Summer School Astronomy 8 & 15

Name:

Multiple Choice
Identify the choice that best completes the statement or answers the question.

The first scientific attempt to map the Milky Way galaxy

a.	showed that the sun was located near the edge of the galaxy.
b.	showed that the halo of the galaxy contained population II stars.
c.	showed that our galaxy contained spiral arms.
d.	used globular clusters to determine the location of the center of the galaxy.
e.	was completed by William and Caroline Herschel.

Herschel's grindstone and Kapteyn's star system were too small because

a.	they did not count the brightest stars.
b.	they did not study the southern sky.
c.	they did not have large enough telescopes.
d.	they only observed stars in the disk of the galaxy and not the halo.
e.	they did not know about interstellar dust clouds.

The chemical abundance of population I stars

a.	indicates that they were formed before the population II stars.
b.	indicates that the material they formed from had been enriched with material from supernovae.
c.	indicates that they contain very few heavy metals compared to halo stars.
d.	depends on the temperature of the star.
e.	depends on the mass of the star.

If the spiral density wave were the only thing producing spiral arms, it would be expected that

a.	all spiral arms would be dust free.
b.	all galaxies would have grand design spiral patterns.
c.	the Milky Way would be more massive than observed.
d.	the Milky Way wouldn't have any spiral arms.
e.	the halo component of the Milky way would show spiral arms as well.

Most of the energy emitted by the sun is generated in the

a.	corona.
b.	photosphere.
c.	chromosphere.
d.	core.

The sun's magnetic field is evident in the looped shapes of

a.	solar flares.
b.	sunspots.
c.	the corona.
d.	granules.
e.	solar prominences.

A filtergram is a photograph of the sun's surface made

a.	in a band of wavelengths in the infrared.
b.	in a band of wavelengths in the ultraviolet.
c.	using the Zeeman Effect.
d.	with only those photons emitted in a specific spectral line.
e.	none of the above

The ____ is (are) the hot gases that are the moving extension of the sun's corona.

a.	spicules
b.	prominences
c.	flares
d.	supergranules
e.	solar wind

Sunspots are dark because

a.	regions of the photosphere are obscured by material in the chromosphere.
b.	shock waves move through the photosphere.
c.	the sun rotates differentially.
d.	the strong magnetic field inhibits the currents of hot gas rising from below.
e.	they radiate their energy into space faster than the rest of the photosphere.

10.

The energy source at the center of our galaxy is called

a.	Cygnus X-1.
b.	the Orion arm.
c.	the sun.
d.	Sagittarius A*.

11.

The nuclear bulge of our galaxy

a.	contains stars that are primarily population I stars.
b.	contains relatively large amounts of gas and dust.
c.	contains stars primarily associated with the spherical component of our galaxy.
d.	contains stars primarily associated with the disk component of our galaxy.
e.	a, b and d

12.

High temperatures are required to get H nuclei to fuse because they ____ one another because of their ____ electric charges.

a.	attract, negative
b.	attract, positive
c.	repel, negative
d.	repel, positive

13.

The corona of the sun can be observed

a.	during a lunar eclipse.
b.	with a coronagraph.
c.	using filtergrams.
d.	a and b above
e.	with none of the above

14.

Nucleosynthesis

a.	is the process by which energy is produced at the center of the galaxy.
b.	is the process by which hydrogen and helium are converted into heavier elements.
c.	describes the structure of a globular cluster.
d.	describes how the magnetic field of the galaxy traps cosmic rays.
e.	describes the method by which neutral hydrogen produces 21 cm radiation.

15.

CO observations of the galaxy reveal

a.	the location of dense neutral hydrogen clouds.
b.	the location of population II stars.
c.	the location of population I stars.
d.	the location of the galactic corona.
e.	the location of giant molecular clouds.

16.

Population II stars

I.	are primarily found in the disk of the galaxy.
II.	contain more heavy metals than population I stars.
III.	are primarily old low mass stars.
IV.	are located in globular clusters.

a.	III & IV
b.	I & II
c.	II
d.	IV
e.	I, II, & III

17.

A(n) ____ is believed to occur when energy, stored in a twist in the solar magnetic field above a sunspot, is suddenly released.

a.	solar flare
b.	supergranule
c.	spicule
d.	coronal hole
e.	none of the above

18.

Radio maps of the spiral arms of our galaxy

a.	reveal that our galaxy is a grand design spiral.
b.	map the location of Hot O and B stars by the radio radiation they emit.
c.	reveal that the spiral arms are winding up and growing closer together.
d.	reveal that the sun is currently located in the center of a spiral arm.
e.	map the location of dense neutral hydrogen clouds.

19.

The traditional theory for the formation of the Milky Way Galaxy suggests that the galaxy formed

a.	as material accreted around a massive black hole currently at the center of our galaxy.
b.	from a large cloud of material that formed stars and star clusters and slowly flattened to a disk.
c.	from material that had been ejected in the violent explosion of a dying galaxy.
d.	as a result of mergers between several smaller groups of gas, dust, and stars.
e.	as two massive galaxies collided.

20.

Sunspots are known to be magnetic phenomena because

a.	Doppler shifts in spectral lines are observed.
b.	the Zeeman Effect is observed in sunspots.
c.	collisional broadening is observed in spectral lines.
d.	infrared observations indicate that the sunspots are cooler than their surroundings.
e.	observations during eclipses reveal a very extensive photosphere.

