Instructions: For multiple choice questions, simply circle the letter of the one best answer. Each of the multiple-choice questions is worth 1 points. For the essay questions write your essays in the test booklet. Each essay question is worth 10 points. The combined total of all questions is 120 points. The final exam score will be scaled for a maximum of 200 points and then added with the mid-term score (a maximum of 100 points) to give a final course score with a maximum of 300 points.

1. the Sun being closer to the Earth at certain times of the year
2. the tilt of the plane of the Moon's orbit to the plane of the Earth's orbit
3. the inclination of the rotation axis of the Earth to its orbital plane
4. the motion of the vernal equinox along the equator

1. Science is based fundamentally on the belief that the universe is comprehensible. In addition, a scientific theory must

1. Make testable predictions
2. Be verified by observations and experiments
3. Satisfy aesthetic desires
4. Both a. and b.

1. If the nearest star is 4.2 light years from the Solar System, then

1. the light we see left the star 4.2 years ago
2. the star must be in another galaxy
3. the star is 4.2 million AU from us
4. the star must have formed 4.2 billion years ago

1. Which of the following is FALSE?

1. Sidereal days are approximately 24 hours and 4 minutes
2. Solar days are 24 hours
3. Sidereal days are based on the apparent rotation period of the celestial sphere
4. Solar days are based on the apparent rotation period of the sun
5. Solar days are longer than sidereal days

1. There are two ocean tides each day and they are cause by

1. Gravity locking of the Moon’s orbital period with its rotation period
2. Moon’s gravity pulling the oceans first towards the moon during the day and away from the moon during the night
3. Earth’s rotation through the world’s oceans which have been made oblate by the moon’s gravity
4. High tide caused by the Moon’s gravity and low tide caused by the Sun’s gravity

1. Copernicus is famous for leading a revolution in human thought about the universe; the title (translated to english) of his famous work was

1. Almagest
2. Sidereal Messenger
3. Principia
4. Astrophysics Journal
5. The Revolution of the Heavenly Orbs

1. Galileo was the first person to use this instrument for astronomical observations:

1. the abacus
2. the sextant
3. the telescope
4. the compass

1. Kepler's first law says that planetary orbits are ellipses with the Sun at one focus. What is located at the other focus?

1. the Moon
2. the planet
3. nothing
4. a comet

1. According to Newton’s second law of motion, a force must be acting whenever

1. an object’s mass changes
2. an object moves with constant speed
3. time passes
4. an object’s state of motion changes, i.e. it accelerates
5. none of the above

1. Einstein’s theory of gravity replaced Newton’s as a more accurate description of gravitational phenomenon. Which of the following would be an apt description of Einstein’s theory of gravity?

1. Gravity as curvature of spacetime
2. The Special Theory of Relativity
3. Quantum Gravity
4. A pound of feathers falls at the same rate as a pound of lead

1. Outside the Earth's atmosphere, the scintillation of stars

1. is far more pronounced than from Earth's surface
2. is about the same as from Earth's surface
3. is less pronounced than from Earth's surface
4. does not happen

1. The two ranges of electromagnetic radiation for which the Earth’s atmosphere is reasonably transparent are

1. visible and far infrared radiation
2. X-rays and visible radiation
3. UV and radio waves
4. visible and radio waves
5. none of the above

1. Which is the correct ordering of the electromagnetic spectrum from long to short wavelength?

1. Radio, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays
2. Visible, ultraviolet, infrared, x-rays, microwaves, gamma rays, radio
3. Gamma rays, x-rays, ultraviolet, visible, infrared, microwaves, radio
4. Ultraviolet, gamma rays, visible, x-rays, radio, infrared, microwave
5. none of the above

1. For a star moving away from the Solar System, the color of the radiation will be Doppler shifted, that is

1. reversed so that red wavelengths will become blue and blue wavelengths will become red ones
2. blueshifted, or shifted toward shorter wavelengths
3. unaffected since the Solar System is moving also
4. redshifted, or shifted toward longer wavelengths
5. none of the above

1. The process of removing an electron from an atom is known as

1. Ionization
2. Doppler effect
3. random thermal collision
4. a redshift
5. none of the above

1. A common feature in the absorption spectra of starlight, and with frequencies in the visible light range, is the ___________ of the Hydrogen atom

1. Lyman series
2. Balmer series
3. Paschen series
4. K lines
5. None of the above

1. Comets are believed to originate in

1. Primordial debris from the Jovian system ejected by Jupiter’s moons
2. The asteroid belt
3. Neighboring stars systems
4. The Kuiper Belt and the Oort cloud at the outer edge of our solar system

1. We expect that the existence of planets around other star is likely because

1. Since they exist around the sun, they may exist elsewhere
2. We observe Doppler shifted spectra from nearby stars indicating they have a Jupiter-sized planet in orbit around them
3. We observe infrared images showing large, dust disks around nearby stars
4. All of the above

1. Which of the Moons of Jupiter is characterized by an exceptionally smooth, icy surface, few craters, and many streaks and cracks?

