Orbits and Gravity

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Tycho Brahe was a Danish astronomer who lived from 1546 to 1601.

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Tycho Brahe, a Danish astronomer, lived from 1546 to 1601 and was known for his contributions to astronomy.

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Tycho Brahe utilized his wealth to build an observatory and record planetary motion.

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Tycho Brahe used his wealth to construct an observatory and make precise records of planetary motion.

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Tycho Brahe built instruments to measure planetary positions with high accuracy.

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Tycho Brahe accurately built instruments to measure the positions of planets to about 1 arc minute.

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Tycho Brahe's achievement in planetary position

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Made precise records of planetary position.

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Tycho Brahe's discovery about comets

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Found that comets moved outside of Earth’s atmosphere.

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Tycho Brahe's observation in 1572

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Witnessed a supernova and concluded it was much farther away than any celestial sphere.

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Tycho Brahe's belief about planetary motion

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Held that the planets go around the sun, but the sun, in turn, orbits around Earth.

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Kepler's discovery about planetary motion

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Planets do not move in circles around the sun; they follow ellipses with the sun at one of the two foci.

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Definition of eccentricity in astronomy

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Eccentricity describes how round or "stretched out" an ellipse is. The higher the eccentricity, the flatter the ellipse.

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Definition of an ellipse

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An ellipse is a geometric form in the shape of an oval or circle, where the sum of the distances from two points (foci) to every point on the ellipse is constant.