White pinpricks of cloud cast ebony shadows on the Rub' al Khali, or Empty Quarter, near the border between Saudi Arabia and Yemen. The lines of wind-sculpted sand are characteristic of immense sand deserts, or sand seas, and the Rub' al Khali is the largest desert of this type in the world. A highland ridge is just high enough to disturb the flow of the lines. In the center of that interruption lies the Saudi Arabian town of Sharurah.
Earth as Art 3
The Earth as Art Three exhibit provides fresh and inspiring glimpses of different parts of our planet's complex surface.
In the American Southwest, transitions from one ecosystem to another can be dramatic and abrupt. This certainly is true in northern Arizona, USA, where the parched Painted Desert, shown here in a palette of purples, adjoins Sitgreaves National Forest (shades of green), a realm of pine woodlands with abundant wildlife. Within the Painted Desert lie the Hopi Buttes, a field of ancient volcanic cones, seen here as a scattering of dark, circular shapes near the top of the image.
Seen through the "eyes" of a satellite sensor, ribbons of Saharan sand dunes seem to glow in sunset colors. These patterned stripes are part of Erg Chech, a desolate sand sea in southwestern Algeria, Africa, where the prevailing winds create an endlessly shifting collage of large, linear sand dunes. The term "erg" is derived from an Arabic word for a field of sand dunes.
The Caicos Islands (pronounced KAY-kohss) in the northern Caribbean are a popular tourist attraction, renowned for their beautiful beaches, clear waters, scuba diving, and luxury resorts. The islands lie primarily along the northern perimeter of the submerged Caicos Bank (turquoise), a shallow limestone platform formed of sand, algae, and coral reefs covering 6,140 square kilometers (2,370 square miles).
Truly a river of ice, Antarctica's relatively fast-moving Byrd Glacier courses through the Transantarctic Mountains at a rate of 0.8 kilometers (0.5 miles) per year. More than 180 kilometers (112 miles) long, the glacier flows down from the polar plateau (left) to the Ross Ice Shelf (right). Long, sweeping flow lines are crossed in places by much shorter lines, which are deep cracks in the ice called crevasses. The conspicuous red patches indicate areas of exposed rock.
Like sweeping brushstrokes of pink and green, the Belcher Islands meander across the deep blue of Canada's Hudson Bay. The islands' only inhabitants live in the small town of Sanikiluaq, near the upper end of the middle island. Despite the green hues in this image, these rocky islands are too cold to sustain more than a smattering of low-growing vegetation.
San Juan, Argentina, nestles in a fertile valley flanked by arid mountains. Croplands and vineyards (green) abut the metropolitan area on the San Juan River. The white "teardrop" (lower left) is an ancient lakebed called Barreal Blanco. It is one of the best places in the world for carrovelismo, or landsailing, thanks to the steady winds that sweep across this flat, unobstructed expanse of hard-packed sediment.
The prominent crimson streak in the center of this image represents the remains of an extensive lava and mud flow. Its source is the currently dormant Anyuyskiy Volcano orange circular shape at the right end of the streak) in northeastern Russia. Remote and largely inaccessible, the region is a rugged collection of towering volcanic peaks, steep valleys, and wild, snow-fed rivers and streams.
This abstract in browns and grays from central Algeria shows that some parts of Africa's Sahara Desert contain much more than dunes of wind-blown sand. Barren ridges and fragmented mountains (lower right) border a vast expanse of arid plains etched with a complex system of dry streambeds. The streambeds contain water for brief periods following rare, intense rains that often cause flash floods.
What look like pale yellow paint streaks slashing through a mosaic of mottled colors are ridges of wind-blown sand that make up Erg Iguidi, an area of ever-shifting sand dunes extending from Algeria into Mauritania in northwestern Africa. Erg Iguidi is one of several Saharan ergs, or sand seas, where individual dunes often surpass 500 meters-nearly a third of a mile-in both width and height.