Channeling Earth: Rivers Seen From Space by Mostafa18


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									Channeling Earth: Rivers Seen From Space

Rivers connect Earth’s mountains and lakes to its oceans, creating lifelines that
provide water, food, transportation and recreation along the way. Some rivers, like the
Nile, bring life to barren landscapes that would otherwise be uninhabitable. Others,
like the Mississippi, defy our best efforts to tame them.
Rivers carve their way across the continents, some becoming ever more entrenched
while others meander freely across the surface. The myriad paths they carve make
patterns that are best seen from above.
In this gallery, we’ve collected images from satellites and astronauts of some of the
longest, twistiest, most beautiful and interesting rivers in the world.
Click on any image in this gallery for a high-resolution version.

Rio Negro, Argentina
The Rio Negro in Argentina is a beautiful example of how mobile some rivers are.
This is one of the most meandering rivers in South America. In the image above,
taken by astronauts aboard the International Space Station on January 4, the river has
left scars all across the floodplain as it moved and carved new channels. Some of the
old river channels still have water in them and are known as oxbow lakes.

Image: NASA

Mississippi River
Over the past 10,000 years, the Mississippi River has wandered along 200 miles of
coastline, switching to a new outlet into the Gulf of Mexico every thousand years or
so. Left alone, it would continue to move. Holding it in place is one of the Army
Corps of Engineers’ most impressive feats. The Mississippi is the biggest river in the
United States, stretching 2,320 miles.
The image above, taken by the Landsat 7 satellite in 2001, shows the Birdfoot Delta,
which the river has inhabited for around 600 years and measures more than 31 miles
across. The image below, taken by GeoEye’s Ikonos satellite, shows the river after it
broke at least two levees in June 2008, flooding the city of Gulfport, Illinois.

Images: 1) USGS/NASA. 2) GeoEye.
Ganges River, India
The false color image of the Ganges River Delta was taken in 2000 by the Landsat 7
satellite. Bare, sandy soil appears white in the image, and the swamp forests of the
region, home to the Royal Bengal Tiger, show up as green. The 1,560-mile-long river
originates in the Himalayas and flows across the Uttarakhand state of India to the Bay
of Bengal.
San Juan River, Colorado
The San Juan River runs 400 miles from Colorado through New Mexico and into
Utah where it flows into the Colorado River. This image is of Utah’s Gooseneck State
Park, named for the crazy switchbacks the river takes here. In certain places, it has
packed 5 miles of river into a 1 mile stretch of land. This part of the San Juan is a
popular river rafting destination. Another stretch in New Mexico is famous among fly
Image: GeoEye
Nile River, Egypt
The Nile River carves a fertile scar through this arid part of Egypt, providing a lifeline
in an otherwise barren region. The agriculture that lines the river fills the floodplain
on the floor of the river valley, which averages about 6 miles across in the image
above. The boundary between the green and beige marks the valley walls.
Below, the Nile River delta on the Mediterranean Sea can be seen in a 2003 image
from NASA’s Terra satellite and below that, close up in a photo from GeoEye.
Images: 1) USGS/NASA. 2) NASA. 3) GeoEye.
Lena River, Siberia
The Lena River is the world’s 10th longest, stretching 2,800 miles and draining
almost a million square miles of Siberia. The Lena’s delta, shown here in a false-color
image taken by the Landsat 7 satellite in 2000, covers more than 11,000 square miles
on the Laptev Sea. The delta is frozen tundra for around seven months of the year. For
a few months it is wetlands and is protected as a wildlife reserve.
Colorado and Green Rivers, Utah
The Green River (on the left) meets the Colorado River in the middle of Canyonlands
National Park, Utah, in this image from GeoEye. Cataract Canyon begins just below
the confluence, and contains a very popular stretch of water for river rafters, dotted
with rapids.
The circular structure in the upper left corner of the image is Upheaval Dome, named
because geologists suspected it was formed when layers of earth were pushed up by a
buoyant pocket of salt, known as a salt diapir. Since then, however, geologists have
determined it was caused by an asteroid impact. Upheaval Dome can be seen close up
in the image below taken by astronauts aboard the International Space Station in

Images: 1) GeoEye. 2) NASA.
Alluvial Fan, Tibet
Lake Morari on the Tibetan Plateau is fed by a glacial river that has formed a dramatic
apron of sediment, known as an alluvial fan, over the years. The fan grew big enough
to dam the river and form the lake. The water must go back around and through the
fan sediments to drain through the lake’s outlet on the left side of this image, taken by
astronauts aboard the International Space Station in 2006.

Image: NASA
Mackenzie River, Canada
The Mackenzie is Canada’s longest river, and the second longest in North America,
running 2,635 miles from Great Slave Lake to the Beaufort Sea. The delta, pictured
here in a false-color image captured by the ASTER instrument aboard NASA’s Terra
satellite in August 2005, is a giant marsh riddled with lakes. Near the top of this
image, a bend in the river has almost separated from the main channel to become an
oxbow lake.
Niagara Falls
Though a satellite’s view of a vertical feature on Earth may not be the most flattering
angle, this image of Niagara Falls is impressive. The Niagara River drops nearly 170
feet to form one of the world’s largest waterfall, shown above in an image taken by
GeoEye’s Ikonos satellite in August 2004. More than 1.7 million gallons of water
runs over the edge every second, constantly eating away at the rock below and
pushing it back as much as 20 feet in a year.
A close-up of the falls from the same image is below, reoriented for a better
perspective. Below that is a view of the entire Niagara River between Lake Ontario in
the north and Lake Erie in the south, taken by astronauts aboard the International
Space Station in 2007.
Images: 1) GeoEye. 2) GeoEye. 3) NASA.

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