4: Earth, Moon, and Sky

Question 1

circle of latitude above South Pole at 67° S - 24-hour period of darkness during summer solstice, sunlight during winter solstice

Answer 1

Antarctic Circle

Question 2

the angular distance north or south of the celestial equator

Answer 2

declination

Question 3

alternate rising and falling of sea level caused by the difference in the strength of the Moon’s gravitational pull on different parts of Earth

Answer 3

tides

Question 4

Earth’s rotation period as defined by the position of the Sun in the sky; the time between successive passages of the Sun through the meridian

Answer 4

solar day

Question 5

arbitrary line on the surface of Earth near longitude 180° across which the date changes by one day

Answer 5

International Date Line

Question 6

town designated as the Prime Meridian of the world, with a longitude of 0 degrees

Answer 6

Greenwich, England

Question 7

the period of the Moon’s revolution about Earth measured with respect to the stars

Answer 7

sidereal month

Question 8

latitude where the Sun appears directly overhead (at zenith) at noon during the summer solstice (23° N)

Answer 8

Tropic of Cancer

Question 9

the time interval in which the phases repeat - say, from full to full phase

Answer 9

solar month

Question 10

an eclipse of the Sun by the Moon, caused by the passage of the Moon in front of the Sun - can occur only at the time of the new moon

Answer 10

solar eclipse

Question 11

the coordinate for measuring the east-west positions of celestial bodies; the angle measured eastward along the celestial equator from the vernal equinox to the hour circle passing through a body

Answer 11

right ascension (RA)

Question 12

latitude where the Sun appears directly overhead (at zenith) at noon during the winter solstice (23° S)

Answer 12

Tropic of Capricorn

Question 13

an eclipse of the Moon, in which the Moon moves into the shadow of Earth - can occur only at the time of full moon

Answer 13

lunar eclipse

Question 14

a circle on the surface of a sphere that is the curve of intersection of the sphere with a plane passing through its center

Answer 14

great circle

Question 15

larger-than-average tides created when Sun and Moon are lined up with one another (new or full Moon)

Answer 15

spring tides

Question 16

circle of latitude below North Pole at 67° N - 24-hour period of sunlight during summer solstice, darkness during winter solstice

Answer 16

Arctic Circle

Question 17

Earth’s rotation period as defined by the positions of the stars in the sky; the time between successive passages of the same star through the meridian

Answer 17

sidereal day

Question 18

time as measured by the position of the Sun in the sky (the time that would be indicated by a sundial)

Answer 18

apparent solar time

Question 19

lower-than-average tides created when Moon is at a right angle to the Sun’s direction

Answer 19

neap tides

Question 20

June 21 - day in which the Sun shines down most directly upon the Northern Hemisphere (longest day)

Answer 20

summer solstice

Question 21

when a body (for example, the Moon) rotates at the same rate that it revolves around another body

Answer 21

synchronous rotation

Question 22

December 21 - day in which Northern Hemisphere receives the least sunlight (shortest day)

Answer 22

winter solstice

Question 23

time based on the rotation of Earth - passes at a constant rate, unlike apparent solar time

Answer 23

mean solar time

Question 24

the different appearance of light and dark on the Moon as seen from Earth during its monthly cycle, from new moon to full moon and back to new moon

Answer 24

phases of the Moon

Question 25

point in the sky where ecliptic (Sun’s path) crosses the celestial equator - starting point for calculating right ascension

Answer 25

vernal equinox

Question 26

a great circle on the terrestrial or celestial sphere that passes through the poles

Answer 26

meridian