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Astronomy

Ch. 16 Study Questions 1. About how many stars are there in the Milky Way Galaxy

Ch. 16 Study Questions
1. About how many stars are there in the Milky Way Galaxy?
2. Why are Cepheid variable stars useful?
3. What is interstellar extinction?
4. How did Shapley estimate the location of Sun in the Milky Way?
5. Why do astronomer observe 21 cm radio waves to probe the far reaches of the Milky Way?
6. Which components of the Milky Way are the best tracers of spiral arms?
7. What is the diameter of the Milky Way?
8. The presence of what type of object accounts for the very fast orbiting of stars and gas about the center of the Milky Way?
9. Dark matter has been invented to explain a hard-to-understand feature of the Milky Ways rotation. What is that problem feature?
10. Where in the Milky Way do we find the very oldest stars?
Ch. 17 Study Questions
1. What can you say about the size of the nucleus of a spiral galaxy, if the arms are very loosely wound?
2. What is the name of the mechanism believed to produce grand-design spirals?
3. What galaxy type is full of gas and dust? What type is not?
4. What galaxy type is mostly made of old stars?
5. What galaxy type is still undergoing star formation?
6. About how many galaxies are in our own “Local Group?”
7. How do giant ellipticals get so BIG?
8. In a typical cluster of galaxies, what percent of the matter present is luminous (visible)?
9. What is the best evidence that the universe is expanding?
10. In the expanding universe, what is expanding? Atoms? The Solar System? Stars? Galaxies? Something else?

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Astronomy

What angular resolution would you need to see the sun and earth as distinct points of light?

Suppose you were observing our own solar system from your state-of-the-art telescope on the planet you found orbiting Proxima Centauri.
1. What angular resolution would you need to see the Sun and Jupiter as distinct points of light?
2. What angular resolution would you need to see the Sun and Earth as distinct points of light?
3. What diameter would your telescope’s primary mirror need to be in order to obtain these angular resolutions in the optical (400-700nm)?

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Astronomy

How about the other way around, what shows up better in the visible image?

The links here have two images of Jupiter taken in different light wavelength ranges. https://photojournal.jpl.nasa.gov/catalog/pia02873
The first link above is from the Cassini fly-by of Jupiter a few years ago, is a composite image (a combination of various filters using visible wavelengths). The colors were selected to show how Jupiter would appear to the human eye. The second link below is another composite view of Jupiter, this time from the James Webb space telescope, using infrared wavelengths that have been assigned a color based on the wavelength if the infrared filter used.
Webb’s Jupiter Images Showcase Auroras, Hazes – James Webb Space Telescope
Compare the two images and discuss what you see in the bottom infrared image that doesn’t show up well if at all in the top, visible wavelength image. How about the other way around, what shows up better in the visible image? Keep in mind that these were taken at different times. The dark shadow in the top image is a shadow of a moon that happened to be passing when the image was collected, so you won’t see that on the bottom image.
Write a good solid paragraph for full credit. Remember that infrared is invisible to the human eye, and also that even images take in the wavelengths of light we see use filters of specific colors that are combined to make the image.

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Astronomy

Do you agree withthe ethics of those decisions?

What is a heat shield and why is it necessary for any space vehicle to return to Earth?
What animals were launched into space and by what countries? Do you agree withthe ethics of those decisions? (There’s no right answer to this part!)
What is a launch escape system and how does it function?
Describe the significance of the following missions:(a) Mercury-Redstone 3 (b) Gemini 4(c) Gemini 6/7 (d) Gemini 8(e) Apollo 8 (f) Apollo 11
Describe what happened to Apollo 1 and how it occurred.
Identify the function of the following components of the Apollo spacecraft:(a) The lunar module (LM)
(b) The command service module (CSM)(c) The command module (CM)
What happened to Apollo 13 and how did it return to Earth?

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Astronomy

If the cat discovers a sundial without a cat on it, the cat will remedy the problem.