21.

Neutrinos are created in reaction in the ____ of the sun.

a.	corona
b.	chromosphere
c.	photosphere
d.	core

22.

The mass of the black hole at the center of our galaxy can be estimated using the ____ of a star orbiting it.

a.	semi-major axis
b.	orbital perio
c.	Both answers a and b.
d.	Neither answer a or b.

23.

The center of our galaxy lies in the direction of the constellation of

a.	Ursa Minor.
b.	Ursa Major.
c.	Sagittarius.
d.	Orion.
e.	Monoceros.

24.

Halo stars located in the disk are easy to detect because they

a.	are the only low mass stars in the disk.
b.	are only found in globular clusters.
c.	are primarily O and B supergiants.
d.	move at an angle across the disk.
e.	emit cosmic rays.

25.

The centers of granules

a.	are hot material rising to the photosphere from below.
b.	are cool material falling from the photosphere to the regions below.
c.	are fainter and hotter than their surroundings.
d.	are brighter and cooler than their surroundings.
e.	show strong Zeeman effects.

26.

A several million solar mass ____ is thought to be at the center of our galaxy.

a.	spiral arm
b.	globular cluster
c.	planet
d.	black hole

27.

Modern astronomers suspect the corona is heated by

a.	shock waves rising from below the photosphere.
b.	the solar wind.
c.	the solar magnetic field.
d.	all of these
e.	none of these

28.

The photosphere is very thin because

a.	the temperature of the photosphere increases rapidly from its base to its outer edge.
b.	the gas bubbles that form the granulation pattern cannot travel very far.
c.	the magnetic field compresses the photosphere.
d.	the H^- ion is a very good absorber of photons and causes the gas of the photosphere to be opaque.
e.	the sun rotates differentially.

29.

Fusion is promoted in the core of the sun by the ____ there.

a.	low temperature and low density
b.	high temperature and high density
c.	low temperature and high density
d.	high termperature and low density

30.

Good spiral tracers are all

I.	very old.
II.	very young.
III.	very luminous.
IV.	moving with large radial velocities.

a.	I & III
b.	I & IV
c.	II & III
d.	II & IV
e.	I, III, & IV

31.

Most of the light we see coming from the sun originates in the

a.	chromosphere.
b.	photosphere.
c.	corona.
d.	sunspots.
e.	magnetic field.

32.

Which of the following is not a characteristic of the stars of the disk component of our galaxy?

a.	circular orbits
b.	randomly inclined orbits
c.	higher metal abundance
d.	young stars
e.	star formation regions

33.

The energy source at the center of our galaxy

a.	is not visible at optical wavelengths.
b.	produces gamma rays.
c.	must be less than 10 AU in diameter.
d.	all of the above
e.	none of the above

34.

____ occur(s) because photons we receive from the edge of the solar disk are emitted further from the base of the photosphere than the photons we receive from the center of the solar disk.

a.	The Zeeman Effect
b.	Sunspots
c.	Solar flares
d.	Solar prominences
e.	Limb darkening

35.

Younger stars have more heavy elements because

a.	old stars destroy heavy elements as they age.
b.	young stars burn their nuclear fuels faster.
c.	heavy elements were made in previous generations of stars.
d.	all of the above
e.	heavy elements haven't had time to settle to the core of these younger stars.

36.

The energy generated by the sun is released by the ____ nuclei to make ____ nuclei.

a.	fusion of H nuclei, He
b.	fusion of He nuclei, H
c.	fission of H nuclei, He
d.	fission of He nuclei, H

37.

Granulation is caused by

a.	sunspots.
b.	rising gas below the photosphere.
c.	shock waves in the corona.
d.	the solar wind flowing away from the corona.
e.	the heating in the chromosphere.

38.

A group of 10 to 100 stars that formed at the same time but are so widely scattered in space their mutual gravity cannot hold them together is called

a.	a globular cluster.
b.	an open cluster.
c.	an association.
d.	a spherical component.
e.	an accretion disk.

39.

The age of the Milky Way galaxy has been estimated to be at least 13 billion years based on

a.	observations of globular clusters.
b.	observations of open clusters.
c.	21-cm radiation from H I regions.
d.	the rotation curve of the galaxy.
e.	the energy produced by Sagittarius A*.

40.

The variation in the strength of the calcium H and K emission from sun-like stars implies that these stars

a.	probably have very extended coronae.
b.	probably have a magnetic cycle similar to the sun's.
c.	do not rotate differentially.
d.	may have planets that orbit them.
e.	probably have supergranules and spicules.

True/False
Indicate whether the statement is true or false.

41.

Solar flares have no known effect on the Earth.

42.

The corona is heated by the solar magnetic field.

43.

The Zeeman Effect shows that sunspots contain magnetic fields.

44.

A giant fusion power reactor has been supplying all natural energy to the United States since 1776.

45.

The disk of the galaxy is older than the halo.

46.

An older theory suggested that the corona was heated by shock waves from the convection zone.

47.

There is only one form of neutrino.

48.

Spiral tracers tend to be old, luminous stars.

49.

Giant molecular cloud complexes are located in spiral arms.

50.

Most of the visible light from the sun originates in the photosphere.