2: Observing the Sky - The Birth of Astronomy

Question 1

to change velocity; to speed up, slow down, or change direction

Answer 1

accelerate

Question 2

Hipparchus’ measure of how bright a star looks in the sky - the larger the number, the dimmer the star

Answer 2

apparent magnitude

Question 3

ancient belief that the positions of celestial bodies in the zodiac hold the key to understanding life, human destiny

Answer 3

astrology

Question 4

line that lies halfway between the celestial poles - extension of Earth’s

Answer 4

celestial equator

Question 5

the points where Earth’s axis intersects the celestial sphere

Answer 5

celestial poles

Question 6

outdated view of the sky as a large sphere with stars embedded in it that orbits around the earth

Answer 6

celestial sphere

Question 7

area of the sky between the north and south celestial poles

Answer 7

circumpolar zone

Question 8

our concept of the basic structure and origin of the cosmos

Answer 8

cosmology

Question 9

path the Sun appears to take around the celestial sphere each year

Answer 9

ecliptic

Question 10

Ptolemy’s term for a unique small orbit that each planet has - used to explain retrograde motion

Answer 10

epicycle

Question 11

early Earth-centric view of the universe in which everything else revolves around us - widely believed until European Renaissance

Answer 11

geocentric

Question 12

Sun-centered model of the Solar System in which all planets orbit around it

Answer 12

heliocentric

Question 13

a great circle on the celestial sphere 90° from the zenith; more popularly, the circle
around us where the dome of the sky meets Earth

Answer 13

horizon (astronomical)

Question 14

a chart used by astrologers that shows the positions along the zodiac and in the sky of the Sun, Moon, and planets at some given instant and as seen from a particular place on Earth—usually corresponding to the time and place of a person’s birth

Answer 14

horoscope

Question 15

apparent shift in the direction of an object as a result of the motion of the observer

Answer 15

parallax

Question 16

today, any of the larger objects revolving about the Sun or any similar objects that orbit other stars; in ancient times, any object that moved regularly among the fixed stars

Answer 16

planet

Question 17

the slow but consistent motion of Earth’s axis of rotation - point of axis in the sky changes as time goes on

Answer 17

precession (of Earth)

Question 18

the temporary apparent westward movement of a planet as Earth swings between it and the Sun

Answer 18

retrograde motion

Question 19

unit of time it takes for the Earth to orbit fully around the Sun once

Answer 19

year

Question 20

the point of the sky directly above an observer’s head

Answer 20

zenith

Question 21

a belt around the sky about 18 degrees wide centered on the ecliptic - includes planets, Sun, Moon, constellations

Answer 21

zodiac

Question 22

Greek philosopher who argued the Earth was round, citing the phases of the Moon and appearance of observable stars

Answer 22

Aristotle

Question 23

ancient Greek term for the planets (+ Sun and Moon), noticing their independent movements across the night sky

Answer 23

wandering stars

Question 24

Polish cleric who developed heliocentric model of the solar system and arranged the planets in correct order

Answer 24

Nicolaus Copernicus

Question 25

theater in which a simulation of the stars and planets (celestial sphere) is projected onto a white dome

Answer 25

planetarium

Question 26

star near the north celestial pole that moves the least amount each day, became significant in certain mythologies

Answer 26

Polaris

Question 27

Greek mathematician who made first fairly accurate measurement of Earth’s diameter by observing sunlight and shadows

Answer 27

Eratosthenes