Quiz 6

Question 1

About 380,000 years after the big bang

Answer 1

Matter and radiation decoupled

Question 2

The radio emission seen from a typical radio galaxy

Answer 2

Comes from its radio lobes

Question 3

What do we call galaxies that seem to have the nuclear bulge and disk of a spiral but no arms?

Answer 3

Lenticular

Question 4

The steady state theory is a real theory

Answer 4

True

Question 5

According to the density wave theory, star formation would be seen

Answer 5

on the inside edge of a spiral arm

Question 6

The large flat part of a galaxy that rotates in a plane around its center

Answer 6

disk

Question 7

We cannot use star counting in the Galactic disk in order to locate its center because

Answer 7

we cannot observe stars in the disk except in our vicinity due to the effects of interstellar dust on starlight

Question 8

Gravitational lenses

Answer 8

All of the above

Question 9

Hubble constant gives us an approximate age of the universe of

Answer 9

12-15 billion years

Question 10

The local group of galaxies is a cluster of over _____ galaxies that includes the Milky Way Galaxy, the Andromeda galaxy, the two magellanic clouds, and numerous dwarf galaxies

Answer 10

54

Question 11

Olbers’ paradox is an argument showing that he sky in an infinite, static universe could not be dark

Answer 11

True

Question 12

Which of the following is true about the amounts of heavy chemical elements in the early universe

Answer 12

They were insignificant

Question 13

The small fluctuations that are observed in the CMB radiation are significant because

Answer 13

They show that the early universe was not completely homogeneous

Question 14

When we talk about “isotropy” in cosmology we mean that

Answer 14

The universe looks the same in any direction

Question 15

Dark energy (whatever it turns out to be) is slowing the expansion of the universe

Answer 15

False

Question 16

How many billions of stars are in the Milky Way Galaxy?

Answer 16

200

Question 17

What percentage of the universe is made up of Cold Dark Matter?

Answer 17

20

Question 18

Hubble divided spiral galaxies into two groups: ordinary spirals and ______ spirals.

Answer 18

Barred

Question 19

Most of the galaxies in existence are elliptical

Answer 19

True

Question 20

The Milky Way Galaxy is which type of galaxy?

Answer 20

Spiral

Question 21

We say that quasars, blazars and radio galaxies are really the same thing because

Answer 21

We can explain observations of these objects with a single model

Question 22

Observations show that clusters of galaxies are filled with

Answer 22

high temperature, low density gas

Question 23

Population II stars in our Galaxy are found mostly

Answer 23

in globular clusters

Question 24

According to the self-propagating star formation theory of galactic arms, the triggers that start the collapse of most interstellar clouds are nearby black holes

Answer 24

False

Question 25

Newton proposed that the universe was infinite because if it were not, gravity would cause it to collapse to its center

Answer 25

True