Why do stars appear to traverse the heavens from east to west across the night sky?

Answer

Because the Earth spins on its axis toward the east, causing stationary objects to appear to move oppositely.

The apparent daily motion of celestial objects like stars, the Sun, and the Moon from east to west is an illusion directly caused by the Earth's rotation. The Earth is constantly spinning on its axis in the eastward direction, completing one full turn approximately every 24 hours. Since observers are situated on this rotating platform, stationary objects in the sky appear to swing in the opposite direction—that is, westward—across the observer's field of view. This effect is fundamental to understanding celestial observation from any fixed point on the planet, barring extreme polar locations where rising and setting are replaced by circling the horizon.

Related Questions

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