alleryStart learning →What does Kepler's first law state about a planet's orbit around the sun?
AIt is an ellipse with the sun at one focus
BIt is a perfect circle centered on the sun
CIt is an ellipse with the sun at its center
DIt is a spiral that slowly moves outward
Answer & Solution
Correct answer: A. It is an ellipse with the sun at one focus
1. Kepler's first law describes the shape of every planet's orbit.
2. That shape is an ellipse, not a circle, and the sun sits at one of its two foci rather than at its center.
3. A circle only appears as the special case where the ellipse's eccentricity is zero.
_Source: OpenStax Physics (CC BY 4.0), Ch 7 "Newton's Law of Gravitation", section 7.1 Kepler's Laws of Planetary Motion_
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