AST-101beginner

Earth's Rotation & Orbit: Foundations

Earth has two independent motions that dominate the apparent sky: a roughly 24-hour rotation about its axis and a roughly one-year revolution around the Sun. Rotation and orbital motion set the framework for civil time, sidereal time, telescope scheduling, seasonal star visibility, and the geometry used in spacecraft navigation.

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Earth's Rotation & Orbit: Foundations

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AST-100Doppler Shift, Redshift & Blueshift: Advanced Connections→

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AST-102Earth's Rotation & Orbit: Structures & Vocabulary→

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Earth has two independent motions that dominate the apparent sky: a roughly 24-hour rotation about its axis and a roughly one-year revolution around the Sun.

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Because Earth rotates eastward, the sky appears to move westward.

supported

The Foucault pendulum demonstrates Earth's rotation without reference to the sky, and stellar parallax provides direct geometric evidence that Earth changes position around the Sun.