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Definition
Any of the Ancient Greek models that were used to predict planetary positions under the assumption that Earth lay in the center of the Universe.
(Chp 3, Slide 5) |
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Definition
An ancient belief that the Earth is the center of the entire Universe
(Chp 3, Slide 5) |
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Definition
The model where the Sun is at center of the Universe and the Earth orbits like any other planet. Inferior planet orbits are smaller.
(Chp. 3, Slide 13)
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Term
| Apparent Retrograde Motion |
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Definition
Refers to the apparent motion of a planet, as viewed from Earth during the period of a few weeks or months when it moves westward relative to the stars in our sky.
we appear to "lap" Mars & the other superior planets.
(Chp 3, Slide 13 &22) |
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Term
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Definition
States that the orbit of each planet about the sun is an ellipse with the sun at one focus.
(Chp. 3, Slide 16) |
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| Kepler's Law of Planetary Motion |
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Definition
| Three laws discovered by Kepler that describe the motion of the planets around the sun. |
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Definition
States that, as a planet moves around its orbit, it sweeps out equal areas in equal areas in equal times. This tells us that a planet moves faster when it's closer to the Sun (near perihelion) than when it is farther from the sun (near aphelion) in its orbit.
(Chp. 3, Slide 18) |
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Term
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Definition
States that the square of a planet's orbital period is proportional to the cube of its average distance from the sun (semimajor axis) which tells us that more distant planets move more slowly in their orbits. In its written original form, written p^2=a^3.
(Chp.3, Slide 19) |
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