Chapter 3

Question 1

moonrise/set times

Answer 1

New moon – sunrise to sunset
1st quarter – noon to midnight
Full moon – sunset to sunrise
3rd quarter – midnight to noon

Question 2

synchronous rotation

Answer 2

when an object rotates once during an orbit; this causes one side of the moon to always face away from Earth

Question 3

siderial month

Answer 3

amount of time required for the moon to complete one full orbit of Earth with respect to the stars

27.32 days

Question 4

synodic month

Answer 4

also known as lunar month; equal to a lunar day

time required for the moon to complete a full cycle of phases (based on sun)

29.53 days

Question 5

inclination of moon’s orbit

Answer 5

about 5 degrees from Earth’s orbit (the ecliptic)

Question 6

line of nodes

Answer 6

intersection of the moon and Earth’s orbital planes

eclipses can only occur when the sun and moon lie on the line of nodes

Question 7

phases of eclipses

Answer 7

solar eclipses only occur at new moon and lunar eclipses only occur at full moon

Question 8

umbra

Answer 8

the fully shaded inner region of a shadow cast by an opaque object, especially the area on the earth or moon experiencing the total phase of an eclipse

Question 9

penumbra

Answer 9

the partially shaded outer region of the shadow cast by an opaque object.

Question 10

classifications of lunar eclipse

Answer 10

penumbral, partial, total lunar eclipse

Question 11

maximum length of total lunar eclipse

Answer 11

1 h 42 min

Question 12

color of light which passes through Earth’s atmosphere

Answer 12

mostly red

causes the moon to appear red during an eclipse

Question 13

apogee

Answer 13

the point in the orbit of the moon or a satellite at which it is furthest from the earth

Question 14

annular solar eclipse

Answer 14

a solar eclipse where the moon does not completely cover the sun because it is near apogee

Question 15

perigee

Answer 15

the point in the orbit of the moon or a satellite at which it is closest to the earth

Question 16

eclipse year

Answer 16

the amount of time between identical allignments of the line of nodes

346.6 d

Question 17

saros

Answer 17

time between identical orientations of the earth, moon, and sun

they saros cycle is used to predict eclipses. it takes 3 saros cycles for an eclipse to fall on the same place again.

223 synodic months or 18 y 11d 8h

Question 18

ancient measurments of the size of the Earth

Answer 18

In 200 BCE Eratosthenes approximated the size of the Earth by comparing the angles of the sun at local noon in Alexandria and Syene.