The Cosmic Perspective 5Th Edition Chapter 1

Front 1

Geocentrism

Back 1

The interpretation that the universe is earth-centered.

Front 2

Our solar system

Back 2

The sun and all the objects that orbit it |

Front 3

Galaxy

Back 3

"a great island of stars in space, containing from a few hundred million to a trillion or more stars"

Front 4

Milky Way

Back 4

Our galaxy, a large galaxy containing more than 100 billion stars. Member of the LOCAL GROUP

Front 5

Galaxy clusters

Back 5

Groups of galaxies with more than a few dozen members

Front 6

Universe

Back 6

the sum total of all matter and energy, encompassing the superclusters and voids and everything within them.

Front 7

Is the universe expanding, contracting, or staying the same?

Back 7

Expanding

Front 8

Big Bang

Back 8

Start of expansion of the universe, approx 14 billion years ago

Front 9

Birth of our solar system

Back 9

4.5 billion years ago

Front 10

The only two chemical elements in the early universe

Back 10

Hydrogen and helium

Front 11

Gravity

Back 11

Force that causes gas and dust to form stars and planets

Front 12

Nuclear fusion

Back 12

The beginning of a star, gravity compresses a material in the cloud to the point where the center becomes dense and hot enough to generate energy from nuclear fusion - the process in which lightweight atomic nuclei smash together to make heavier nuclei

Front 13

Supernovae

Back 13

An explosion signifying the death of a star

Front 14

Star

Back 14

A large glowing ball of gas that generates heat and light through nuclear fusion in its core--such as our sun

Front 15

Planet

Back 15

A moderately large object that orbits a star and shines primarily by reflecting light from its star. Three modern conditions 1: orbits a star, 2: is large enough for its own gravity to make it round 3: has cleared most other objects from orbital path.

Front 16

moon

Back 16

An object that orbits a planet

Front 17

Asteroid

Back 17

Small and rocky object that orbits a star.

Front 18

Comet

Back 18

Relatively small and ice-rich object that orbits a star.

Front 19

Supercluster

Back 19

Gigantic region of space where many individual galaxies and many groups and clusters of galaxies are packed more closely together than elsewhere in the universe.

Front 20

Light-year

Back 20

the DISTANCE that light can travel in 1 year, which is about 9.46 trillion kilometers.

Front 21

Rotation

Back 21

The spinning of an object around its axis

Front 22

Orbit (revolution)

Back 22

The orbital motion of one object around another

Front 23

Observable universe

Back 23

the Portion of the entire universe that we can potentially observe--things that lie within 14 billion light-year of earth.

Front 24

Great Red Spot

Back 24

Storm on Jupiter's surface

Front 25

How many stars in the Milky Way

Back 25

100 Billion

Front 26

Cosmic calendar

Back 26

analogizing the history of the universe into 1 year, with big bang at january 1 etc.

Front 27

Direction that earth rotates

Back 27

West to east--counterclockwise as viewed from above the north pole.

Front 28

Astronomical unit (AU)

Back 28

Earth's average orbital distance

Front 29

Ecliptic plane

Back 29

Earth's orbital path, a flat plane

Front 30

Earth's axis tilt

Back 30

23 and 1/2 from a line perpendicular to the ecliptic plane. Oriented so the earth points almost directly at a star called Polaris, or the North Star.

Front 31

Local solar neighborhood

Back 31

the region of the sun and nearby stars

Front 32

Copernican revolution

Back 32

The discovery that earth is not the center of the universe but rather just one planet orbiting the sun.