ASTR 204 Home
What are Gamma Ray Bursts?
How were Gamma Ray Bursts discovered?
How was it determined that Gamma Ray Burst's do not lie in the Milky Way's disk?
How was it determined that Gamma Ray Burst's are far away?
What is a redshift?
How do we know that the Universe is expanding?
What does the fact that Gamma Ray Bursts are far away imply about the amount of energy that they produce?
What is one possible explanation for Gamma Ray Bursts? Can this
mechanism explain all Gamma Ray Bursts?
What was the Shapley-Curtis Debate about?
What positions did Shapley take?
What positions did Curtis take?
What are Cepheid variables and what is their significance?
What arguments did Shapley use to suggest 1) the Sun was far from the Galaxy's center, 2) the Milky Way
was larger than previously believed, and 3) the spiral nebulae lay within our Galaxy?
What arguments did Curtis use to suggest 1) the Sun was at the center of a relatively small
Milky Way and 2) the spiral nebulae are galaxies beyond our own?
How did Edwin Hubble help to resolve the debate?
On which debate points was Shapley correct?
On which debate points was Curtis correct?
What is the current picture we have about the size and structure of the Milky Way and of
the other spiral nebulae?
What is the ``K-T Boundary'' and what is its significance?
What are foraminifera and what are their significance?
What is a dinosaur?
What are some of the reasons suggested for the disappearance of the dinosaurs?
Why is it so difficult to establish what killed the dinosaurs?
What is the scientific method?
What attributes does a really successful theory of dinosaur extinction require?
What is paleontology?
What is the impact theory of dino extinction and who discovered this theory?
What are some types of objects that may have caused the impact?
What is a comet, asteroid, meteor?
What are some of the reasons we think that impacts are common in the Solar System?
Why would an impact cause damage to the Earth?
How do we estimate how much damage is caused by an impact?
What are the predicted environmental effects (local and global) of an impact of a large, fast moving object on Earth?
What is the Greenhouse Effect?
What is Nuclear Winter, at least as applied to the death of the dinosaurs?
What are the specific predictions of the impact theory?
What is the evidence to date in support of the impact theory?
What is the iridium anomaly and its significance?
What are impact markers (spherules, shocked quartz, tektites) and their significance?
How would you estimate how often a species-destroying object impacts with the Earth?
What is the significance of Chicxulub?
What are some of the weaknesses of the impact theory?
What is the volcano-greenhouse theory?
What are the Deccan Traps and what is their significance?
What are hot spots and mantle plumes?
How do people think that the Hawaiian islands formed?
How might volcanic eruptions have killed the dinosaurs?
What are the consequences of increasing the CO2 in the Earth's atmosphere?
What are the strengths of the volcano-greenhouse theory?
What are the weaknesses of the volcano-greenhouse theory?
What do astronomers mean when they say dark matter?
In general, what are the two ways that dark matter can be detected (on other words, how does
dark matter affect the motions of objects and the path of light)?
How was dark matter discovered and by whom?
What is a cluster of galaxies?
What is a gravitational lens and how does it work?
What do you observe if you take a picture of a gravitational lens and why?
What is the rotation curve of a galaxy?
How do clusters of galaxies, rotation curves of individual galaxies, and gravitational lenses (either
involving individual galaxies or clusters of galaxies as the lens) tell us about dark matter?
In what other ways could you use a telescope to determine if dark matter was present in the Universe?
How was Neptune discovered?
What is the precession of the perihelion of Mercury and what is its significance?
What important lesson can we learn about the dark matter problem
from the discovery of Neptune and the precession of the perihelion of Mercury?
What is an alternate explanation for the effects normally attributed to dark matter?
What is the significance of dark matter for the fate of the Universe?
What are the Big Bang, Big Crunch, Big Rip, Hubble's Constant, Omega0, matter, and the dark energy?
What is a mass-to-light (M/L) ratio? What is M/L for galaxies, for clusters of galaxies, for the nearby
Universe?
How does M/L relate to Omega0, matter? What must Omega0, matter be to cause a Big Crunch (in the absence of dark energy)?
To what M/L does this Omega0, matter value correspond?
What are bulk flows and what is their significance?
How would you determine the amount of dark matter in the halo of a galaxy out beyond the visible stars
of that galaxy?
How would you estimate the mass density of the Universe?
What are some of the uncertainties in estimating the mass density of the Universe?
What are some of the ways that astronomers estimate the mass of clusters of galaxies?
If bulk flow measurements suggest that M/L ~ 500-600 (Omega0, matter ~ 0.3-0.4), and
cluster mass measurements (on somewhat smaller scales) give only
that M/L ~ 200-400,
where might the additional mass lie?
What are low surface brightness galaxies and their significance?
What are quasars?
What is the Lyman-alpha forest and its significance?
What is baryonic dark matter and what are the possible components?
What is non-baryonic dark matter and what are the possible components?
What are black holes, neutron stars, white dwarfs, and brown dwarfs?
What are WIMPS?
What are MACHOS and how are they detected?
What are neutrinos, where do they come from, and how are they detected?
What is the evidence for non-baryonic dark matter?
What is the evidence for baryonic dark matter?
What is Big Bang nucleosynthesis and its significance?
What are some pieces of evidence for the Big Bang?
Why did astronomers eventually rule out the possibility that all elements in the Universe were produced
either in stellar interiors or during supernova explosions?
What is a supernova?
What is the current theory as to how the elements (light and heavy) originated?
Why does nucleosynthesis tell us about the density of baryons (mass of baryons/volume of the Universe) today?
