1.6 Solar vs. Sidereal Time
Pre-Lecture Reading 1.6
Video Lecture
Supplementary Notes
Earth's Daily and Yearly Motions
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Earth rotates (spins) 360° on its axis every sidereal day.
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1 sidereal day = 24 sidereal hours = 23:56 solar hours
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1 solar day = 24 solar hours
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Earth revolves (orbits) 360° around the sun every 365.24 solar days. This is called a tropical year.
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Earth revolves ≈1° around the sun every day.
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Earth rotates 1° on its axis every 4 sidereal minutes.
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1 sidereal day + 4 sidereal minutes = 1 solar day
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Hence, the sidereal day is shorter than the solar day.
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Hence, stars rise and set 4 sidereal minutes earlier every solar day.
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Hence, nighttime constellations shift seasonally.
Exercises
Assignment 1
Do Question 3.
