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A series of Landsat satellites have surveyed the Earth's surface since 1972.
In that time, Landsat data have become a vital reference worldwide,
used for understanding scientific issues related to land use and natural resources.
However, some Landsat images are simply striking to look at,
presenting spectacular views of mountains and valleys, forests and farms.
To celebrate the 40th anniversary of Landsat, the U.S. Geological Survey
and NASA asked for your help in selecting the top five Earth As Art images.
Number Five – Lake Eyre
Patches of shallow water in Australia's Lake Eyre resemble a skull.
This ephemeral feature occurs in a flat, often parched landscape.
Lake Eyre is Australia's largest lake – when it's full.
However, in the last 150 years, Lake Eyre has only been full three times.
Number Four – Algerian Abstract
What looks like pale yellow streaks of paint
slashing through a mosaic of mottled colors are ridges of wind-blown sand
that make up a sea of sand extending from Algeria into Mauritania, in northwestern Africa.
In this area of ever-shifting sand, one of several in the Sahara,
individual dunes often surpass 500 meters –
nearly a third of a mile – in both width and height.
The light blue areas in the image are salt crusts left behind from the evaporation of the valley's water.
Number Three – Meandering Mississippi
Small blocky shapes of towns, fields, and pastures
surround the graceful swirls and whorls of the Mississippi River.
Numerous oxbow lakes and cutoffs run along the
meandering river south of Memphis, Tennessee,
on the border between Arkansas and Mississippi.
The "Mighty Mississippi" is the largest river system in North America.
Number Two – Yukon Delta
Beginning in British Columbia and flowing through Yukon, in Canada,
the Yukon River crosses Alaska before emptying into the Bering Sea.
Countless lakes, sloughs, and ponds
are scattered throughout this scene of the Yukon Delta.
The sinuous, branching waterways resemble blood vessels reaching out to enclose an organ.
It is one of the largest river deltas in the world,
and is protected as part of the Yukon Delta National Wildlife Refuge.
Number One – Van Gogh From Space
In the style of Van Gogh's painting "Starry Night,"
massive congregatinos of greenish phytoplankton swirl in the dark water around Gotland,
a Swedish Island in the Baltic Sea.
Phytoplankton are microscopic marine plants that form the first link in nearly all ocean food chains.
Population explosions, or blooms of phytoplankton, like the one shown here,
occur when deep currents bring nutrients up to sunlit surface waters,
fueling the growth and reproduction of these tiny plants.
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