Glaciers from space
“ To a geologist, glaciers are among the most exciting features on Earth. Though they seem to creep along at impossibly slow speeds, in geologic time glaciers are relatively fast, powerful landscape artists that can carve out valleys and fjords in just a few thousand years. Glaciers also provide an environmental record by trapping air bubbles in ice that reveal atmospheric conditions in the past. And because they are very sensitive to climate, growing and advancing when it's cold and shrinking and retreating when its warm, they can be used as proxies for regional temperatures. ”