Chapter 4

Question 1

Aphelion

Answer 1

planet is furthest from the sun

Question 2

ellipse and foci

Answer 2

a closed curve for which the sum of the distances from two fixed point (the foci) is the same for every point on the curve.

Question 3

greastest elongation

Answer 3

the greatest angular distance between a sun and planet

Question 4

heliocentric

Answer 4

orbits around the sun

Question 5

impetus theory

Answer 5

motion was also a natural state of things and permanent unless something resisted the motion

Question 6

inferior planet

Answer 6

planets with smaller orbits and shorter sidereal periods

Question 7

Keplers laws of planetary motion

Answer 7

1. a planet moves at an elliptical orbit with the sun at one foci
2. a planet moves so that an imaginary line connecting the planet the sun sweeps out equal areas in equal intervals of time.
3. the square of a planets sidereal period are proportional to the cubes of the semi major axis p2 = a3

Question 8

Perihelion

Answer 8

planet is closest to the sun

Question 9

sidereal period

Answer 9

length of time it takes a planet to complete its orbit around the sun

Question 10

stellar parallax

Answer 10

the annual apparent change in the position of the stars caused by the motion of the earth around the sun

Question 11

superior planet

Answer 11

planets with larger orbits and longer sidereal periods than earth

Question 12

transverse velocity

Answer 12

objects speed up when closer to the thing they orbit and slow down the further away they get

Question 13

1/S=1/p1 - 1/p2

Answer 13

s is synodic period, p1 is inner faster planet, p2 is outer slower planet.