Astro-110 Section-2
PRACTICE FINAL Exam
A suggestion on taking the exam. Don’t dwell on a single
problem. Do the questions you know first, and then come
back to the ones that give you trouble. There are several
questions that are a bit harder than the rest and these
may require a bit more effort. Save these for last.
Multiple Choice questions (CIRCLE THE CORRECT
ANSWER).
1. Which of the following distance measuring techniques would you use to measure the distance to
the Andromeda galaxy (approx 1 Mpc away)?
(a) parallax
(b) Kepler’s third law
(c) Tully-Fisher relation
(d) cepheid variable stars
(e) measure the angular size of stars and us the
small angle approximation
2. Where is our solar system located in our galaxy?
(a) core
(b) bulge
(c) halo
(d) disk
(e) nucleus
PRACTICE FINAL Exam
4. The burst of exponential expansion during the earliest phase of the Big Bang is known as
(a) inflation.
(b) steady state.
(c) implosion.
(d) explosion.
(e) impossible.
5. The distances to quasars are measured using
(a) parallax.
(b) cepheid variable stars.
(c) radar.
(d) redshift and Hubble’s law.
(e) the Tully-Fisher relation.
6. We think the universe began with the Big Bang approximately how long ago?
(a) 1.4 × 1022 yrs.
(b) 1.4 × 1010 yrs.
(c) 1.4 × 103 yrs.
(d) 1.4 × 10−6 yrs.
(e) 1.4 × 106 yrs.
7. When the expanding fireball of the Big Bang cooled
to approximately 4000K, electrons and protons
combined to form neutral atomic hydrogen. What
is the significance of this event?
3. If the nucleus of the Milky Way contains a massive
black hole, we can expect
(a) The universe started expanding according to
Hubble’s law.
(a) that galaxy to destroy itself in a tremendous
supernova explosion.
(b) The present laws of physics began to apply for
the first time.
(b) that the black hole will eventually swallow
most of the galaxy including our solar system.
(c) Nuclear fusion was possible for the first time.
(c) that someday our galaxy may erupt as an AGN
if enough material happens to fall into the
black hole.
(d) The universe became transparent to light for
the first time.
(e) Stars formed for the first time.
(d) that stars in the nucleus that orbit too close
to the black hole will be flung into the spiral
arms.
8. Why can we not see the center of our galaxy using
visible light?
(e) that that black hole will accelerate the rotation of our galaxy, spinning it up to enormous
rotational velocities.
(b) Light cannot escape the gravitational pull of
the black hole in the center of our galaxy.
(a) It is too far away.
(c) The center is obscured by gas and dust.
Astro-110 Section-2
(d) The center does not emit visible light - just
x-rays.
(e) The center is moving away from us too fast.
9. Which of the following provides the best evidence
that the universe began with a Big Bang?
(a) the ages of globular clusters.
(b) quasars.
(c) neutron stars.
(d) gravitational lensing.
(e) the Cosmic Microwave Background.
10. Why is the study of the structure of our galaxy more
difficult than the study of the structure of distant
galaxies?
(a) We are located in our galaxy and cannot view
it from afar.
(b) The center of our galaxy is only visible from
the southern hemisphere.
(c) Our star is orbiting the center of the galaxy,
and its motion confuses the interpretation of
the motions of other objects.
(d) Our Earth is orbiting the Sun so we cannot see
our galaxy except during certain parts of the
year.
(e) None of the above.
11. The twin of our galaxy is the nearby Andromeda
galaxy. What kind of galaxy is it?
(a) giant elliptical.
(b) dwarf elliptical.
(c) irregular.
(d) Hubble sequence.
(e) spiral.
12. The solar system is believed to have formed approximately how long ago?
(a) 4.5 billion years.
(b) 1 billion years.
(c) 5000 years.
(d) 45 billion years.
(e) 12 billion years.
PRACTICE FINAL Exam
13. Nearly all the hydrogen and helium in the universe
were formed
(a) in stars.
(b) in the early universe during the phase of nucleosynthesis.
(c) in the cores of large galaxies.
(d) in the interstellar medium.
(e) in jets emerging from active galaxies.
14. Which of the following is the best evidence that the
universe is expanding?
(a) the Milky-Way and the Andromeda galaxy are
moving toward each other.
(b) our galaxy is traveling toward the Virgo cluster.
(c) gravitational lensing by clusters of galaxies.
(d) the redshift and blue shift of spectral lines in
binary star systems.
(e) external galaxy redshifts increase proportional
to the distance to the galaxy.
15. Which of the following provides some of the best
evidence for the existence of dark matter?
(a) Flat rotation curves in the outskirts of spiral
galaxies.
(b) Gravitational lensing by clusters of galaxies.
(c) Orbits and motions of galaxies in large clusters.
