Lesson 2: Vocabulary

Question 1

Heliocentric

Answer 1

Sun centered universe.

Question 2

Configuration

Answer 2

Geometrical arrangements of the planets.

Question 3

Superior Conjunction

Answer 3

When an inner planet is in the opposite side of the sun.

Question 4

Greatest Western Elongation

Answer 4

The farthest west a planet reaches.

Question 5

Conjunction

Answer 5

When a planet is lined up directly behind the Sun.

Question 6

Aristotle

Answer 6

Proposed a theory of the universe that entailed two types of motion: towards/away from and around.

Question 7

Retrograde Motion

Answer 7

When a planet appears to stop, move backwards, and then start moving forward again.

Question 8

Epicycles

Answer 8

Spheres within spheres. The smaller sphere.

Question 9

Ptolemy

Answer 9

Able to predict the exact location of the planets by using epicycles in Aristotle’s theory.

Question 10

Aristarchus

Answer 10

Proposed the heliocentric theory-a sun centered universe.

Question 11

Geocentric

Answer 11

An earth centered universe.

Question 12

Eratosthenes

Answer 12

Calculated the circumference of the earth.

Question 13

Copernicus

Answer 13

Determined the order of the planets and detailed the advantages of a heliocentric cosmology.

Question 14

Inferior Conjunction

Answer 14

When an inner planet is lined up between the earth and the sun.

Question 15

Greatest Eastern Elongation

Answer 15

A planet is as far east of the Sun as it can be.

Question 16

Opposition

Answer 16

The planet is on the opposite side of the earth (from the Sun).

Question 17

Period

Answer 17

The amount of time it takes to complete one revolution.

Question 18

Synodic Period

Answer 18

The time that elapses between two successive identical configurations.

Question 19

Sidereal Period

Answer 19

The true orbital person of a planet.

Question 20

Kepler

Answer 20

First scientist to propose that planetary orbits are not circles.

Question 21

Ellipse

Answer 21

A curve shaped like an oval; planets revolve around the Sun in these.

Question 22

Kepler’s First Law

Answer 22

The planets orbit the Sun in an ellipse with the Sun at one focus.

Question 23

Perihelion

Answer 23

A planet moves more rapidly when it is nearest the Sun.

Question 24

Aphelion

Answer 24

A planet moves more slowly when it is farthest from the Sun.

Question 25

Kepler’s Second Law

Answer 25

A line joining a planet and the sun sweeps out equal areas in equal intervals of time.

Question 26

Kepler’s Third Law

Answer 26

The squares of the sidereal period of the planets are proportional to the cubes of the semi major axes of their orbits. (P^2 = a^3)

Question 27

Galileo

Answer 27

First person to use the telescope, discovered that Venus has phases, Jupiter has moons, the Sun has spots, and saw mountains on the Moon.

Question 28

Newton’s Law of Inertia

Answer 28

An object at rest or in constant motion will remain that way unless acted upon by an unbalanced force.

Question 29

Newton’s Law of Acceleration

Answer 29

The acceleration of an object is proportional to the force acting on it. (F = ma)

Question 30

Newton’s Law of Reactions

Answer 30

For every action force, there is an equal and opposite reaction force.

Question 31

Newton’s Law of Universal Gravitation

Answer 31

Fg = (Gm1m2)/(d^2)

Question 32

Einstein

Answer 32

Proposed a theory called general relativity.

Question 33

General Relativity

Answer 33

Gravity was not a force, but rather “curved space”.

Question 34

Gravitational Lensing

Answer 34

The curvature of space (gravity) actually bends the path of light.

Question 35

Deferent

Answer 35

The larger sphere in an epicycle.