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Celestial Navigation

April 10, 2013

The stars of the Big Dipper wheel high across the north this evening, circling up and over Polaris, the North Star. At the same time, the stars of W-shaped Cassiopeia, the queen, wheel below the North Star.

These star patterns and their motions across the sky have been helping navigators find their way at sea for centuries. And they may have been helping others find their way for much longer.

There’s evidence that birds and some other creatures navigate with the help of the stars. For many, it’s the most prominent star in the sky: the Sun. A monarch butterfly, for example, uses its antennae as a sort of sundial. Combined with an internal clock, that helps them migrate thousands of miles between the United States and Mexico.

Other creatures may use the Sun during the day and the brighter stars at night. Scientists have put caged birds in planetariums and fiddled with the depiction of the sky. The experiments show that warblers, buntings, and other birds appear to use the North Star, the rotation of stars around the North Star, or other stellar configurations to help them migrate.

Experiments have shown that other types of creatures also use the sky for navigation, from tiny shrimp-like creatures on the beach to newts in Spain.

The stars aren’t the only way these creatures navigate - they use landmarks, smells, and even Earth’s magnetic field. But the stars of the night sky - and daytime sky - help many creatures travel across the globe.


Script by Damond Benningfield, Copyright 2013

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