(d) Strong gravitational lensing by individual galaxies.
(e) All of the above.
16. Current observational evidence on the expansion of
the universe indicates
(a) the universe will expand for another 5 billion
years, gradually slowing down, and then it will
turn around and re-collapse in a Big Crunch.
(b) the universe will continue to expand forever.
(c) the universe will cease to expand once all the
stars use up their nuclear fuel.
(d) the cosmic microwave background is gradually
becoming warmer.
(e) that if we find out what dark matter is made
of, there might be enough of it to halt the expansion.
Astro-110 Section-2
17. In the search for signals from an extraterrestrial civilization, what region of the electromagnetic spectrum is expected to be the most fruitful?
(a) x-ray.
(b) ultraviolet.
(c) gamma-ray.
(d) radio.
(e) infrared.
18. Which of the following solar-system objects is most
likely to harbor life?
(a) Uranus.
(b) Mercury.
(c) The moon.
(d) Europa.
(e) Pluto.
19. Which of the following is an example of gravitational
lensing?
(a) Multiple images of quasars.
(b) Arcs in clusters of galaxies.
(c) The MACHO experiment that looked for light
variations of stars in the Large Magellanic
Cloud due to intervening matter in our galactic
halo.
(d) Both a and b.
(e) a, b and c.
20. Dark matter
(a) is found only in large clusters of galaxies.
(b) is likely made up of normal material that is
very dark.
(c) plays an important role in evolution of stars.
(d) triggers the explosion of a supernova.
(e) may be made of some as-yet-undetected, weaklyinteracting particle that was produced in large
numbers during the Big Bang.
21. What is the physical reason why spectral lines are
redshifted as objects move away from us?
(a) Doppler effect.
(b) Gravitational lensing.
PRACTICE FINAL Exam
(c) General Relativity.
(d) Strong nuclear force.
(e) Kepler’s third law.
22. What is the best-accepted model for the energy production in active galactic nuclei (AGN)?
(a) Supernova explosions in the galaxy core.
(b) Accretion of material onto a supermassive
black hole.
(c) Gravitational lensing by a supermassive black
hole in the galaxy nucleus.
(d) Matter/anti-matter annihilation in the center
of the active galaxy.
(e) None of the above.
23. What features of the Cosmic Microwave Background are most significant to cosmologists?
(a) The dipole anisotropy in the microwave background is due to our doppler motion with respect to the microwave photons.
(b) Tiny fluctuations in the uniformity of the microwave background give clues about the density perturbations in the early universe that
eventually led to the formation of the structure we now see.
(c) The spectrum of the microwave background indicates it is a nearly-perfect blackbody with a
present temperature of 2.7K.
(d) The microwave background provides a laboratory for measuring the mass of the neutrino.
(e) Both b and c.
24. Clusters of galaxies
(a) contain hundreds to thousands of galaxies.
(b) are filled with hot, x-ray emitting gas that has
as much mass as the visible galaxies.
(c) show gravitational lensing.
(d) have mass-to-light ratios of several hundred.
(e) all of the above.
25. Observations as well as computer numerical simulations show that the large scale structure of the
universe is
(a) homeogeneous and isotropic on Mpc scales.
Astro-110 Section-2
(b) difficult to measure and simulate without a
quantum theory of gravity.
(c) boring.
(d) clumpy, with galaxies confined to large clusters.
(e) web-like, with filaments, sheets, clusters and
voids.
26. The study of high redshift supernovae has revolutionized modern cosmology by
(a) indicating the expansion of the universe is accelerating.
(b) showing how recycled material is spread into
the interstellar medium.
(c) indicating that the universe is closed.
(d) illustrating the complexities of the late stages
of stellar evolution.
(e) showing the Big Bang theory to be incorrect.
27. About 25% of the matter in the Milky Way is helium. This figure is
(a) what is expected if the universe started with a
big bang.
(b) is one of the unsolved mysteries of modern astronomy.
(c) what is expected to be produced from sunernovae in the galaxy.
(d) the same as the helium percentage in the
Earth’s atmosphere.
(e) what is expected from fusion of H to He in the
cores of stars.
28. Which of the following is true concerning the search
for planets outside of our solar system?
(a) Astronomers have discovered no planets other
than those in our solar system.
(b) Over 100 extra-solar planets found around
nearby stars. Most are Jupiter-sized objects.
(c) A few Jupiter-sized extra-solar planets have
been found, but they are very rare.
(d) A large number of Earth-sized extra-solar planets have been found. Expeditions to them are
being planned.
(e) Planets exist around all stars.
PRACTICE FINAL Exam
29. Evidence now shows that the expansion of the universe may be accelerating. This acceleration is attributed to
(a) dark matter.
(b) neutrinos.
(c) dark energy.
(d) supernova explosions.
(e) primordial black holes.