Ch 31

Question 1

Variable star

Answer 1

Stars in the giant branch of the h-r diagram. They pulsate in brightness because their outer layers expand and contract

Question 2

RR Lyrae variable

Answer 2

A variable star that has a period of pulsation between 1.5h and 1 day. Has about the same brightness all the time

Question 3

Cepheid variable

Answer 3

Variable star with a pulsation period between 1 and 100 days.

Question 4

Halo

Answer 4

A spherical region in a galaxy where globular clusters are found

Question 5

Spiral density wave

Answer 5

Alternating dense and less-dense areas that are frozen in place and rotate as a rigid pattern

Question 6

Supercluster

Answer 6

A large cluster of galaxy clusters

Question 7

Hubble constant

Answer 7

Represents the slope of a moving Galaxy

Question 8

Radio Galaxy

Answer 8

A galaxy that emits as much or more radio energy as they do light. Often large and elliptical

Question 9

Active galactic nuclei

Answer 9

Highly energetic objects in galaxies are located here

Question 10

Quasar

Answer 10

Starlike object with emission lines in its spectra

Question 11

Cosmology

Answer 11

The study of the universe, it’s current nature, and it’s orgin

Question 12

Big Bang theory

Answer 12

The theory that the universe began as a point and has been expanding ever since

Question 13

Steady state theory

Answer 13

Theory that the universe looks the same on large scales to all observers and it’s always been that way!!!

Question 14

Cosmic background radiation

Answer 14

Weak radiation that appeared to come from all direction in space

Question 15

Inflationary universe model

Answer 15

The theory that the universe began as a fluctuation in a vacuum and expanded very rapidly for a fraction of a second