Like rivers of liquid water, glaciers flow downhill, with tributaries joining to form larger rivers. But where water rushes, ice crawls. Alaska's Susitna Glacier revealed some of its long, grinding journey when NASA's Terra satellite passed overhead on Aug. 27. This satellite image from Terra, released Oct. 20, combines infrared, red, and green wavelengths to form a false-color image. Vegetation is red, and the glacier's surface is marbled with dirt-free blue ice and dirt-coated brown ice. Infusions of relatively clean ice push in from tributaries in the north.

This one-meter ground resolution satellite image shows a portion of Risalpur, located on the Kabul River in the Nowshera District in Pakistan's Northwest Frontier Province about 45 km from Peshawar. The image was taken on Aug. 6, 2009, almost one year before Risalpur experienced historic flooding in late July and early August 2010. This image could be used by humanitarian agencies and first responders to plan post-flooding relief and evacuation activities by comparing "before" imagery to detect changes to the landscape and infrastructure. The IKONOS satellite took this image from 423 miles in space as it moved from north to south over Pakistan at a speed of four miles per second.

This half-meter ground resolution satellite image shows a portion of Risalpur, located on the Kabul River in the Nowshera District in Pakistan's Northwest Frontier Province about 45 km from Peshawar. The image was collected on Aug. 5, 2010 after Risalpur experienced historic flooding and shows the coastline and town covered in mud and water. According to news reports, this area of Pakistan hasn't seen such flooding since 1929. The floods have collectively killed an estimated 1,500 people in Pakistan, affected 4.2 million people and displaced millions from their homes. The GeoEye-1 satellite took this image from 423 miles in space as it moved from north to south over Pakistan at a speed of four miles per second.

Detail of 2009 shot above.

Similar detail from 2010 shot above.

On the left is a satellite image of Nowshera, Pakistan and the surrounding area before it was flooded. The image on the right shows the same area on August 5, after the deluge.

This picture of the curvature of the earth was taken from an altitude of 23.67 miles by a cheap point-and-shoot digital camera connected to a balloon built by amateur photographers Colin Rich and William Ahmanson.