Astro 102 Final Exam Ultimate Study Guide 100% Correct Answers Verified Latest 2024 Version
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Course
ASTRO
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ASTRO
Astro 102 Final Exam Ultimate Study Guide |
100% Correct Answers | Verified | Latest
2024 Version
What are the characteristics of disk stars (yellow) of the Milky Way Galaxy? - High mass stars, the
Sun, youngest stars, and stars that all orbit in nearly the same plane
What are the characterist...
Astro 102 Final Exam Ultimate Study Guide |
100% Correct Answers | Verified | Latest
2024 Version
What are the characteristics of disk stars (yellow) of the Milky Way Galaxy? - ✔✔High mass stars, the
Sun, youngest stars, and stars that all orbit in nearly the same plane
What are the characteristics of halo stars (green) of the Milky Way Galaxy? - ✔✔Globular clusters, oldest
stars, stars whose orbits can be inclined at any angle, and stars with smallest abundance of heavy
elements.
What are the characteristics of spiral galaxies? - ✔✔They contain abundant clouds of cool gas and dust,
are rare in central regions of galaxy clusters, contain bright and hot stars, have significant ongoing star
formation, and have a flattened DISK of stars
What are the characteristics of elliptical galaxies? - ✔✔They are more reddish in color and it contains
primarily old, low mass stars; ALL HALO
Which of the following best describes the status of the Milky Way in our local group of galaxies? - ✔✔it
is one of the two largest galaxies in the group
Our Sun belongs to the... - ✔✔disk component of the Milky way galaxy
The globular cluster M13 belongs to the... - ✔✔spheroidal component of the milky way galaxy.
Which galaxy contains hot, ionized gas but very little cool gas or dust? - ✔✔Elliptical galaxy
The Milky Way is what kind of galaxy? - ✔✔spiral galaxy
What type of galaxy was more common in the universe 10 billion years ago? - ✔✔Irregular galaxy
,What is cosmology? - ✔✔the study of how the distribution of galaxies changes over time
How does the size of a supernova compare with the size of the observable universe? - ✔✔The size of a
supernova is 2/3 the size of the observable universe
Cepheids with longer periods have... - ✔✔higher luminosities
A Cepheid with a period of 30 days has an average luminosity that is.... - ✔✔10, 000 times the luminosity
of the Sun
The greater the luminosity of a Cepheid star, - ✔✔the larger its radius
What are the steps that describe how we use Cepheids as a tool to make cosmic distance
measurements? - ✔✔Step 1: Measure the period of the Cepheid's brightness variations
Step 2: Use the period-luminosity relation to determine the Cepheid's luminosity
Step 3: Calculate the Cepheid's distance from its luminosity and apparent brightness
What baseline distance must we know before we measure a parallax? - ✔✔the Earth-Sun distance
What cosmic distance measurement techniques are considered "standard candle" techniques? -
✔✔Cepheids, white dwarf supernovae (distant standards) and main sequence fitting
* You are using the luminosity of these objects
What would happen if Cepheids did not exist and there were no other standard candle technique that
worked at the same distances? - ✔✔We would not be able to measure the distances of distant galaxies
Why do we use Hubble's law to estimate the distances of most distant galaxies, rather than using white
dwarf supernovae in all cases? - ✔✔We have not observed white dwarf supernovae in most gaalxies
Which technique is the most useful for measuring the distance to a galaxy located 10 million light-years
away? - ✔✔Cepheids
, Rank the diagrams based on how much the galaxy has expanded in size - ✔✔The universe as a whole is
expanding, but gravitational bound objects such as galaxies are not expanding, so the diagrams would
we ranked equally.
How are speed and distance correlated when it comes to galaxies? - ✔✔The further you are, the faster
your speed
* This is Hubble's law
Which evidence supports that the universe is expanding? - ✔✔1. All galaxies in to Coma cluster of
galaxies have redshifted spectra
2. The measured rate of expansion is the same in all directions
3. Galaxies 200 million light-years away move away from us twice as fast as galaxies 100 million light-
years away
Which evidence contradicts that the universe is expanding? - ✔✔1. Spiral galaxies move away from us
10% faster than elliptical galaxies at the same distances
2. Irregular galaxies outside the Local Group are moving toward us
Why is the observation that "irregular galaxies outside the local toward us" contradict that the universe
is expanding? - ✔✔Because Hubble's law predicts that all galaxies outside our Local group should be
moving away from us
Why does the observation "The Andromeda galaxy, a member of our local group, is moving toward us"
NOT contradict the idea that the universe is expanding? - ✔✔Because the galaxies of the local group are
gravitationally bound together. In other words, the universe expands, not its galaxies
We can measure the expansion rate by studying galaxies in many different directions in space and at
different times of year. If we compare such observations, we would find that the expansion rate is -
✔✔the same no matter when or in which direction we measure it.
Which of the following is an important starting assumption of galaxy formation? - ✔✔Some regions in
the universe start out denser than others
Properties of an elliptical galaxy? - ✔✔1. Protogalactic cloud has high density
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