<p>This image of Arctic ice is a study in aging. Older, thicker ice contains fewer air pockets, giving the ice a light blue color. The gray ice is only a year old, and its thin structure lets some of the darker color of the seawater below show through.</p>

Black and Blue

This image of Arctic ice is a study in aging. Older, thicker ice contains fewer air pockets, giving the ice a light blue color. The gray ice is only a year old, and its thin structure lets some of the darker color of the seawater below show through.

Photograph by NASA Earth Observatory

Week's Best Space Pictures: Blue Ice and a Rocket Launch

Arctic ice changes color while volcanic gases swirl through the air in this week's best space pictures.

Arctic ice changes color while volcanic gases swirl through the air in this week's best space pictures.

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