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Get to know your planet better

It doesn’t take much to get scientists geeking out over satellite images of Earth, but some shots are stunning enough to serve as art for art’s sake. This week, the U.S. Geological Survey released the third in its series of award winning USGS and NASA images made with the Landsat 5 and Landsat 7 satellites. You can check out a slideshow of the images here.

“These remarkably engaging portraits of Earth encourage us all to learn more about our complex world,” Matt Larsen, the associate director for climate and land use change at the USGS, said in a news release about the images.


The Landsat satellites are part of the joint USGS and NASA Earth-observing missions, which have been making images of the planet since 1972. Every 16 days, the satellites image the entire Earth. Beyond their beauty, the images are used for a host of scientific purposes, Larsen explained.

For example, images of the southeast coast of Greenland allow scientists "to monitor changes in the ice cover, which is a huge challenge in calibrating," he told me. Scientists have become alarmed in recent years at the accelerated melt rate of the Greenland ice sheet. Similarly, scientists use the regular images to monitor sea ice cover in the Arctic. It reached its lowest extent in 2007. This year was the third lowest.

But the 40 images in the "Earth as Art 3" exhibit were selected for solely for their aesthetic appeal. They show cloud formations, coastlines, mountain ranges, islands, deltas, glaciers, and rivers -- all them looking more like abstract art than the familiar features we see from the ground. That’s partly because, unlike the human eye, the Landsat sensors "see" the Earth only in bands of red, green, blue and infrared light. When combined into a single image, "fascinating patterns, colors, and shapes emerge," according to the USGS.

The image release coincides with Geography Awareness Week 2010, an annual event that highlights the importance of geographic understanding for U.S. economic competitiveness, national security, environmental sustainability and the livability of our communities in the 21st century. This year’s theme is freshwater -- an increasingly scarce resource on a planet with a growing human population and a changing climate.

Most of Earth’s water is salty -- think the oceans. Only about 3 percent of the supply is freshwater, and most of that water is frozen in the icecaps on Antarctica and Greenland, locked up as soil moisture, or in underground aquifers inaccessible to humans, according to the USGS. That leaves less than 1 percent of all the water on the planet available for human use.

You can test your knowledge of freshwater and geography by taking Northern Arizona University’s Geography Awareness Week 2010 Quiz. It’s too late to win a prize from the university, which were already handed out to geographically inclined students at Northern Arizona. First place went to Terri Victor, who answered 24 of the 25 questions correctly. Joseph Ali Guvendiren and Richard Immell tied for second with 23 out of 25, and Jeremy McWhorter and Jordan Morrison tied for third with 22 correct answers.

Still want to compete? Try your hand on the first five questions below. The first U.S. resident to list the five correct answers in a comment will receive a hard copy of the "Earth as Art 3" publication. The winner -- and the answers -- will be announced in a follow-up comment.

1. In order to generate hydroelectric power, one of the world’s largest artificial lakes was created in Ghana in 1965. Name this body of water.

a. Lake Nicaragua
b. Lake Kariba
c. Lake Powell
d. Lake Volta

2. The Coco River forms part of the boundary between Honduras and which neighboring country?

a. Nicaragua
b. El Salvador
c. Guatemala
d. Belize

3. Which is one of the main reasons dams are built across rivers -- to create oxbow lakes OR to control seasonal flooding?

a. to create oxbow lakes
b. control seasonal flooding

4. Which river is known as China’s Sorrow because of its history of disastrous floods?

a. Yellow
b. Ting
c. Mekong
d. Panlong

5. The Greek word meaning “the country between two rivers” is the historical name for what region located between the Tigris and
Euphrates Rivers?

a. Iraq
b. Furat
c. Jordan
d. Mesopotamia

If you didn't win the "Earth as Art 3" prize, don't despair. NASA astronaut Scott Kelly, the International Space Station's current commander, has set up a geography trivia game you can play using Twitter. The winner of each round gets a "congratulatory tweet" from Kelly, and will receive an autographed picture of an Earth view after Kelly's return to Earth nest spring.

I'd also like to welcome John Roach, a longtime contributor to msnbc.com and other publications, as a co-blogger for Cosmic Log. Last weekend marked exactly eight and a half years since we started up Cosmic Log (on May 13, 2002), and John's contributions will help ensure that the log keeps rolling for years to come. You can become part of the Cosmic Log community as well, by weighing in with your comments here and by clicking the "like" button on the Cosmic Log page on Facebook.