## homework 10 : Kirkwood gaps

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
Ref: Chicago Manual of Style
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.

## Homework 10: Kirkwood gaps

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
Ref: Chicago Manual of Style
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.

## Can the portrayal of science in media influence how certain…

Can the portrayal of science in media influence how certain research and technology is viewed, and accepted, by the general public (e.g., cloning)?
Do you think the portrayal of scientists in the various forms of media influences how society views people in this profession? Why, or why not?

## Homework 05: gas retention simulator

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.
Sharing of phrasing or formatting with other students is prohibited.
This work is the intellectual property of the instructor and Washington State University. All reproduction or retransmission in whole or in part is strictly prohibited.
NO TITLE PAGE.
Ref: Gas retention simulator (authored by the Columbia Center for New Media Teaching and Learning; Columbia University; hosted on github)
https://ccnmtl.github.io/astro-simulations/gas-retention-simulator/ (Links to an external site.)
Ref: NASA Planetary fact sheet – metric
https://nssdc.gsfc.nasa.gov/planetary/factsheet/index.html (Links to an external site.)
In this exercise we will simulate planetary atmospheres: their composition, temperature, and escape conditions.
In your favorite browser, navigate to the simulation and spend a few minutes playing with the controls. Orient yourself to the display: the box on the upper left is a chamber in which a gas will be contained; the gas particles (atoms or molecules) are represented by little colored balls that move about, and the shade (darker or lighter) of color of each ball indicates how quickly it is moving. The display at upper right shows a histogram of the number of gas particles at a particular speed at any instant.
When you are ready, Reset the simulation (top right).
Pull down the menu entitled Select gases to add and select Xenon. Leave the other settings at their default values. Then select Start simulation. Focus upon a single gas atom and follow it for several seconds. Does it always move at the same speed? If not, what causes its speed to change?
Look at the distribution plot. In the previous question we established that a given particle speeds up and slows down. Why does the distribution plot NOT change over time?
Reset the simulation. Now simulate the atmosphere of Earth as it was 4.5 billion years ago. Add three gases: hydrogen, water, and carbon dioxide. Set the temperature to 288 kelvin (from the NASA fact sheet, Earth’s mean T = 15 C; 15 celcius 273 = 288 kelvin). Check on the box beside Allow escape from chamber. Set the escape speed to 1/8 of Earth’s escape speed, 11.2/8 = 1.4 km/s = 1400 m/s. Start the simulation and wait at least 60 seconds. Which gases escape? Which are retained? Do your results verify what you expected; if so then how, and if not then how not?
Reset the simulation. Now simulate Mars: record here Mars’s mean temperature (kelvin) and 1/8 escape speed (m/s). Add hydrogen, water, and carbon dioxide to the chamber. Start the simulation and wait at least 60 seconds. Does the end result resemble the composition of Mars’s atmosphere today?
Reset the simulation. Now simulate Venus. Record your initial conditions. Record your results. Write a sentence or two of interpretation of your results.
Generalize your results: under what conditions will a gas escape from a planet’s atmosphere? Under what conditions will a gas be retained in a planet’s atmosphere?
Grading: all questions are weighted equally. Total points = [30].

## Homework 01

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 logarithmof 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
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.

## Homework 01: trends and correlations

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 logarithmof 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
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.

How to successfully complete this lab exercise
To successfully complete this lab exercise, just follow these steps:
Complete the pre-lab activity
Perform all activities and answer all questions in the lab report
Check the formatting of the report
Create a PDF file of the Report
Submit the PDF file AND the complete Excel Workbook (do not convert to PDF) with all graphs and tables in the assignment drop boxIntroduction
IntroductionHave you ever wondered how far it is to the Pleiades? It is a local star cluster with hundreds of stars but very well visible to the naked eye. Associated with it is a mythology about seven sisters guarded by their parents. The distance to the Pleiades can be used as a step to calibrate the cosmic distance ladder. In this lab you will learn two different ways to determine the distance to this famous star cluster.

## Photometry of the Pleiades Lab!

How to successfully complete this lab exercise
To successfully complete this lab exercise, just follow these steps:
Complete the pre-lab activity
Perform all activities and answer all questions in the lab report
Check the formatting of the report
Create a PDF file of the Report
Submit the PDF file AND the complete Excel Workbook (do not convert to PDF) with all graphs and tables in the assignment drop boxIntroduction
IntroductionHave you ever wondered how far it is to the Pleiades? It is a local star cluster with hundreds of stars but very well visible to the naked eye. Associated with it is a mythology about seven sisters guarded by their parents. The distance to the Pleiades can be used as a step to calibrate the cosmic distance ladder. In this lab you will learn two different ways to determine the distance to this famous star cluster.

## Solar System Walk

I need that worksheet and excel file back
Step 1: Watch the video
Step 3: Choose a site for your model
Step 4: Determine your model size by measuring the distance you have available to build your model
Step 5: Scale your model by determining the scaling factor