Lecture 5 : the grocentric vs heliocentric model

Question 1

The Greek’s thought the Universe was made of 4 —-1—- (earth, water, air and fire)
* The celestial sphere was —2—, made with —3— to let the fire behind pass through in the form of stars.
* They believed in the —-4—- model
✓ —-5—–of the Moon
✓ E——–(5)

Answer 1

1)elements
2)real
3)holes
4)geocentric
5) Phases
6)Eclipses

Question 2

Issues with geocentric model

The Sun, Moon and planets move —-1—- with respect to the stars
(direct motion). Note: this is regardless of their rising in the —2— and setting in the —3— .
* However, some planets seem to have some kind of “—-4—- motion” where they move —-5—– for a few days.

Answer 2

1) eastward
2) east
3) west
4) retrograde
5) westward

Question 3

The Ptolemaic System

Each planet moves in small circles called —1—- , which at the same time moves around a larger circle called —2—-, —3—- at Earth.
The problem with this system is that it treats each planet —4— .
* There is no model for which an underlying —-5—- ——— can be applied to all planets

Answer 3

1) epicycles
2) deferent
3) centered
4) independently
5) physical principle

Question 4

Synodic period: time that elapses between two —-1—- identical —-2—– as seen from Earth.

Sidereal period: true —3— period of a planet (time it takes the planet to complete one full orbit around the Sun)

Answer 4

1)successive
2)configurations
3)orbital

Question 5

More evidences of Earth’s rotation
around its axis: p—-1—-

Closer object to –2— : bigger parallax.
Very —3— stars: almost no parallax

Answer 5

1)parallax
2)earth
3)distant

Question 6

Each planet’s path around the Sun is an —-1——,
with the Sun at one —-2— of the ellipse

Answer 6

1) ellipse
2) centre

Question 7

A planet moves along its elliptical path with a
—1— that —-2— in such a way that a line
from the planet to the Sun sweeps out —-3—-
areas in equal intervals of —-4—

Answer 7

1)speed
2)changes
3)equal
4)time

Question 8

The –1— of a planet’s (or minor body) —-2—
—3— is —-4— to the —5— of its semi-
major axis

Answer 8

1)square
2)orbital
3)period
4)proportional
5)cube