July 1, 2009
Volcano, Meet Cloud; Cloud, Volcano
A plume of smoke, ash and steam soars five miles into the sky from an erupting volcano.
The extraordinary image was captured by the crew of the International Space Station 220 miles above a remote Russian island in the North Pacific.
The round hole in the clouds is thought to have been caused by the shockwave of the initial explosion. At the centre lies the billowing mushroom tower of grey and brown ash.
For volcano experts, the most exciting part of the image is the layer of smooth white cloud that caps the plume - a little like a layer of snow on a mushroom.
This cap of condensed air is created from the rapid rising and then cooling of the air directly above the ash column. When moist, warm air rises quickly it creates a cloud.