Use instructions in the following link to build a simple sundial:
https://www.wikihow.com/Make-a-Sundial
Three methods are discussed. I want you to use method 2: Paper plate sundial. I know in method 2 the sundial looks like a clock. That is MISLEADING. The sundial will NOT come out looking like a clock. If you draw a clock on the paper plate, you get 0/10.
Wherever the instructions refer to “celestial pole,” they mean NORTH. Use a compass or the fake compass on your phone to find the direction to north.
You do not have to make a twelve-hour sundial. Noon to six is good enough. Or 9 a.m. to 3 p.m. Some six-hour interval.
It is very important that you DO NOT MOVE the sundial at any time during construction or after you have finished it. It will not tell correct time if you move it. Push nails or tacks through it to hold it to the ground. Or at least put a rock on it. If your sundial moves overnight, it will not work the next day. Be very careful if you own a cat. If the cat discovers a sundial without a cat on it, the cat will remedy the problem.
After the sundial is built, I want you to take two photos of the shadow showing times on the sundial, on the hour. In other words, take a photo of the sundial when it reads 1pm, and 3pm. Or any two other times that you want. For ten points, send me the photos. Be sure the sundial does not move overnight. If I see any evidence that the sundial has changed in any way between the first photo and the second, NO POINTS. The ultimate mistake is making two sundials, one for each photo. One of your predecessors did that.
The mistake that has cost your predecessors the MOST POINTS is this: writing in numbers on the paper plate to make it look like a clock, then taking pictures as the shadow moves. NO. WRONG. I can easily tell if you did that. You must use the shadow to determine where the numbers go. The numbers will not be evenly spaced like on a clock.
If you are not having any luck, check to see that the Sun is up and the sky is clear, and that there are no shadows from buildings or trees, falling on your sundial.
If you don’t get it, contact me. I can easily straighten you out.

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Astronomy

3- how do we know what we find belong to mars?how do you identify something?

Sources to be cited
2
Paper format
MLA
1-Define life and what is required for life.
2- Focus on missions and discoveries toward the required elements for
life (like water, radiation, air, oxygen, methane, etc…)
3- How do we know what we find belong to Mars?How do you identify something?
4- Make conclusion only based on your own facts and discoveries stated
in previous sections.
5- Use the Template and follow the IEEE or AIP citation style.
6- You need peer reviewed article and most recent publications. the
older the publication the higher is the chance they are not complete
or correct any more.
400-800 words maximum

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Astronomy

Why are stars different colors?

Ch. 12 Study Questions
1. What is the measured parallax of stars used for?
2. Which is brighter, magnitude 5 or magnitude 0?
3. What two things does a star’s apparent magnitude depend on?
4. What one thing does a star’s absolute magnitude depend on?
5. What is a star’s luminosity?
6. Why are stars different colors?
7. What physical property of a star is reflected by spectral type?
8. What physical property of a star is reflected by luminosity class?
9. What two quantities are plotted on the axes of the HR diagram?
10. What do astronomers observe in order to tell if a star is Main Sequence, or one of the evolved giants?

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Astronomy

What are the three layers of the suns atmosphere, from bottom to top?

Ch. 11 Study Questions
1. What two chemical elements is the Sun chiefly made of?
2. How hot (in Kelvin) is the surface of the Sun?
3. How hot (in Kelvin) is the center of the Sun?
4. What are the three layers of the Suns atmosphere, from bottom to top?
5. The Sun is made of plasma. What is plasma?
6. What are granules, seen on the surface of the Sun?
7. Why are sunspots darker than the surrounding solar surface?
8. What is the most powerful eruption on the Sun?
9. What is the nuclear reaction that powers the Sun?
10. How long has the Sun been “burning?”
11. If the Sun really were “on fire,” how long would it shine?

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Astronomy

Identify (at least) six kirkwood gaps: list the distances from the sun at which zero asteroids are found.