1. Io
2. Europa
3. Callisto
4. Ganymede

1. What is the source of Jupiter's intense magnetic field?

1. Electric currents in Jupiter's metallic hydrogen mantle
2. Electric currents in Jupiter's molten rocky core
3. A permanently magnetized iron core
4. Electric currents in ionized layers of Jupiter's atmosphere.

21. The temperature of the Sun’s surface, the photosphere, is approximately

1. 580^o K
2. 5,800^o K
3. 58,000^o K
4. 580,000^o K

21. Which of the following statements gives the approximate chemical composition of the Sun?

1. The Sun is composed primarily of iron and the elements around iron in the periodic table.
2. The most abundant elements in the Sun are carbon, nitrogen, oxygen, and silicon.
3. The most abundant element in the Sun is calcium as evidenced by the strong H and K lines of singly ionized calcium in the solar photospheric spectrum.
4. The most abundant elements in the Sun are hydrogen and helium.
5. The primary constituents of the Sun are oxygen, silicon, and aluminum

21. A periodic red-shifting and blue-shifting of the wavelengths of the absorption lines in the spectrum of a star suggests that it is

1. gaining mass at the expense of other stars
2. a member of a binary star system
3. moving rapidly toward the observer
4. getting hotter
5. none of the above

21. If we compute masses and luminosity for many stars and plot the results, which of the following is true?

1. L=M^3.5
2. L=1/M
3. Red giants fit the plotted curve very well
4. Main sequence stars don’t fit the curve very well
5. None of the above

21. The interstellar medium is comprised and gas and dust. The most abundant component is

3. Carbon
4. Silicates
5. None of the above

2. Ionized hydrogen atoms occasionally capture free electrons, which cascade down to the lower energy levels of the neutral hydrogen atom, giving off a pinkish glow of the Balmer series.
3. Gas and dust preferentially scattering blue light more than red light, giving a bluish tint.
4. Dense clouds of dust occluding the light of stars hidden within.
5. All of the above

27. Which are components of the interstellar nebula

1. small neutral HI clouds (dark nebulae)
2. warm inter-cloud media (HII emission nebulae)
3. molecular clouds
4. coronal gas
5. All the above

27. Reflection nebulae are characterized by

1. Carbon monoxide (CO) molecules absorb electromagnetic energy at discrete spectral lines.
2. Ionized hydrogen atoms occasionally capture free electrons, which cascade down to the lower energy levels of the neutral hydrogen atom, giving off a pinkish glow of the Balmer series.
3. Gas and dust preferentially scattering blue light more than red light, giving a bluish tint.
4. Dense clouds of dust occluding the light of stars hidden within.
5. All of the above

29. Occasionally, the spin of an electron in a hydrogen atom flips from parallel to anti-parallel, emitting a photon with a wavelength of 21 cm in the process. Clouds of cold hydrogen in the interstellar medium then emit a measurable signal of 21 cm radiation which we can detect on earth as

a. High-energy gamma and X-rays

b. UV radiation

c. Visible light

d. Infrared radiation

e. Radio waves

30. Which one is NOT a force opposing gravitational collapse of a gas cloud into a star?

1. Gas pressure
2. Interstellar magnetic fields
3. Angular momentum
4. Infrared radiation

33. The energy from thermonuclear fusion, such as the burning of two hydrogen atoms to form a helium atom, generates energy according to which fundamental equation?