Why do nucleosynthesis predictions suggest that non-baryonic dark matter exists?
What are some of the problems inherent in assuming that a lot of dark matter is non-baryonic
from nucleosynthesis predictions?
What is the significance of neutrinos having mass? What are neutrino oscillations?
What are the problems associated with using neutrinos to explain the dark matter?
What are some of the weaknesses of explaining dark matter with baryonic matter?
What are some of the weaknesses of explaining dark matter with non-baryonic matter?
What fraction of the mass of the Universe do we currently think is in baryons? In luminous matter?
In dark matter?
How did the Sun form?
What is the solar nebula?
How did the Jovian planets probably form?
How did the terrestrial planets probably form?
Why are the terrestrial planets smaller than the Jovian planets?
Why do the terrestrial planets not have hydrogen and helium-based atmospheres like the Jovian planets?
Why does the Earth have a heavy metal core?
What is the source of heat in Earth's core?
Why did the growth of the planets from planetesimals stop?
Where is the stuff that remains from the formation
of the planets?
How did the rings of the Jovian planets form?
How did Earth, Mars, and Venus acquire their atmospheres?
Why is the composition of Earth's atmosphere different from that of
Mars and Venus?
What is meant by differential gravity or tidal forces?
Where besides the Earth-Moon system are there examples of
tides in the Solar System?
What is the difference between a lunar and solar eclipse?
What is the cause of the twice-daily tides on Earth?
Why does the Moon always keep the same face to Earth?
What are the requirements for a successful theory of the Moon's formation?
What do we mean by the angular momentum of the Earth-Moon system?
What is the ``fission hypothesis'' of the Moon's formation? What are this theory's successes and failures?
What is the ``double planet hypothesis'' of the Moon's formation? What are this theory's successes and failures?
What is the ``capture hypothesis'' of the Moon's formation? What are this theory's successes and failures?
What is the ``giant impact'' theory of the Moon's formation? What are its successes and problems?
What was the role played by the newer simulations of Robin Canup in developing and complicating
the ``giant impact'' theory?
What are the ``Big Whack II'', ``glancing blow'', and ``shower'' solutions? What are their successes and problems?
How do astronomers estimate the age of the Solar System?
How do astronomers find proto-solar systems elsewhere in the Galaxy?
How do astronomers find extrasolar planets?
What are the basic ideas behind Darwin's theory of evolution?
What was the Miller-Urey experiment and why was it important?
What are the pros and cons of the argument that martian
bacteria may have lived in the meteorite ALH 84001?
What are some of the ways that scientists have suggested we find and communicate with
extraterrestrial life?
What is the ``water hole''?
What is the Drake Equation?
What is astrobiology?
What are extremophiles and why are they important in discussions of extraterrestrial life?
Why is Europa thought to be a possible site for life?
Why do some of arguments suggesting that microbial life might be common in the Universe not
necessarily apply to animal life?
What is the ``Rare Earth Hypothesis''?
What are the reasons that planets like Earth might be very rare in the Universe?
What is the suggested importance of the Moon in the evolution of life on Earth?
What is the suggested importance of Jupiter in the evolution of life on Earth?
What is meant by ``Snowball Earth''?
What is meant by ``inertial interchange event''?
What is the suggested importance of chance events -- Snowball Earth, comet/asteroid impacts, inertial interchange
event -- in the evolution of life on Earth?
What is the suggested importance of plate tectonics in the evolution of life on Earth?
What is the suggested importance of long-lived oceans in the evolution of life on Earth?
What is the suggested importance of liquid water in the evolution of life on Earth?
What is the suggested importance of a star like the Sun in the evolution of life on Earth?
What is the suggested importance of our Sun's location in the Galaxy in the evolution of life on Earth?
What are the likely ``Dead Zones'' in the Universe and why?
What is meant by ``habitable zone'' and ``continuously habitable zone''?
What are the likely differences between animal and microbial habitable zones?
What happens to a habitable zone over time?
What happens to a planet ejected out of a habitable zone?
Why are the habitable zones around stars of different types than the Sun less likely to harbor animal life as we know it?
What is tidal locking?
What is the ``CO2-rock cycle'' and why is it important?
How are the likely inner and outer limits of our Galaxy's habitable zone defined?
Why is it unlikely that the early Universe had habitable zones?
How might microbial life have evolved on Earth?
What are amino acids, DNA, RNA, and proteins?
What are some of the arguments that microbial life might be common in the Universe?
How long did it take for microbial life to develop on Earth compared with the development of
animal life?
What is a eukaryotic cell and what distinguishes it from primitive microbes
like bacteria?
What is endosymbiosis?
How does Lynn Margulis suggest that eukaryotic cells evolved from primitive cells?
What is the significance to complex life of an oxygen-rich atmosphere and how did such an
atmosphere probably develop on Earth?
What is the ``Cambrian Explosion'', what are its suggested causes, and what affect did it have on
the evolution of life on Earth?
How does the Rare Earth Equation differ from the Drake Equation?
What would happen to the estimate of the number of intelligent, communicative civilizations if
one term in the Rare Earth or Drake Equation was close to zero?
Which are the terms in the Rare Earth Equation that we can roughly estimate from
astronomical observations?
Which are the terms in the Rare Earth Equation whose values are so uncertain we can
only speculate about them?
What are the factors that make Earth ideal for intelligent life as we know it?
What are some of the problems with the Rare Earth Hypothesis?
Some Things to Know for the Final Exam: