Chapter 2 Terms Flashcards Preview

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Flashcards in Chapter 2 Terms Deck (11):
1

Angular Size

A measure of how large an object looks to you

2

Ellipse

A geometric figure related to a circle but flattened into an oval shape

3

Epicycle

Where each planet moved on one small circle, when in turn moved onto a large one

4

Focus

A point within an ellipse used to generate the eliptical shape and an optical system in which light rays are brought together

5

Geoncentric Model

That the Earth was the center of the Solar System, not the Sun

6

Heliocentric Moel

That the Sun is the center of the Solar System

7

Kepler's Three Laws

1st Law is that planets move in an elliptical orbit. 2nd Law is when a planet is near the sun, It orbits more rapidly. The 3rd law is the mass of the planet is = to the amount it takes it to orbit the sun.

8

Moon Illusion

Illusion that the moon appears larger when near the Horizon

9

Parallax

The shift in an object's position caused by the observer's motion

10

Retrograde Motion

The drift of a planet westward against the background stars

11

Semimajor Axis

Half the long dimension of an ellipse