Chapter 1

Question 1

Galaxy

Answer 1

A great island of stars in space containing billion/trillions of stars

Question 2

Local Group

Answer 2

The group of about 40 galaxy within the Milky Way

Question 3

Super clusters

Answer 3

The largest known structures in the universe consists of galaxies, groups of galaxies and individual galaxies

Question 4

1 Astronomical Unit (AU)

Answer 4

Earth’s average distance from the Sun about 150 million km/93 million miles

Question 5

1 Light Year

Answer 5

The distance light can travel in one year

Question 6

Speed of Light

Answer 6

300,000 km/s

Question 7

Star

Answer 7

large glowing ball of gas that generates heat and light through nuclear fusion at it’s core

Question 8

Planet

Answer 8

Orbits a star, is large enough to have it’s own gravity and cleared most orbital objects in it’s path

Question 9

Moon/Satellite

Answer 9

An object that orbits a planet

Question 10

Asteroid

Answer 10

A relatively small and rocky object that orbits a star

Question 11

Comet

Answer 11

a relatively small ice rich object that orbits a star

Question 12

Solar System Body

Answer 12

Any asteroid/comet/other object that orbits a star but it’s too small to qualify

Question 13

Cluster of Galaxies

Answer 13

A collection of galaxies bound together by gravity
small: groups
large: clusters

Question 14

Orbits/Revolutions

Answer 14

The orbital motion of one object around another due to gravity

Question 15

Expansion

Answer 15

The increase in the avg. distance between galaxies as time progresses

Question 16

Observable Universe

Answer 16

The portion of the universe that can be seen from Earth

Question 17

Light Year

Answer 17

10 trillion km

Question 18

Nuclear Fusion

Answer 18

The process in which two/more smaller nuclei slam together and make one larger nucleus

Question 19

Ecliptic Plane

Answer 19

The plane of the Earth’s orbit around the Sun

Question 20

Axis’ Tilt

Answer 20

The amount by which a planets axis is tilted with respect to a line perpendicular to the ecliptic plane.

Question 21

Dark Matter

Answer 21

Matter that we can infer exists from its gravitational effects but from which we have not detected any light.

Question 22

Dark Energy

Answer 22

The theoretical repulsive force that counteracts gravity and causes the universe to expand at an accelerating rate

Question 23

Copernican Revolution

Answer 23

The shift from geocentric understanding to a heliocentric understanding

Question 24

Probes

Answer 24

A device/substance used to examine/orbit information
Ex: Voyager 1 and Voyager 2, Juno, etc.

Question 25

North Star

Answer 25

Polaris

Question 26

The Ecliptic

Answer 26

The imaginary plane containing the Earth's orbit around the Sun

Question 27

Meridian

Answer 27

Line passing through the zenith and connecting the North and South

Question 28

Zenith

Answer 28

The imaginary point directly above an observer on the celestial sphere

Question 29

Horizon

Answer 29

All points 90 degrees from the zenith

Question 30

1 degree

Answer 30

= 60 arc minutes = 120 arc seconds

Question 31

Angular Size (formula)

Answer 31

θ=(X×360∘/2π×d)

Question 32

Angular Size (definition)

Answer 32

Our measure of the angle formed by extending imaging lines outward from our eyes to span an object.

Question 33

Circumpolar

Answer 33

Continually visible above the horizon

Question 34

Seasons are based on ________?

Answer 34

The Earth's tilt