1. None of the above

35. All the stars that are in the hydrogen-burning phase of their lives

1. are located well above the main sequence
2. can be found anywhere on the H-R diagram
3. are located in the white dwarf region
4. are located on the main sequence
5. can be found in the red giant region

35. For stars in general, successive stages of thermonuclear burning

1. are viable energy sources for shorter and shorter periods of time as synthesis proceeds toward heavier elements
2. are only possible if gravitational contraction can raise core temperatures higher and higher
3. use the end product or "ash" of the preceding stage as the fuel
4. all of the above

35. A stellar structure model is

1. another name for the color index of a star
2. a small, high-temperature gas structure created in a laboratory that can reproduce many of the properties of stars, such as thermonuclear fusion of hydrogen
3. a mathematical model produced by calculations on a high-speed computer which balance temperature, pressure and energy transport throughout a star’s interior

4. pictorial concept used to aid in the discussion of stellar evolution

40. After the Sun has completed its red-giant phase, the Sun

1. will go through a supernova outburst and end its existence as a white dwarf
2. will contract and move into the blue supergiant region where it will burn carbon and other exotic nuclear fuels
3. will probably go through the ejection of its outer envelope as a planetary nebula leaving a white dwarf
4. will become a neutron star emitting an intense beam of radiation that will sweep around the sky as the Sun rotates
5. none of the above

40. The type of star that is supported against its own weight by the pressure of degenerate electrons is called a

1. neutron star
2. red giant star
3. white dwarf
4. supergiant star
5. main-sequence star

40. Which of the following is true about the last stages of stellar evolution?

1. For white dwarfs or neutron stars, their interiors are composed, respectively, of a degenerate gas of electrons or neutrons, which provides the pressure necessary to hold up the weight of the overlying layers making them indefinitely stable.
2. Low-mass stars usually end their lives as white dwarfs.
3. Astronomers expect that stellar-size black holes can best be observed as companions in a binary system where the other star is a normal star, such as a blue supergiant, which provides mass to feed the accretion disk of the black hole
4. all of the above
5. none of the above

40. The elements beyond iron in the periodic table are probably produced during which phase in stellar evolution?

1. pre-main sequence contraction
2. main-sequence evolution
3. red-giant evolution
4. white dwarf stage
5. supernova outburst by massive stars

40. Carl Sagan, who was a famous popularist of science and astronomy in the 70’s and 80’s, used to say, "we are made of star stuff." This was based on the fact that

1. The heavy elements found in the solar system had to be made in the cores of massive stars and supernova explosions, thus our solar system formed from the remains of massive stars that existed billions of years ago
2. The atoms that make up our bodies are the same as the atoms found in all stars
3. As the sun evolves to become a red giant, it will consume the earth in its outer envelope, thereby making us all part of a star
4. The connection of all things through general relativity and quantum mechanics means all things are unified

40. Pulsars are probably

1. two white dwarfs in a binary system
2. rotating neutron stars
3. collapsing black holes
4. explosive main-sequence stars
5. none of the above

1. Einstein's development of the principle of equivalence, that a gravitational force can be replaced by an inertial force without any change in the physical activity, was important in leading his thoughts in the direction of the theory of general relativity.
2. The general theory of relativity describes gravity entirely in terms of the geometry or curvature of space and time.
3. Einstein's theory of general relativity is an alternative theory for gravity.
4. all of the above.
5. None of the above.

1. the typical radius for star clusters
2. the radius of the visible universe
3. the radius of the event horizon for black holes
4. the typical radius for spiral galaxies
5. none of the above

48. The mass of a black hole produced by the collapse of a star

1. a member near the spiral arms of the Galaxy
2. a member of the disk population stars
3. a member of the nuclear bulge population of the nucleus
4. a member of the halo stars of the Galaxy
5. none of the above

1. have great chains of interstellar clouds
2. represent the most active location of star formation
3. possess slightly different spiral-arm patterns depending upon whether they are determined from H II regions caused by brightly shining O and B type stars or determined from 21-centimeter radiation from atomic hydrogen, etc.
4. all of the above
5. none of the above

1. Models of galaxy formation
2. Red-shift of stars in nuclear bulge
3. Red-shift of stars in globular clusters
4. H-R diagram turn-off points of open clusters and globular clusters
5. None of the above

1. Population I stars are metal poor
2. Population II stars are metal rich
3. The Sun is a population I star
4. Population II stars formed from the remains of exploded massive stars
5. None of the above

1. postulates spiral arms are dynamically stable regions of compression which progress slowly about the galactic center
2. gas clouds revolve about the galactic center more quickly and collide with the compression regions
3. sudden compression of gas cloud leads to star formation
4. supernovae in the star forming region can lead to a self-sustaining chain of new star formation
5. None of the above

55. Which of the following is thought to be correct concerning galaxies?

1. The spectrum of a galaxy has the general appearance of being the composite of the spectra of a large number of stars.
2. The velocity-distance relation exhibited by galaxies in which their blueshifts (which are used to obtain their velocities) are inversely proportional to their distances squared.
3. all of the above
4. none of the above

