This picture is of the Andes Mountains between Chile and Argentina in South America. It was taken from the International Space Station. Do you see the glaciers and snow on top of the mountains? Do you see the lakes in the valleys between mountains?
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NASA Earth Observatory


This picture was taken from high above our planet. Looking at the Earth from very far away like this we can see that some parts of our planet look light in color, and some parts look dark.

The color of these parts affects what happens when sunshine hit them. If the Sun's rays hit a dark part, like an ocean or forest, most of the rays are absorbed. Very few are reflected back out to space. If the Sun's rays hit a light colored part of the Earth's surface, like snow or ice, most of the rays are reflected back out to space. Only a few rays are absorbed. The amount of the Sun's energy that is reflected is called albedo.

Dark colored things like oceans and forests have low albedo. Light colored things like snow and ice have very high albedo. About two out of three of the Sun's rays that get to Earth are reflected out to space and the other one is absorbed.

The albedo of each planet or moon depends on what is at its surface. Some planets are so far away that they are difficult to see with telescopes. But scientists can figure out what the planet is made of if they can measure its albedo.

Earth's climate depends on how many of the Sun's rays are reflected back out to space and how many are absorbed. As our planet gets warmer, more snow and ice melt. Fewer of the Sun's rays are reflected out to space. More are absorbed. This is causing even more warming.

Clouds affect albedo too. They have a high albedo and reflect solar energy out to space. If there were no clouds, Earth's average albedo would drop by half.


Last modified May 13, 2011 by Jennifer Bergman.

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