Astronomy 103 HW 10

1.

1 point

In the formation of our Galaxy, the ________ formed first.

spiral arms

planetary nebulae

globular clusters

galactic disk

galactic center

2.

1 point

What two observations allow us to calculate the Galaxy's mass?

the Sun's composition and luminosity

the Sun's mass and its age

the Sun's age and period of the Galactic Year

the Sun's orbital velocity and its distance from the Galactic Center

the Sun's mass and velocity in orbit of the Galactic Center

3.

1 point

In age, Population I stars are typically much ________ than those of Population II.

brighter

older

dimmer

younger

4.

1 point

The distance between adjacent galaxies in a typical cluster is about ________ times the size of a typical galaxy.

ten to twenty

a hundred

two or three

five or less

5.

1 point

A galaxy is at a distance of one billion light years. Which of the following is true?

We see what our galaxy will be like in one billion years.

We see the galaxy the way it was one billion years ago.

We have no knowledge of anything at that distance.

We see the galaxy the way it will be in one billion years.

We see the galaxy the way it was when the universe was one billion years old.

6.

1 point

Which of the following statements is FALSE about binary star systems?

Very different stars can be paired in a binary.

The masses of each star in a binary system cannot be found.

A binary system can be used to find the distance to both stars.

A binary system with a white dwarf can lead to a supernova.

The stars in a binary system can alternately eclipse each other.

7.

1 point

Interstellar gas is composed of:

only hydrogen

10% hydrogen, 90% helium by numbers of atoms.

some hydrogen, but mainly carbon dioxide.

90% hydrogen, 9% helium by weight.

8.

1 point

What effect do even thin clouds of dust have on light passing through them?

Even a little can completely block all light, such as the Horsehead Nebula.

It dims and reddens the light of all more distant stars.

Its motion causes the light of stars beyond to twinkle.

The light that passes through them is blue shifted due to the cloud's approach.

9.

1 point

Charles Messier mapped the night sky and identified many objects now known to be emission nebulae in his search for objects that might be confused with:

binary stars

white dwarfs

red giants

black holes

comets

10.

1 point

Most of the galaxies in the Local Group are:

small ellipticals like the companions to M31 in Andromeda.

small irregulars like the Magellanic Clouds.

small spirals like M33 and the LMC.

big spirals like our Galaxy and M31.

11.

1 point

All of the following are clusters of galaxies EXCEPT:

Shapley

The Local Group

Virgo

Coma

Andromeda

12.

1 point

A supernova that occurred 30,000 years ago in a galaxy 100,000 light years away will be observed on Earth:

70,000 years ago.

100,000 years ago.

100,000 years from now.

70,000 years from now.

30,000 years from now.

13.

1 point

Collisions between galaxies are thought to:

have stopped about 5 billion years ago

have never occurred

be extremely rare.

be commonplace.