55. The Hubble classification for a spiral galaxy with a prominent central bulge and tightly-wound spiral arms is

1. Sa
2. E0
3. Sc
4. Sba
5. none of the above

55. The majority of the luminosity of a Galaxy is provided by

1. primarily the red and blue supergiants
2. supernovas
3. O and B stars, since they are intrinsically so luminous
4. red and white dwarfs

55. The redshift of the absorption lines in the spectra of distant galaxies discovered by Edwin Hubble is due to the

1. "tiredness" of light traveling over the immense distances of the universe
2. Doppler shifting of light from galaxies all flying apart from each other
3. reddening of light moving through intergalactic space by intergalactic dust
4. gravitational redshift of thousands of galaxies falling into black holes
5. none of the above

1. None
2. One, faintly. The Andromeda galaxy
3. 42
4. Millions
5. Billions

1. Enormous luminosity
2. Very distant objects
3. Are always isolated from other galaxies
4. Very strongly redshifted

1. For high values of redshift, the Doppler shift and the recession velocity are also both large
2. For high values of redshift, the Doppler shift is high but the recession velocity is low
3. For high values of redshift, the Doppler shift is low and the recession velocity is high
4. For high values of redshift, the Doppler shift and the recession velocity are both low

1. The AGNs we see today have a lookback time approaching the early ages of the universe when the density of galaxies was much higher and collisions more common
2. The high luminosities of nearby quasars are obscured by intergalactic dust surrounding the Milky Way
3. Since the redshift from nearby galaxies is so slight, the computation of the distance modulus formula underestimates their luminosity
4. None of the above

65. The approximate age of the universe as estimated from the current value of Hubble's constant is

1. 50-60 billion years
2. 25-30 billion years
3. 10-15 billion years
4. 1-2 billion years
5. none of the above

1. In an expanding universe objects may lie beyond our visible horizon so that at some point in the future they will enter our horizon.
2. The time at which space began expanding in the universe is called the big bang.
3. Because the universe is homogeneous on the largest scales, the curvature of space globally is uniform, whether it is closed, flat, or open.
4. all of the above
5. none of the above

1. The universe described by general relativity and the big bang theory has no center and no edge.
2. It is through the theory of general relativity that we hope to understand why the universe started off so very flat and smooth in order that it possess those properties now, since general relativity is a complete theory whose mathematical laws were in operation before, during, and after the big bang.
3. According to Einstein's concept of space and time, there is space beyond the universe, and there is time before and after the universe, i.e. space and time are absolutes independent of the universe.
4. all of the above

1. Homogeneity—matter is uniformly spread throughout space
2. Isotropy—the universe looks the same in all directions
3. All the above
4. None of the above

1. Our solar system
2. Spectra of stars
3. Meteorite and comet samples
4. Giant molecular clouds
5. All of the above

1. Less than 1
2. Approximately 10
3. Approximately 10,000
4. Approximately one million

Essay Question. Choose ONE of the following two questions and write a short essay in the test booklet below. Be concise, but use enough detail, terminology, and quantitative information to provide thorough answer. Draw figures where appropriate. A one page answer should suffice, but a second page is provided if needed. (10 points)

E1. Describe the interior layers (structure) of the Sun, how energy is generated, and how the energy makes its way to the outer layers of the Sun to be radiated into space

E2. Explain how stars are classified by the Hertzsprung-Russell diagram? Draw a picture of an HR diagram and locate where the different types of stars are located.

Essay Question. Choose ONE of the following two questions and write a short essay in the test booklet below. Be concise, but use enough detail, terminology, and quantitative information to provide thorough answer. Draw figures where appropriate. A one page answer should suffice, but a second page is provided if needed. (10 points)

E3. Describe the formation of stars within a cluster and explain a method for estimating the age of the cluster.

E4. Describe the evolution of main sequence star with a mass of 20 M_Sun. Describe the various phases of energy generation, migration off the main sequence, and the eventual fate of the star to include what forces are at balance throughout.

Essay Question. Choose ONE of the following two questions and write a short essay in the test booklet below. Be concise, but use enough detail, terminology, and quantitative information to provide thorough answer. Draw figures where appropriate. A one page answer should suffice, but a second page is provided if needed. (10 points)

E5. Describe what a black hole is. Do we have any evidence that they exist in nature?

or

E6. Describe our Milky Way galaxy and explain what observations were used to determine its structure, size, and mass.