International Space Station captured this image while flying over the Philippine Sea. It shows three-dimensional clouds, the thin blue envelope of the atmosphere, and the blackness of space. The late afternoon sunlight brightens a broad swath of the sea surface on the right side of the image. In the distance, a wide layer of clouds mostly obscures the northern Philippine islands (top right).

Looking toward the Sun to capture an image is a special technique used by astronauts to accentuate the three dimensions of landscapes and cloudscapes through the use of shadows. Two large thunderclouds rise next to one another (lower right). These clouds have long tails, also known as anvils, that stretch nearly 100 kilometers to the south. Anvils form when thunderstorm clouds rise high into the atmosphere and reach a “capping layer” thousands of meters (tens of thousands of feet) above sea level. Capping layers stop the upward growth of a cloud, deflecting air currents horizontally to form anvils.
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Credit: NASA