General instructions for assignments
All responses must be typed.
All calculations must be shown in full.
All graphs must be electronically produced.
All references must be cited using Chicago Manual of Style conventions.
NO TITLE PAGE Ref: NASA/JPL Solar system dynamics pages: Asteroid Main Belt Distribution
https://ssd.jpl.nasa.gov/?histo_a_astLinks to an external site.
Ref: Chicago Manual of Style
https://www.chicagomanualofstyle.org/home.htmlLinks to an external site.
The URL above links to a histogram of number of asteroids versus their average distance from the Sun (“semi-major axis” is the average distance). Clearly, there are populated distances and unpopulated distances. The unpopulated distances are called Kirkwood gaps.
Your task is to (1) identify six Kirkwood gaps in this histogram, (2) calculate how long a hypothetical object inside the gap would take to orbit the Sun once, and (3) check that this object’s orbit time is in resonance with Jupiter. (4) Lastly, write a Chicago-style reference for this web page.
Identify (at least) six Kirkwood gaps: list the distances from the Sun at which zero asteroids are found. This list must include the four labeled gaps and at least two unlabeled gaps.
Calculate orbit times: you can use a simple rule for calculating orbit times from orbit distances,
(orbit time in years)=(orbit distance in AU)3/2
Check for resonance: divide Jupiter’s orbit time by the asteroid’s orbit time (both in years); express your result to at least 3 significant figures. If in resonance then your decimal result can be converted to a simple ratio. A simple ratio is a fraction of small integers. This task is not simple: your simple ratio should agree with your decimal result to at least 2 sig figs, and ideally three.
Finally, for this web page write down the full citation using Chicago Style.
Here is an example calculation and response you are allowed to imitate:
The first gap is at a distance of 2.5 AU. Using the formula, I calculate an orbit time = 2.53/2 = 3.95 years, in other words, a hypothetical asteroid at a distance of 2.5 AU from the Sun would orbit the Sun once every 3.95 years. To check for resonance, I divide into Jupiter’s orbit time of 11.86 years; 11.86 years / 3.95 years = 3.00 (years divided by years produces a unitless quantity). Or, I could write 11.86:3.95 = 3.00:1.00. The simple ratio is therefore 3:1. In other words, for every three asteroid orbits, Jupiter orbits exactly once. I have thus verified the 3:1 orbit resonance.
Grading: (1) [6 points] Identify at least 6 Kirkwood gaps, 4 of which are labeled on the diagram and at least two of which are not.
(2) [12 points] Calculate the orbital period of a hypothetic asteroid in each of the 6 gaps.
(3) [6 points] Reduce the Jupiter-to-asteroid ratio to a simple ratio.
(4) [6 points] Write a full Chicago style citation, including the author’s name.

Categories
Astronomy

Ref: NASA Space Science Data Center (NSSDC)

Ref: NASA Space Science Data Center (NSSDC)
http://nssdc.gsfc.nasa.gov/planetary/factsheet/index.html (Links to an external site.)
The NSSDC is a standard database for planetary sciences. One method of investigation common in the sciences is to plot lots and lots of data and look for trends. For the 10 solar system objects listed on the given URL, plot two graphs, then answer the questions.
To plot linear or logarithmic data, you have the choice of (1) changing the scale of the axes, or (2) plotting the logarithm
of the data values; your choice (be sure to label your axes properly).
Make a scatter plot of mean temperature (y) versus distance from the Sun (x). Use a LINEAR scale. NOTE: for the Moon, do NOT use the Moon-to-Earth distance, use the Moon-to-Sun distance (same as Earth-to-Sun distance). Look at the plot. Answer the questions:
Describe the trend: rising, falling, or no trend.
Do the points fall along a straight line?
Is it easy to identify which point is which planet using only your eyes? Why not?
Is it easy to identify outliers using only your eyes? Why not?
For the same data, mean temperature (y) versus distance from the Sun (x), make a scatter plot with a LOGARITHMIC scale for the x-axis only. Look at the plot. Answer the questions:Describe the trend: rising, falling, or no trend.
On which plot, linear or logarithmic, do the points appear to be on a “straighter” line?
On which plot, linear or logarithmic, is it easier to identify each planet? Why?
On which plot, linear or logarithmic, is it easier to identify the outliers? Why?
Plotting data on logarithmic axes is one way of “linearizing” a data set. Describe three advantages of the logarithmic axis plot versus the linear axis plot.
Discuss cause and effect: why is the trend a falling one? You can rely upon your intuition for this response.
Discuss cause and effect: which is the outlier, and what causes the anomalously high temperature? For this answer you will have to do some research; write a full citation to your source using Chicago style.
Grading: [10] points for the two scatter plots, [18] points for responses to the questions (correct and complete), [2] points for the Chicago style citation. Total points = [30]. Passing grade = [18].
APPENDIX
Plots are easily made using a spreadsheet.
Log in to your Office365 account. You access this from your student account, or go directly to office365.wsu.edu.
Open OneDrive. From the pull-down menu +New select Excel workbook.
Enter the values in columns. Use column A for x values and column B for y values.
Use click-and-drag to highlight the numbers in the columns.
Select the Insert menu. Select “scatter with only markers”.
A plot will appear. You can manipulate the plot by clicking on its various parts. Click the title to change the title. Click on each axis to change the axis to logarithmic, or to add an axis label.